2.1 State Contingency Plan
...responses and responses to contaminated surface water, drinking water, outdoor air, soil vapor, or leaking underground tanks, the HEER Office may refer cases to or work closely with other ...
 

2.4 Environmental Cleanups
...environmental hazards (e.g., free product discharging into a surface water body or vapor intrusion into a building) and prepare an Environmental Hazard Management Plan to address ...
 

3.0 Site Investigation Design And Implementation
...levels of tetrachloroethylene in groundwater during a site investigation could suggest vapor intrusion as a potential environmental hazard (e.g., groundwater action level for vapor intrusion ...
 
...intrusion as a potential environmental hazard (e.g., groundwater action level for vapor intrusion exceeded). This could trigger the collection of soil gas samples in the source area ...
 
...could then lead to the need to seal floors in order to prevent the potential intrusion of vapors into the building. Linking the Site Investigation and Environmental Hazard Evaluation ...
 

3.2 Systematic Planning Of Site Investigation
...and nature of potential environmental hazards at a site (e.g., direct exposure, vapor intrusion, leaching to groundwater, etc.). The site investigation must be designed to meet ...
 
...2014), may not be adequate. The presence of other potential hazards such as leaching, vapor intrusion, gross contamination and ecotoxicity concerns must also be evaluated using ...
 
...a potential environmental hazard posed by volatile chemicals is the intrusion of vapors into existing or future buildings. The need to collect soil gas data should be evaluated ...
 
...gas data at sites where initial soil and/or groundwater data indicate potential vapor intrusion hazards. Analysis of soil samples that exceed ...
 
...pose a threat to groundwater resources or is highly volatile and could pose potential vapor intrusion hazards for buildings (e.g., water-soluble pesticides, solvents, light-end petroleum ...
 
...the optimal area and depth of the DUs to evaluate potential exposure, leaching, vapor intrusion and/or gross contamination concerns? What is the optimal area ...
 
... How many soil gas samples are required to adequately assess potential vapor intrusion hazards? Is the collection of sorbent tube samples for TO-17 ...
 
...Do reported concentrations of COPCs in soil or groundwater data present potential vapor intrusion concerns, indicating the need for soil gas or indoor air sampling data (Section ...
 

3.3 Conceptual Site Models
...exposure to impacted soil (ingestion, dermal absorption, inhalation of vapors and dust in outdoor air); Emission of subsurface vapors to ...
 
...and dust in outdoor air); Emission of subsurface vapors to building interiors; Leaching and contamination of groundwater ...
 
... ecotoxicity); Gross contamination conditions (explosive subsurface vapor conditions, odors, general resource degradation, etc.); Contaminated ...
 
...water resources (toxicity, taste and odors); Emission of subsurface vapors to building interiors; Discharges of contaminated groundwater ...
 
... Gross contamination conditions (generation of explosive vapors from free product, odors, sheens, general resource degradation, etc.). ...
 
... site conditions but could pose a threat under future conditions (e.g., potential vapor intrusion hazards identified but no buildings currently on site; refer to Section 13 and ...
 
... purposes, with contaminated soil covered by existing buildings and pavements and no vapor intrusion concerns). Contaminant concentrations at the site could, however, indicate a ...
 
... (along with other relevant information): Additional soil, soil vapor or groundwater data; Location of existing monitoring wells ...
 

3.4 Selection Of Decision Units
...generally necessary to evaluate environmental hazards associated with soil leaching, vapor intrusion and gross contamination hazards (see Step 8 in Subsection 3.2 and ...
 
... 2011b). If the target contaminant at the site poses leaching, vapor intrusion and gross contamination hazards, then the spill area should be designated as ...
 
...including leaching of contamination to subsurface groundwater resources, intrusion of vapors into overlying buildings and nuisance or even explosion hazards associated with grossly ...
 

3.6 Sampling And Analysis Plans
...method procedural guidance for soil and sediment, groundwater and surface water, and soil vapor and indoor air is presented in Sections 5, 6, and 7, respectively. The application ...
 

3.9 Site Investigation Reports
...that additional data be collected at the site (e.g., soil gas data to evaluate potential vapor intrusion concerns) or that additional tests be carried out on existing samples. After all ...
 

3.10 Environmental Hazard Evaluation
...report. In the absence of obvious conditions in the field (e.g., explosive levels of soil vapors), the most expeditious approach to identifying potential environmental hazards associated ...
 
...that batch testing and/or groundwater data may be needed. The identification of potential vapor intrusion concerns suggests that soil gas data are needed. Applying this type of ...
 

4.2 Use Of Multi Increment Samples To Characterize DUs
...by the concurrent or followup collection of groundwater (Section 6) and/or soil vapor samples (see Section 7). Volatile chemicals primarily pose potential leaching and/or ...
 
... Section 7). Volatile chemicals primarily pose potential leaching and/or vapor intrusion hazards. These concerns can be more directly addressed through testing of groundwater ...
 
...These concerns can be more directly addressed through testing of groundwater and soil vapors. 4.2.4 INCREMENT DISTRIBUTION ...
 
...For the purposes of this Section, a chemical is considered to be semi-volatile if its vapor pressure is between 0.1 and 1.0 mm Hg or if it is a liquid at 25ºC or if the Henry’s Law ...
 
...collection are acceptable for air drying (if needed) even when determining higher vapor pressure SVOCs. This and other alternative approaches should be discussed with the HEER ...
 
...is considered to be volatile if the molecular weight is less than 200 and the vapor pressure is greater than 1 mm Hg (25ºC) or the Henry’s Law Constant is greater than 0.00001 ...
 
... chemicals. Primary environmental hazards posed by VOC-contaminated soil include vapor intrusion, leaching and gross contamination hazards. This normally requires that spill ...
 
...Soil gas data are much more reliable than soil data for evaluating potential vapor intrusion hazards associated with volatile contaminants in soil (and groundwater). Soil ...
 

5.6 Collection Of Multi Increment Samples For VOC Analysis
... increments for MI samples are collected in separate sampling devices that have vapor tight seals and are designed for zero headspace (e.g. Core N� One™, EnCore™, ...
 
...sample collection (see Section 11.2). Note that to freeze samples in small cores with vapor-tight seals to temperatures between -7°C and -15°C (for temporary storage and shipping) ...
 

5.8 Field Documentation
...could be indicative of solvent compounds. Use of a field organic vapor analyzer for screening purposes is recommended when volatile or semi-volatile organic contaminants ...
 

6.0 Groundwater and Surface Water Sampling Guidance
...as part of a larger investigation that also involves subsurface soil sampling and/or soil vapor sampling. In either case, the initial site preparation and boring/drilling methods described ...
 

6.5 Groundwater Sample Collection Methods
... previous sampling events. If the order is not known from previous sampling events, use vapor readings collected at the top of the well casing to aid in determining the correct order. This ...
 

7.0 Soil Vapor and Indoor Air Sampling Guidance
... ' SECTION 7 SOIL VAPOR AND INDOOR AIR SAMPLING GUIDANCE Interim Final - December 2017 ...
 

Contents
... 7.1 Occurrence of Subsurface Vapor Plumes   ...
 
...   7.2 Soil Vapor Transport Mechanisms and Conceptual Site Models ...
 
...   7.2.1 Factors Affecting Subsurface Vapor Flow and Impacts to Indoor Air   ...
 
... 7.2.2 Preparation of Conceptual Site Models for Soil Vapor Investigations   ...
 
... 7.3 Development of Vapor Intrusion Screening Tools   ...
 
...   7.4 Soil Vapor Investigations   ...
 
... 7.5 Collection of Representative Soil Vapor Samples   ...
 
...   7.6 Soil Vapor Sampling Strategies   ...
 
... 7.6.1 Determining When to Collect Soil Vapor Samples   7.6.2 ...
 
...   7.6.2 Soil Vapor Sampling Design     ...
 
...   7.6.2.2 Soil Vapor Sampling Point Locations   ...
 
...   7.6.2.3 Soil Vapor Sample Depths and Depth Intervals   ...
 
...   7.6.2.4 Soil Vapor Sample Screen Intervals   ...
 
...   7.8.3.1 Passive Soil Vapor Sample Collectors     ...
 
...   7.9 Active Soil Vapor Probe Installation   ...
 
...   7.9.4 Soil Vapor Probe Tubing   7.9.5 ...
 
...   7.9.5 Soil Vapor Probe Abandonment   ...
 
...   7.10 Active Soil Vapor Sampling Procedures   ...
 
...   7.10.1 Soil Vapor Sample Timing and Frequency   ...
 
...   7.10.2 Soil Vapor Probe Equilibration   ...
 
...   7.10.3 Soil Vapor Probe Purging     ...
 
...   7.10.4 Soil Vapor Sampling Trains   7.10.5 ...
 
...   7.10.5 Soil Vapor Probe Leak Testing   ...
 
...   7.10.5.2 Water Dam Vapor Point Test     ...
 
...   7.10.6 soil vapor sample collection steps   ...
 
...   7.10.7 Soil Vapor Sample Notes and Logs   ...
 
...  7.12 Passive Soil Vapor and Indoor Air Sample Collection Procedures ...
 
...   7.12.1 Passive Sampling of Soil Vapor   7.12.2 ...
 
...   7.13 Soil Vapor And Indoor Air Sample Analysis   ...
 
...   7.14.1 Soil Vapor Sample Evaluation   7.14.2 ...
 
... 7.15 Documentation of Soil Vapor or Indoor Air Sampling   ...
 
...   7-1. Example Vapor Plume Contours and Vapor Intrusion Pathways.   ...
 
...Plume Contours and Vapor Intrusion Pathways.   ...
 
...   7-2 Conceptual Model of Soil Vapor Transport Including Biodegradation Process.   ...
 
... 7-3 Complete Exposure Pathway CSM for Soil Vapor to Indoor Air.   7-4 ...
 
...   7-4 Schematic of Soil Vapor Concentration Profile.   ...
 
...   7-10 Two Examples of Passive Soil Vapor Sample Collectors.   ...
 
...   7-13 Summary of high-density, passive sampler data for PCE vapors beneath the slab of a former dry cleaner.   ...
 
...   7-14 Designation of soil vapor DU beneath a building slab for collection of LVP samples. ...
 
... Example options for designation of purge points for collection of LVP subslab vapor samples.;   7-16 Floor drain and suspect ...
 
...system.   7-19 Installation of LVP vapor extraction point used in HDOH (2017) field study. ...
 
...   7-22 Typical Temporary Soil Vapor Probe   7-23 ...
 
...   7-23 Installing a Temporary Soil Vapor Probe Using a Direct-Push Drill Rig   ...
 
...   7-24 Vapor Point Completions   7-25 ...
 
...   7-25 Typical Nested Permanent Soil Vapor Sampling Probes   7-26 ...
 
...   7-26 Installation of a Permanent Soil Vapor Probe   7-27 ...
 
...   7-27 Schematic of Typical Sub-Slab Soil Vapor Sampling Probe (see also Figure 7-28 & 7-29). ...
 
...   7-28 Sub-Slab Soil Vapor Sampling Probes   7-29 ...
 
...   7-29 Sub-Slab Soil Vapor Sampling Probes   7-30 ...
 
...   7-30 Installation of a Vapor Pin™ with a silicon sleeve directly into slab ...
 
...   7-31 Soil Vapor Probe Purging Devices   ...
 
...is drawn on sealed lung box, causing the Tedlar bag to pull vapor from the collection point and fill.   ...
 
...   7-35 Example Soil Vapor Sample Collection Setups   ...
 
...   7-36 Soil Vapor Sampling Trains Arranged for Shut-in Test (see also Figure 7-35) ...
 
...Sealed to Floor with Inert Putty for Leak Testing Slab-mounted Vapor Point   7-38 ...
 
...   7-38 Shroud Over Vapor Probe Surface Completion   ...
 
...   7-41 Installing a Passive Soil Vapor Sample Collector by Hand.   ...
 
...  7-42 Example Plume Map from Grid-based Passive Soil Vapor Survey.   7-43 ...
 
...   7-1 Decision Logic for Subsurface Vapor Hazards   7-2 ...
 
...   7-3 Comparison of Soil Vapor & Indoor Air Sampling Approaches   ...
 
...   7-4 Common Soil Vapor Concentration Unit Conversion Factors   ...
 
...   7-10 Summary of Soil Vapor & Indoor Air Analytical Methods1   ...
 
... 7-11 HDOH-Recommended Laboratory Analytical Methods for Soil Vapor or Indoor Air Contaminants and Leak Detection Compounds ...
 

7.0 Soil Vapor and Indoor Air Sampling Guidance
... ' 7.0 SOIL VAPOR AND INDOOR AIR SAMPLING GUIDANCE This section of the Technical Guidance Manuall ...
 
...section of the Technical Guidance Manuall addresses the collection of subsurface soil vapor samples and indoor air samples. The guidance was developed following review of numerous guidance ...
 
...of sample collection is preceded by an overview of the occurrence and nature of vapor plumes in the subsurface and the potential risks posed to outdoor air and overlying buildings. ...
 
... air and overlying buildings. The development of HDOH soil, groundwater and soil gas (�vapors�) action levels for evaluation of vapor intrusion hazards is described in the document Evaluation ...
 
...action levels for evaluation of vapor intrusion hazards is described in the document Evaluation of Environmental Hazards at Sites ...
 

Figures
...   7-1. Example Vapor Plume Contours and Vapor Intrusion Pathways.   ...
 
...Plume Contours and Vapor Intrusion Pathways.   ...
 
... 7-2 Conceptual Model of Soil Vapor Transport Including Biodegradation Process. ...
 
... 7-3 Complete Exposure Pathway CSM for Soil Vapor to Indoor Air.   7-4 ...
 
... 7-4 Schematic of Soil Vapor Concentration Profile.   ...
 
... 7-10 Two Examples of Passive Soil Vapor Sample Collectors.   ...
 
... 7-22 Typical Temporary Soil Vapor Probe.   7-23 ...
 
... 7-23 Installing a Temporary Soil Vapor Probe Using a Direct-Push Drill Rig. ...
 
...   7-24 Vapor Point Completions.   ...
 
... 7-25 Typical Nested Permanent Soil Vapor Sampling Probes.   7-26 ...
 
... 7-26 Installation of a Permanent Soil Vapor Probe.   7-27 ...
 
... 7-27 Schematic of Typical Sub-Slab Soil Vapor Sampling Probe (see also Figure 7-28 & 7-29). ...
 
...   7-28 Sub-Slab Soil Vapor Sampling Probes.   7-29 ...
 
...   7-29 Sub-Slab Soil Vapor Sampling Probes.   7-30 ...
 
... 7-30 Installation of a Vapor Pin™ with a silicon sleeve directly into slab. ...
 
...   7-31 Soil Vapor Probe Purging Devices.   ...
 
...bag. Vacuum is drawn on sealed lung box, causing the Tedlar bag to pull vapor from the collection point and fill.   ...
 
...   7-35. Example Soil Vapor Sample Collection Setups.   ...
 
...   7-36 Soil Vapor Sampling Trains Arranged for Shut-in Test (see also Figure 7-35). ...
 
..."Water Dam" Sealed to Floor with Inert Putty for Leak Testing Slab-mounted Vapor Point.   7-38 ...
 
...   7-38 Shroud Over Vapor Probe Surface Completion.   ...
 
... 7-41 Installing a Passive Soil Vapor Sample Collector by Hand.   ...
 
... 7-42 Example Plume Map from Grid-based Passive Soil Vapor Survey.   7-43 ...
 

Tables
... 7-1 Decision Logic for Subsurface Vapor Hazards   7-2 ...
 
... 7-3 Comparison of Soil Vapor & Indoor Air Sampling Approaches.   ...
 
...   7-4 Common Soil Vapor Concentration Unit Conversion Factors.   ...
 
... 7-10 Summary of Soil Vapor & Indoor Air Analytical Methods.   ...
 
... HDOH-Recommended Laboratory Analytical Methods for Soil Vapor or Indoor Air Contaminants and Leak Detection Compounds. ...
 

7.1 Soil Vapor Transport Mechanisms and Conceptual Models
... ' 7.1 OCCURRENCE OF SUBSURFACE VAPOR PLUMES Sites where releases of volatile organic compounds (VOCs) can be of concern ...
 
...of volatile chemicals from contaminated soil and groundwater can create a plume of vapors in the vadose zone. These plumes can adversely impact indoor air if drawn into an overlying ...
 
...impact indoor air if drawn into an overlying building, a key topic of this section. Vapors emitted at the ground surface can also affect outdoor air. This issue is addressed separately ...
 
...soil, however, and is considered to pose less of a threat to human health than vapor intrusion into buildings (see HDOH, 2016). Vapors in vadose-zone soil could also migrate downwards ...
 
...intrusion into buildings (see HDOH, 2016). Vapors in vadose-zone soil could also migrate downwards and impact groundwater that has otherwise ...
 
...at MTBE release sites on the mainland. The majority of subsurface vapor plumes in Hawai�i are associated with subsurface released petroleum fuels including gasoline, ...
 
...petroleum fuels including gasoline, diesel and jet fuel. As discussed in Section 7.13, vapors emitted from petroleum fuels are evaluated in terms of Total Petroleum Hydrocarbons (TPH) ...
 
...can also be of importance at some sites. As discussed in Section 7.6, petroleum-related vapor plumes that could pose hazards for overlying buildings are almost always associated with ...
 
... of petroleum compounds by naturally occurring bacteria in the soil will ensure that vapor plumes rarely migrate more than 15 to 30 feet vertically through unconsolidated soil and more ...
 
...the source area (see Section 7.6.1). A smaller number of subsurface vapor plumes in Hawai�i are associated with releases of chlorinated solvents from dry cleaners (e.g., ...
 
...tetrachloroethene or �PCE�) or parts washing operations (e.g., trichloroethene or �TCE�). Vapors emitted from these releases are evaluated in terms of the primary product released as well ...
 
...and in particular the greater persistence of chlorinated solvents can lead to potential vapor intrusion concerns even in the absence of free product in soil or groundwater. Dilute plumes ...
 
...period of operation. The presence of high levels of vinyl chloride in groundwater or soil vapor at sites often indicates the presence of co-located petroleum contamination. The vinyl chloride ...
 
... in the presence of petroleum. The presence of significant breakdown products in soil vapor or groundwater signifies the need to look for petroleum contamination in the same area. ...
 
... in the same area. Due to the inherent heterogeneity of VOCs in subsurface vapor plumes and the uncertainty of upward vapor migration from deeper areas, HDOH emphasizes the ...
 
...plumes and the uncertainty of upward vapor migration from deeper areas, HDOH emphasizes the collection of soil vapor samples from immediately ...
 
...migration from deeper areas, HDOH emphasizes the collection of soil vapor samples from immediately beneath a building slab for evaluation of potential vapor intrusion ...
 
...samples from immediately beneath a building slab for evaluation of potential vapor intrusion hazards (see Section 7.6.2.3). The concurrent collection and evaluation of deeper ...
 
...hazards (see Section 7.6.2.3). The concurrent collection and evaluation of deeper soil vapor samples is also typically recommended for heavily-contaminated properties. Data from deeper ...
 

7.2 Soil Vapor Intrusion to Indoor Air
... ' 7.2 SOIL VAPOR TRANSPORT MECHANISMS AND CONCEPTUAL SITE MODELS 7.2.1 Factors Affecting Subsurface ...
 
...AND CONCEPTUAL SITE MODELS 7.2.1 Factors Affecting Subsurface Vapor Flow and Impacts to Indoor Air As introduced in the previous section, understanding ...
 
...to Indoor Air As introduced in the previous section, understanding how vapors are generated, migrate in the subsurface and can intrude an overlying building is important ...
 
... (e.g., see USEPA 2004e). In practice, estimation of the upward, mass flux of vapor-phase VOCs in the subsurface and prediction of VOC concentrations in subslab soil vapor is ...
 
...VOCs in the subsurface and prediction of VOC concentrations in subslab soil vapor is very difficult. Figure 7-1: Example Vapor ...
 
...is very difficult. Figure 7-1: Example Vapor Plume Contours and Vapor Intrusion Pathways. Vapor-phase chemicals diffuse away from a ...
 
...Plume Contours and Vapor Intrusion Pathways. Vapor-phase chemicals diffuse away from a source area. Wind effects ...
 
...Intrusion Pathways. Vapor-phase chemicals diffuse away from a source area. Wind effects (or heating) can cause depressurization ...
 
...(or heating) can cause depressurization of buildings and advective intrusion of vapors. Air conditioning (AC) can over pressurize a building as fresh air is brought inside and ...
 
...of air into the subslab space. Source: Modified from API 2005. Upward migration of vapors dominated by diffusion; advective flow limited to near vicinity (a few feet or less) ...
 
...buildings. Concentrations of VOCs in shallow or subslab soil vapor are oftentimes significantly lower than would be predicted by models based on the soil type ...
 
...the field (see HDOH, 2016, USEPA, 2012). This is due in part to dissolution of vapors into soil moisture but can also include adsorption to or diffusion into clays in the ...
 
...include adsorption to or diffusion into clays in the soil and permanent removal from the vapor plume, a mechanism not directly taken into account in the vapor intrusion models. The heterogeneous ...
 
...plume, a mechanism not directly taken into account in the vapor intrusion models. The heterogeneous nature of contaminant distribution in soil, both sorbed ...
 
...nature of contaminant distribution in soil, both sorbed to soil particles and in vapor phase, complicates the collection of representative data. These factors highlight the need ...
 
... the collection of representative data. These factors highlight the need to collect soil vapor data in the immediate vicinity of potentially affected buildings as a routine part of vapor ...
 
...data in the immediate vicinity of potentially affected buildings as a routine part of vapor intrusion studies when general site knowledge suggest a potentially significant vapor intrusion ...
 
...intrusion studies when general site knowledge suggest a potentially significant vapor intrusion risk. Limitations on the utility of traditional, small-volume sample data due random, ...
 
...small-scale heterogeneity can also be overcome by the collection of �Large Volume Purge� vapor samples beneath building slabs (Section 7.8.5). Vapors migrate in ...
 
...samples beneath building slabs (Section 7.8.5). Vapors migrate in subsurface soils primarily by diffusion from high- to low-concentration areas (Figure ...
 
...soils primarily by diffusion from high- to low-concentration areas (Figure 7-1). Vapors diffuse much more rapidly through air-filled pore space than water-filled pore space. Advective ...
 
... through air-filled pore space than water-filled pore space. Advective flow of vapors caused by pressure differentials (e.g., flow from high- to low-pressure areas) can occur in ...
 
...USEPA 2012d). Wind-induced depressurization of buildings will be the most likely cause of vapor intrusion in Hawai�i. Wind can create a low-pressure zone on the downwind side of a building. ...
 
...Air pulled out of the building as a result can lead to the advective flow of subsurface vapors through cracks and gaps in the floor. This is taken into account in building and HVAC system ...
 
...of indoor air into subslab soils (see also USEPA 2012d). Samples of subslab soil vapor would in turn reflect the concentration of VOCs in indoor air samples, rather than a subsurface ...
 
...than a subsurface source. This presumably explains the apparent absence of significant vapors immediately beneath slabs of air-conditioned buildings that overlie shallow, petroleum free ...
 
... contaminated soil. In this case, the sudden, upward �attenuation� of deeper soil vapors in the immediate vicinity of a building slab is not attributable to biodegradation. ...
 
...slab is not attributable to biodegradation. Note that an upward diffusion of vapors into the subslab area could also occur when the air conditioning is turned off in the night ...
 
...has not been studied in detail. In theory, this could lead to the intrusion of subsurface vapors into the building during these time periods. In practice, this is likely to be offset by the ...
 
...time periods. In practice, this is likely to be offset by the time required for deeper vapors contaminants to diffuse into the zone of advective transport. Impacts to indoor air by intruding ...
 
...to diffuse into the zone of advective transport. Impacts to indoor air by intruding vapors are also likely to be offset by increased impacts from indoor sources (see Section ...
 
...on a site-specific basis, however, at sites considered to be of high risk for potential vapor intrusion. Concentrations of volatile chemicals in indoor air associated with indoor ...
 
...with operation of the building HVAC system are important to recognize as part of a vapor intrusion investigation and to consider when determining the timing and frequency of sample ...
 
... Section 7.11, if indoor air samples are desired or required to further assess potential vapor intrusion hazards then they should be collected under normal building ventilation and operation ...
 
... Figure 7-2: Conceptual Model of Soil Vapor Transport Including Biodegradation Process. Source: Adapted from API 2005. Note hypothetical ...
 
...hypothetical anaerobic zone immediately beneath the building due to biodegradation of vapor-phase petroleum compounds and inadequate replenishment of oxygen. ...
 
...reached groundwater. As the water table falls and exposes this smear zone, an increase in vapor emissions can occur. As the water table rises some product may rise with it and continue to ...
 
...can occur. As the water table rises some product may rise with it and continue to pose vapor emission hazards. A substantial portion is likely to remain trapped in the smear zone below ...
 
...smear zone below the water table, however. This can result in a substantial reduction in vapor emissions during the wet season. The collection of deep and/or subslab soil vapor samples during ...
 
...emissions during the wet season. The collection of deep and/or subslab soil vapor samples during both the wet and dry season is, recommended for sites where exposure of a significant ...
 
...and fall of the water table with fluctuating tides could also influence the migration of vapors in the vadose zone. Indoor air could be pulled out of the building and into the subslab zone ...
 
...Hawai�i, typically less than one-foot, are unlikely to cause significant fluctuations in vapor concentrations due to exposure and flooding of smear zones. Tidal pumping of air into and out ...
 
...a well-oxygenated zone under a building slab and help protect against significant vapor intrusion associated with subsurface, petroleum contamination. As discussed in ...
 
...pumping is not necessary for general screening purposes. The collection of subslab soil vapor samples during periods of both falling and rising water table may be recommended or required, ...
 
... contamination. 7.2.2 Preparation of Conceptual Site Models for Soil Vapor Investigations Consideration of subsurface vapors and the potential for soil vapor ...
 
...Investigations Consideration of subsurface vapors and the potential for soil vapor intrusion should be included in an overall conceptual site ...
 
...and the potential for soil vapor intrusion should be included in an overall conceptual site model (CSM) and used to design sampling ...
 
...reflect the representative, average subsurface conditions and building susceptibility to vapor intrusion over time and during normal building operation. This is important, because the soil ...
 
... TPH) to thirty-year time period (cancer risk; e.g., benzene and PCE). A focus on soil vapor samples collected during periods of high water table or vapor flux assumptions during periods ...
 
...samples collected during periods of high water table or vapor flux assumptions during periods when a building is over-pressurized can lead to the underestimation ...
 
...periods when a building is over-pressurized can lead to the underestimation of potential vapor intrusion hazards. A focus on subsurface data collected during periods of low water table or ...
 
...low water table or periods when the building is under-pressured and most susceptible to vapor intrusion could overestimate the actual risk and lead to unnecessary remedial actions. An understanding ...
 
...of the CSM is therefore very important. A simple conceptual model of soil vapor transport includes the outward diffusion of vapor-phase chemicals from impacted soil or groundwater ...
 
...transport includes the outward diffusion of vapor-phase chemicals from impacted soil or groundwater and the potential advective flow of the vapors ...
 
...chemicals from impacted soil or groundwater and the potential advective flow of the vapors into an overlying building (Figure 7 1). The chemicals could migrate to and intrude residential ...
 
...migrate to and intrude residential or commercial/industrial building interiors. Common vapor intrusion pathways into buildings include basements, crawl spaces, cracks, and utility penetrations ...
 
... crawl spaces, cracks, and utility penetrations in concrete slabs. The intruding vapors subsequently mix with indoor air and the concentration of initial chemicals in the vapors ...
 
...subsequently mix with indoor air and the concentration of initial chemicals in the vapors is attenuated. Figure 7-3: Complete Exposure ...
 
... Figure 7-3: Complete Exposure Pathway CSM for Soil Vapor to Indoor Air. A more detailed conceptual model of soil vapor transport ...
 
...to Indoor Air. A more detailed conceptual model of soil vapor transport might consider spatial temporal variations in subsurface conditions and building ...
 
... Brewer et al. 2014, in prep). This factor and uncertainty regarding specific, vapor entry routes complicates the investigation of potential vapor intrusion hazards. As discussed ...
 
...entry routes complicates the investigation of potential vapor intrusion hazards. As discussed in Section 7.6.2.2, the biased collection of subslab ...
 
...hazards. As discussed in Section 7.6.2.2, the biased collection of subslab soil vapor samples from center of slabs, presumed to be the worst-case area for vapor accumulation as ...
 
...samples from center of slabs, presumed to be the worst-case area for vapor accumulation as well as potential vapor entry points in other areas of the building (e.g., ...
 
...accumulation as well as potential vapor entry points in other areas of the building (e.g., cracks in floor and utility gaps) is recommended. ...
 
...as daughter products). These conditions could change over time, as the release ages. The vapor transport of daughter products, oxygen, CO2, and in the case of petroleum hydrocarbons, methane, ...
 
...aerobic or anaerobic biodegradation processes. The exposure pathway for soil vapor should be included on the CSM, which serves as the basis of an exposure assessment (see HDOH, ...
 
...the chemicals of concern. An example of a complete exposure pathway CSM diagram for soil vapor to indoor air is provided in Figure 7-3. For the chemicals of concern ...
 
...present a means of exposure under the conditions assumed in the CSM. Common pathways for vapor intrusion from the subsurface are cracks or utility penetrations through the slab or basement ...
 
...Bathrooms, kitchens and utility rooms are often the primary entry points for intruding vapors. As discussed in Sections 7.6.2 and 7.10.1, it is important that ...
 
...prepared prior to an investigation and used to help determine the number and location of vapor collection points as well as the frequency and timing of sample collection. See ...
 
...7.14 discusses the use of a multiple-lines-of-evidence approach to evaluate potential vapor intrusion hazards on a site-specific basis for cases where a high risk of vapor intrusion is ...
 
...intrusion hazards on a site-specific basis for cases where a high risk of vapor intrusion is identified. ...
 

7.3 Characterization, Delineation and Monitoring
... ' 7.3 DEVELOPMENT OF VAPOR INTRUSION SCREENING TOOLS Assumptions regarding the local nature of vapor intrusion ...
 
...INTRUSION SCREENING TOOLS Assumptions regarding the local nature of vapor intrusion and building ventilation can be used to develop environmental action levels for rapid ...
 
...screening of suspect sites. Development of the HDOH soil, groundwater and soil gas (�vapor�) action levels for vapor intrusion is discussed in the HDOH EHE guidance document (HDOH ...
 
...action levels for vapor intrusion is discussed in the HDOH EHE guidance document (HDOH 2016; see also HDOH, 2016b.). ...
 
...study entitled Field Investigation of the Chemistry and Toxicity of TPH in Petroleum Vapors: Implications for Potential Vapor Intrusion Hazards (HDOH, 2012). The results of this ...
 
...Implications for Potential Vapor Intrusion Hazards (HDOH, 2012). The results of this study were incorporated ...
 
...the EHE guidance, the selected attenuation factors and associated HDOH action levels for vapor intrusion may not be adequately conservative for use in colder regions on the US mainland and ...
 
...the US mainland and elsewhere. Adjustment of the action levels to assumptions regarding vapor flux and building ventilation is required and should be discussed with the overseeing regulatory ...
 

7.4 Soil Vapor Probe Installation
... ' 7.4 SOIL VAPOR INVESTIGATIONS The following subsections discuss the collection and analysis of ...
 
... The following subsections discuss the collection and analysis of soil vapor and indoor air samples. Although the guidance presented is anticipated to apply under ...
 
...and should be discussed with the overseeing HDOH project manager. Soil vapor samples, including samples collected immediately beneath building slabs, are collected following ...
 
...or groundwater. Data are used for general site-characterization purposes and/or to assess vapor intrusion risk. Typical site investigation objectives include: 1) Characterization of in situ ...
 
...risk. Typical site investigation objectives include: 1) Characterization of in situ vapor plume conditions, 2) Assessment of potential vapor intrusion risks, 3) Assessment of worker-related ...
 
...plume conditions, 2) Assessment of potential vapor intrusion risks, 3) Assessment of worker-related environmental hazards in locations where soil ...
 
...risks, 3) Assessment of worker-related environmental hazards in locations where soil vapor may accumulate (e.g., utility conduits or vaults beneath foundations, roadways and caps, 4) ...
 
...of remedial actions. Indoor air samples are collected as needed to further assess vapor intrusion risk and link or negate identified impacts to a subsurface source. Soil vapor data ...
 
...intrusion risk and link or negate identified impacts to a subsurface source. Soil vapor data can also be used to assess potential impacts to groundwater posed by downward migrating ...
 
...can also be used to assess potential impacts to groundwater posed by downward migrating vapors or volatile chemicals dissolved in downward migrating leachate (refer to HDOH 2017b). ...
 
... in downward migrating leachate (refer to HDOH 2017b). The types of soil vapor samples collected and subsequent use of the data can vary based on the objective(s) of the ...
 
...points beneath a building or in open areas and representing very small volumes of vapor (e.g., one to six liters) can be useful for identification of large-scale, vapor plume patterns. ...
 
...(e.g., one to six liters) can be useful for identification of large-scale, vapor plume patterns. Reliance on individual sample points to identify plume boundaries or assess ...
 
...patterns. Reliance on individual sample points to identify plume boundaries or assess vapor intrusion risk is complicated, however, by the inherent variability of VOC concentrations in ...
 
...risk is complicated, however, by the inherent variability of VOC concentrations in vapors at this small scale. The collection of �Large Volume Purge (LVP)� samples, representing thousands ...
 
...The collection of �Large Volume Purge (LVP)� samples, representing thousands of liters of vapor, is recommended when feasible in order to improve data reliability (Section 7.8.5). ...
 
...order to improve data reliability (Section 7.8.5). Testing of soil vapor is carried out through the collection of �active� or �passive� vapor samples from multiple ...
 
...is carried out through the collection of �active� or �passive� vapor samples from multiple points within the targeted investigation area and comparison of the resulting ...
 
...area and comparison of the resulting data to HDOH Environmental Action Levels (EALs) for vapor intrusion risk (HDOH 2017a). �Active� samples are collected by drawing vapor into ...
 
...intrusion risk (HDOH 2017a). �Active� samples are collected by drawing vapor into canisters under a vacuum (Section 7.8.1) or by drawing vapor through a sorbent tube ...
 
...into canisters under a vacuum (Section 7.8.1) or by drawing vapor through a sorbent tube (Section 7.8.2). �Passive� samples are collected by burying ...
 
... 7.8.3). Small-volume, active samples(e.g., 1-6 liters) that minimize disturbance of a vapor plume and/or passive samples are used to characterize undisturbed, in situ subslab vapor conditions. ...
 
...plume and/or passive samples are used to characterize undisturbed, in situ subslab vapor conditions. Large-volume, active sample data are used to more reliably assess actual vapor ...
 
...conditions. Large-volume, active sample data are used to more reliably assess actual vapor intrusion risk. Although useful for general screening purposes, note that data for small-volume ...
 
...passive, are in theory not directly comparable to HDOH (2017a) action levels for vapor intrusion risk. The action levels more strictly apply to the mean concentration of a VOC in ...
 
...levels more strictly apply to the mean concentration of a VOC in very large volumes of vapor assumed to intrude a building over many years, amounting to millions of liters of vapor per ...
 
...assumed to intrude a building over many years, amounting to millions of liters of vapor per year (refer to Section 13.2; see also Brewer et al. 2014). ...
 
... to Section 13.2; see also Brewer et al. 2014). The use of LVP vapor sampling methods is recommended for more direct evaluation of vapor intrusion risk. This approach ...
 
...sampling methods is recommended for more direct evaluation of vapor intrusion risk. This approach allows for a very large, risk-based volume of vapor to be represented ...
 
...intrusion risk. This approach allows for a very large, risk-based volume of vapor to be represented by a single, active soil vapor sample (Section 7.8.5). The resulting ...
 
...to be represented by a single, active soil vapor sample (Section 7.8.5). The resulting data will thus be more directly representative of ...
 
...The resulting data will thus be more directly representative of the large volume of vapor predicted to intrude into a building on a given day, for example the 3,000-liter, default, ...
 
...into a building on a given day, for example the 3,000-liter, default, assumed daily vapor entry rate for buildings in Hawai�i discussed in Section 7.5.5. This method is currently ...
 
...Section 7.5.5. This method is currently most widely applied to the collection of subslab vapor data. The collection of deep LVP samples from areas with a thick vadose zone is feasible for ...
 
...samples from areas with a thick vadose zone is feasible for soils with a relatively high vapor permeability, provided that monitoring for leakage to outdoor air is carried out. The collection ...
 
...provided in this section is intended to apply to sites in the State of Hawai`i where soil vapor and, if required, indoor air samples are collected, whether the evaluation is being conducted ...
 
...technically defensible and consistent approach for the collection and evaluation of soil vapor or indoor air samples. However, this guidance is not regulation and is only meant to provide ...
 
...is only meant to provide a clear technical framework for collecting and evaluating soil vapor or indoor air samples. The information contained in this guidance is not intended to exclude ...
 
...efforts to prevent fires or explosions resulting from the accumulation of hazardous vapors (i.e., methane); however, methane concentrations should be monitored to determine whether ...
 
...actions by qualified responders should be completed prior to the initiation of a soil vapor or indoor air sampling event. If the results from the soil vapor or indoor air sampling event ...
 
...or indoor air sampling event. If the results from the soil vapor or indoor air sampling event indicate that there is an immediate concern for human exposures ...
 
...air sampling event indicate that there is an immediate concern for human exposures to vapor phase chemicals, then emergency response or interim actions are typically implemented as required ...
 
... under state and federal regulations. The HEER Office recommends that Soil Vapor or Indoor Air sampling work plans be submitted for review and approval prior to the collection ...
 
...sampling work plans be submitted for review and approval prior to the collection of soil vapor or indoor air samples in Hawai`i. The work plan should describe the purpose and rationale ...
 
...samples in Hawai`i. The work plan should describe the purpose and rationale for the soil vapor or indoor air sampling, targeted chemicals of concern, sample locations and depths, sample ...
 

7.5 Soil Vapor Or Indoor Air Sampling Methods
... ' 7.5 COLLECTION OF REPRESENTATIVE SOIL VAPOR SAMPLES The basic concepts of site investigation design and data collection and ...
 
... discussed in Section 3 and Section 4 of this guidance apply to soil vapor and indoor air as well as of soil and sediment. A systematic approach (Section 3.3) should ...
 
...the work plan prepared for the site investigation. The interpretation of soil vapor and indoor air data is discussed in Section 7.14. It is important that data be collected ...
 
...small-volume samples collected from single points can be compared to HDOH subslab vapor action levels for initial identification of large-scale, subsurface vapor plumes that could ...
 
...action levels for initial identification of large-scale, subsurface vapor plumes that could pose potential vapor intrusion concerns (HDOH 2017b; see also Section ...
 
...plumes that could pose potential vapor intrusion concerns (HDOH 2017b; see also Section 7.14.1). Random, small-scale variability ...
 
... see also Section 7.14.1). Random, small-scale variability of VOC concentrations within a vapor plume (e.g., at the scale of a one-liter vapor sample) can, however, lead to erroneous estimates ...
 
...plume (e.g., at the scale of a one-liter vapor sample) can, however, lead to erroneous estimates of vapor plume boundaries (“false ...
 
... sample) can, however, lead to erroneous estimates of vapor plume boundaries (“false negatives”) and estimation of vapor intrusion risk (Section 13.2; ...
 
...plume boundaries (“false negatives”) and estimation of vapor intrusion risk (Section 13.2; see also Brewer et al. 2014). Small-scale, “hot spot” ...
 
...“hot spot” and “cold spot” VOC patterns based on single samples within a large vapor plume can likewise be artifacts of random variability and very misleading of actual site ...
 
... conditions. Although useful for initial screening purposes, HDOH soil vapor action levels for vapor intrusion apply to the mean or “true” concentration of a targeted VOC ...
 
...action levels for vapor intrusion apply to the mean or “true” concentration of a targeted VOC for the total volume ...
 
...apply to the mean or “true” concentration of a targeted VOC for the total volume of vapor anticipated to intrude a building over several years. Comparison of deep soil vapor data or ...
 
...anticipated to intrude a building over several years. Comparison of deep soil vapor data or data for small-volume samples collected immediately beneath a slab can useful for initial ...
 
...useful for initial screening purposes but is not strictly appropriate for evaluation of vapor intrusion risk (refer to Section 13.2). This is similar to limitations on comparison of small-volume, ...
 
... b). Assumptions regarding the representativeness of small-volume vapor sample data should be used with other lines of evidence to assess long-term, vapor intrusion ...
 
...sample data should be used with other lines of evidence to assess long-term, vapor intrusion risk. This includes the nature of known releases, soil data (preferably MIS; ...
 
...soil data (preferably MIS; Section 4), groundwater data and Large Volume Purge (LVP) vapor data collected directly beneath the slab, as discussed below and in Section 7.4. ...
 
... used to assess the risk posed by contaminated soil is required to reliably assess vapor intrusion risk (see Section 3.4). The results of the Site Scoping (Section 3.1) and Systematic ...
 
...3.2) should be used to designate slab areas within the subject building for subslab vapor sample collection. This could include testing of subslab vapors: Beneath ...
 
...sample collection. This could include testing of subslab vapors: Beneath known or hypothetical, vapor entry points; Within known or suspect ...
 
... Beneath known or hypothetical, vapor entry points; Within known or suspect subslab utility trenches that could serve as preferential ...
 
...or suspect subslab utility trenches that could serve as preferential pathways for vapor flow; Above suspect soil or groundwater source areas; Beneath areas of the building ...
 
...absence of other information; Beneath the center of the building slab or other potential vapor accumulation areas beneath the slab. An indoor air study (Section ...
 
...air study (Section 7.7) can in some cases be used to identify the general location of vapor entry points. In most cases, however, vapor entry points (if present) are rarely known during ...
 
...entry points. In most cases, however, vapor entry points (if present) are rarely known during the initial stages of an investigation. As ...
 
...rarely known during the initial stages of an investigation. As an alternative, subslab vapor samples for assessment of vapor intrusion risk are typically drawn from hypothetical entry ...
 
...samples for assessment of vapor intrusion risk are typically drawn from hypothetical entry points in worst-case areas ...
 
...in worst-case areas of the slab. A risk-based DU volume of soil vapor should be designated for sample collection, similar to the approach used for characterization ...
 
...estimate the true (“mean”) concentration of targeted VOCs within this targeted volume of vapor. A default, DU vapor volume of 3,000 liters is recommended for use in Hawai´i. This represents ...
 
...A default, DU vapor volume of 3,000 liters is recommended for use in Hawai´i. This represents the volume of subslab ...
 
...of 3,000 liters is recommended for use in Hawai´i. This represents the volume of subslab vapor assumed to intrude a building through a single gap in a floor over a one-day period, based ...
 
... a building through a single gap in a floor over a one-day period, based on a daily vapor entry rate of 2 L/minute. The same vapor entry rate is used to calculate subslab soil vapor ...
 
...entry rate of 2 L/minute. The same vapor entry rate is used to calculate subslab soil vapor action levels presented in the HDOH EAL ...
 
...entry rate is used to calculate subslab soil vapor action levels presented in the HDOH EAL guidance (HDOH 2017a) and is predicted to be appropriate ...
 
...to be appropriate for tropical climates (Brewer et al. 2014). Larger subslab vapor DU volumes are appropriate for non-tropical climates due to potentially higher, vapor entry ...
 
...DU volumes are appropriate for non-tropical climates due to potentially higher, vapor entry rates during periods when a building is being heated. The following vapor entry rates ...
 
...entry rates during periods when a building is being heated. The following vapor entry rates are estimated for different climate zones by Brewer et al. (2014): ...
 
... Estimated Annual-Average Vapor Entry Rate (L/min) Estimated ...
 
... Estimated Annual-Average Vapor Entry Rate (L/day) Cold ...
 
... 365 0 2.0 2,880 The daily vapor entry rate estimated for tropical climate zones, rounded to 3,000 liters/day, was referenced ...
 
...climate zones, rounded to 3,000 liters/day, was referenced for use as a default subslab vapor volume for LVP sample collection. Note that an LVP DU volume of 7,000 liters was used in the ...
 
...of LVP samples in cold climate zones. As a default, subslab vapor in soil or fill material within 15-25cm of the building slab should be targeted for sample ...
 
...of the building slab should be targeted for sample collection. For example, screened, vapor extraction points might be installed to a depth of 15cm beneath the slab and a series of 3,000-liter, ...
 
...might be installed to a depth of 15cm beneath the slab and a series of 3,000-liter, LVP vapor samples collected. Characterization of targeted vapor DUs could in theory be accomplished ...
 
...samples collected. Characterization of targeted vapor DUs could in theory be accomplished by collection of an “adequate” number of small-volume vapor ...
 
...DUs could in theory be accomplished by collection of an “adequate” number of small-volume vapor sample points. The number of samples required to obtain a representative concentration of the ...
 
...of samples required to obtain a representative concentration of the targeted VOCs in the vapor and use of the resulting data to assess vapor intrusion risk is uncertain, however. ...
 
... and use of the resulting data to assess vapor intrusion risk is uncertain, however. Use of individual data points is not strictly appropriate, ...
 
... Use of individual data points is not strictly appropriate, since the small volume of vapors represented cannot be assumed to represent vapors intruding the building or even the general ...
 
...represented cannot be assumed to represent vapors intruding the building or even the general concentration of VOCs in vapors in the immediately ...
 
...intruding the building or even the general concentration of VOCs in vapors in the immediately surrounding area (see Section 13.2). Statistical analysis can be used ...
 
...analysis can be used to estimate a mean concentration for a set of small-volume, vapor sample data points, but the total volume of vapor directly represented by the samples will ...
 
...sample data points, but the total volume of vapor directly represented by the samples will again be very small in comparison to the DU volume ...
 
...represented by the samples will again be very small in comparison to the DU volume of vapors of interest. The field representativeness of a single set of small-volume, vapor points cannot ...
 
...of interest. The field representativeness of a single set of small-volume, vapor points cannot be directly assessed in the absence of multiple, replicate sets of individual ...
 
...in Section 4.3. Sample data that represent large, risk-based volumes of vapor (e.g., thousands of liters), similar to the concept of “Multi Increment” soil sample data (Section ...
 
...(Section 4) are required for more reliable characterization of subsurface vapor plumes and vapor intrusion risk. Such “LVP” methods are currently mostly widely used for testing ...
 
...plumes and vapor intrusion risk. Such “LVP” methods are currently mostly widely used for testing of ...
 
... intrusion risk. Such “LVP” methods are currently mostly widely used for testing of vapors beneath building slabs where breakthrough to indoor air can be minimized (Section 7.8.5). ...
 
... (Section 7.8.5). The collection of LVP samples helps ensure that isolated, subslab vapor “hot-spots” that might be missed by small-volume vapor samples are incorporated into the data ...
 
...“hot-spots” that might be missed by small-volume vapor samples are incorporated into the data used to assess potential vapor intrusion risk and provides ...
 
...samples are incorporated into the data used to assess potential vapor intrusion risk and provides a volume-weighted average vapor concentration more applicable ...
 
...intrusion risk and provides a volume-weighted average vapor concentration more applicable to comparison with subslab vapor action levels (HDOH 2017a; ...
 
...concentration more applicable to comparison with subslab vapor action levels (HDOH 2017a; Section 7.14.1). Direct correlation of LVP data to identified ...
 
...might still not be practical, given the typical lack of knowledge of the exact point of vapor entry into a building, if in fact this is occurring. ...
 

7.6 Soil Vapor Sample Collection Procedures
... ' 7.6 SOIL VAPOR SAMPLING STRATEGIES 7.6.1 Determining When to Collect Soil Vapor Samples ...
 
...SAMPLING STRATEGIES 7.6.1 Determining When to Collect Soil Vapor Samples Table 7-1 Decision Logic for Subsurface Vapor Hazards ...
 
...Samples Table 7-1 Decision Logic for Subsurface Vapor Hazards ...
 
... Soil Vapor Data ...
 
... Contaminants in Vadose Zone 2Soil and/or 3Groundwater Pose Potential Vapor Intrusion Hazards ...
 
... Collect source area vapor data and data to evaluate potential vapor intrusion hazards. ...
 
...data and data to evaluate potential vapor intrusion hazards. ...
 
... Collect source area vapor data to evaluate potential future vapor intrusion hazards or, at a minimum, ...
 
...data to evaluate potential future vapor intrusion hazards or, at a minimum, recommend soil vapor investigation prior ...
 
...intrusion hazards or, at a minimum, recommend soil vapor investigation prior to future subsurface work or construction of buildings. ...
 
... Post-Remediation Confirmation of Previously Identified Vapor Intrusion Hazard ...
 
... Collect soil vapor data to confirm and document absence of remaining, significant vapor intrusion ...
 
...data to confirm and document absence of remaining, significant vapor intrusion hazards. ...
 
... 4No Potentially Significant Vapor Intrusion Hazards Identified ...
 
... Collection of soil vapor samples not necessary; conclude in EHE that contamination does not pose significant ...
 
...necessary; conclude in EHE that contamination does not pose significant vapor intrusion hazards. ...
 
... VOC concentrations above Tier 1 soil action levels for vapor intrusion, significant volume (e.g., >10m3) of VOC-contaminated soil is present, ...
 
...(e.g., >10m3) of VOC-contaminated soil is present, or potential for elevated vapors under a building slab otherwise suspected (e.g., PCE vapors under a dry cleaner). ...
 
...under a building slab otherwise suspected (e.g., PCE vapors under a dry cleaner). Free product on groundwater table or dissolved ...
 
...table or dissolved VOC concentrations above Tier 1 groundwater action levels for vapor intrusion. VOC concentrations below Tier 1 EALs for both soil or groundwater ...
 
... >10m3) of VOC-contaminated soil or other potential source of elevated vapors under a building slab not suspected. An example, decision flow chart ...
 
... An example, decision flow chart for the collection of soil vapor samples is presented in Table 7-1. Soil vapor samples are collected to help locate and characterize ...
 
...samples is presented in Table 7-1. Soil vapor samples are collected to help locate and characterize areas of contaminated soil and groundwater ...
 
...to help locate and characterize areas of contaminated soil and groundwater that pose vapor intrusion risks for existing or future buildings. Direct comparison of groundwater data to ...
 
...Direct comparison of groundwater data to HDOH action levels intended to address potential vapor intrusion concerns in the absence of initial, soil vapor (or indoor air) data is generally ...
 
...intrusion concerns in the absence of initial, soil vapor (or indoor air) data is generally acceptable (HDOH 2017a). The groundwater action levels ...
 
...are collected. If action levels are exceeded then the additional collection of soil vapor samples is recommended. If a significant threat to indoor air is deemed likely, then the concurrent ...
 
...in the models and data used to develop the levels. The direct collection of soil vapor samples is recommended in these scenarios. Reliance on soil samples to adequately ...
 
...number of �hot spots� is minimal. The chemicals may also be present predominantly in vapor phase in very dry soil (e.g., beneath a dry cleaner building slab). This could be overlooked ...
 
...by the collection of only soil samples. The collection of soil vapor samples is therefore recommended at all sites where a significant amount of VOC-contaminated ...
 
...be present in the vadose-zone and/or the contaminant could be present primarily in the vapor phase. A soil volume of at least 10m3 is generally needed in order to pose significant, long-term ...
 
...soil volume of at least 10m3 is generally needed in order to pose significant, long-term vapor intrusion hazards, based on mass-balance models for assumed exposure duration and ...
 
...short-term, acute or nuisance impacts must also be considered. Direct collection of soil vapor samples regardless of soil and/or groundwater data is also recommended for sites with a very ...
 
...tend to more evenly disperse over relatively large areas due to diffusion flow. A soil vapor sample is also representative of a significantly larger volume of soil (liters) than ...
 
...sample (five grams, around three milliliters). This emphasizes the usefulness of soil vapor samples to identify the presence or absence of significant VOC contamination in the subsurface. ...
 
...small but still significant areas of VOC-contaminated soil that might pose leaching or vapor intrusion hazards. Even so, and as discussed elsewhere in this section and in Section ...
 
...be considerable and limits the reliability of data that represent very small volumes of vapor. Although not explored in detail in this guidance document, soil vapor data can ...
 
... Although not explored in detail in this guidance document, soil vapor data can also be used to evaluate leaching hazards at sites contaminated with volatile chemicals. ...
 
...in vadose-zone leachate can be made by simply dividing the concentration of the VOC in vapor samples by the Henry�s Constant (unitless) for that chemical. This approach is used to develop ...
 
...the Henry�s Constant (unitless) for that chemical. This approach is used to develop soil vapor screening levels for leaching and groundwater protection concerns in the Tropical Pacific edition ...
 
...guidance (HDOH 2017b). Additional guidance on the use of soil vapor samples to help evaluate potential leaching hazards at sites will be included in future editions ...
 
...TGM. In addition to the identification of subsurface VOC-contaminated soil, subsurface vapor samples are most commonly used to evaluate potential vapor intrusion hazards for existing ...
 
...samples are most commonly used to evaluate potential vapor intrusion hazards for existing or future buildings. The HEER Office recommends the following ...
 
...HEER Office recommends the following three-step approach for the initial evaluation of vapor intrusion hazards at sites where soil or groundwater is contaminated with volatile chemicals ...
 
...in Appendix 1 of the EHE document; or use the EAL surfer. Collect soil vapor samples immediately beneath building slab (preferred; LVP sampling methods recommended) ...
 
...LVP sampling methods recommended) or adjacent to buildings if groundwater EALs for vapor intrusion are approached or exceeded or if a potentially significant source of VOCs in ...
 
...Section 7.6.2.2; see also HDOH, 2016, Table C-2 in Appendix 1). Collect soil vapor samples from within deeper, source areas if widespread, heavy contamination is known to ...
 
...heavy contamination is known to be present (see Section 7.6.2.3). Collect soil vapor samples beneath the footprint of anticipated, future buildings if a building is not currently ...
 
...include sealing of floors and active treatment of source areas or the installation of vapor barriers under future buildings. Consider the collection of indoor air samples if the concentration ...
 
... Consider the collection of indoor air samples if the concentration of a VOC in vapors immediately beneath a building slab exceeds the soil gas action level and ...
 
... Table 7-1 provides the decision logic for determining when soil vapor sampling is recommended (Step 2) based on the occurrence of VOCs in soil and/or groundwater ...
 
...the building and the source area. The initial collection of soil vapor samples will generally focus on source area and immediately under overlying or nearby buildings. ...
 
...from a subsurface source area is considered adequate to prevent potentially significant vapor intrusion problems (ITRC 2007). The adequate vertical separation distance is highly site and ...
 
...and contaminant specific. Vertical separation distances appropriate for attenuation of vapors associated with chlorinated solvents have not been adequately studied. ...
 
...of sediment, etc., can lead to the presence of clay-rich moist units with very low vapor permeability that significantly impede the upward diffusion of vapors (diffusion rates through ...
 
...permeability that significantly impede the upward diffusion of vapors (diffusion rates through water are typically four orders-of-magnitude slower than through ...
 
...EHE guidance, HDOH, 2016). Thin lenses of perched groundwater can further reduce upward vapor flux. Aerobic biodegradation of non-chlorinated, vapor-phase, petroleum compounds can also ...
 
...flux. Aerobic biodegradation of non-chlorinated, vapor-phase, petroleum compounds can also result in a significant and often abrupt attenuation of ...
 
...petroleum compounds can also result in a significant and often abrupt attenuation of vapors within a few feet of a source area (e.g., heavily contaminated soil or free product on groundwater). ...
 
...ten meters (thirty feet) of clean soil (i.e., TPH <100 mg/kg) is adequate to reduce vapor concentrations to below levels of concern for potential vapor intrusion hazards, regardless ...
 
...concentrations to below levels of concern for potential vapor intrusion hazards, regardless of the mass or concentration of petroleum in underlying soil ...
 
...these separation distances can be used to determine the need to collect actual soil vapor samples at a site. For example, if no contaminated soil is present in the upper thirty ...
 
...soil is present in the upper thirty feet of the vadose zone then potentially significant vapor intrusion hazards can be ruled out without the collection of soil gas samples. If the water ...
 
... on groundwater and contaminated soil is not present in the vadose zone, then potential vapor intrusion hazards can again be ruled out without the collection of soil vapor samples. ...
 
...intrusion hazards can again be ruled out without the collection of soil vapor samples. Shorter vertical separation distances might be appropriate, but should ...
 
...a site-specific basis before a concurrence to negate the need to collect additional soil vapor samples can be granted. This should include borings to characterize subsurface soil types and ...
 
... to characterize subsurface soil types and the collection of a small number of soil vapor samples (e.g., one to three) from an area considered to be representative of overall site conditions. ...
 
...to be representative of overall site conditions. In practice, significant long-term vapor intrusion hazards are unlikely to be posed by dissolved-phase petroleum contaminants in groundwater ...
 
... under any site scenario due to low source strength and rapid biodegradation of vapors in the vadose zone. The collection of soil vapor samples over dissolved-phase plumes ...
 
... in the vadose zone. The collection of soil vapor samples over dissolved-phase plumes can, however, help negate (or identify) the presence of ...
 
... petroleum contamination in the vadose zone. (For dissolved-phase solvent plumes, soil vapor samples are always strongly recommended if action levels for vapor intrusion are approached ...
 
...samples are always strongly recommended if action levels for vapor intrusion are approached or exceeded, regardless of the depth of the plume.) ...
 
...should be evaluated on a site-by-site basis. Significant, lateral migration of petroleum vapors away from source areas is of particular concern at sites covered with pavement or buildings, ...
 
... product on shallow groundwater (i.e., <30ft deep) could lead to the accumulation of vapors under caps and a progressive outward expansion of anaerobic conditions and migration of petroleum ...
 
...and a progressive outward expansion of anaerobic conditions and migration of petroleum vapors over time. Exceptions to the above guidelines are likely to be rare, but could ...
 
...that could allow for significantly greater vertical and lateral migration of petroleum vapors prior to attenuation below target action levels. Other potential exceptions include substantial ...
 
...natural replenishment of oxygen is overwhelmed. Anaerobic conditions and less inhibited vapor migration could also develop under paved areas that overlie deep (i.e., >30ft) widespread, ...
 
...Soil and Groundwater HDOH, 2007c). 7.6.2 Soil Vapor Sampling Design 7.6.2.1 Overview The design of a soil ...
 
...Design 7.6.2.1 Overview The design of a soil vapor sampling plan should reflect the objectives of the investigation. Investigations are typically ...
 
...of the investigation. Investigations are typically carried out to identify large-scale vapor plume patterns vs vapor intrusion assessment. Factors considered in the design of a soil vapor ...
 
...plume patterns vs vapor intrusion assessment. Factors considered in the design of a soil vapor investigation include ...
 
...intrusion assessment. Factors considered in the design of a soil vapor investigation include the objectives of the investigation, soil type, depth to groundwater, ...
 
...and regulatory requirements. Small-volume (e.g., one-liter) soil vapor samples are typically used for in situ characterization of subsurface vapor plumes (see Section ...
 
...samples are typically used for in situ characterization of subsurface vapor plumes (see Section 7.2). Large-scale patterns implied by the data can be used to ...
 
...are less reliable, due to potential random variability of VOC concentrations within a vapor plume at the scale of a few liters or less. The use of Large Volume Purge (LVP) methods for ...
 
...of a few liters or less. The use of Large Volume Purge (LVP) methods for collection of vapor samples immediately beneath building slabs and more direct assessment of vapor intrusion ...
 
...samples immediately beneath building slabs and more direct assessment of vapor intrusion risk are discussed separately in Section 7.5 and Section 7.8.5. The collection ...
 
... and Section 7.8.5. The collection of one or more LVP samples to initially assess vapor intrusion risk is appropriate for general due diligence purposes, especially in absence of ...
 
...of known or suspect, vadose-zone source area. The collection of multiple, small-volume vapor samples for in situ characterization of large-scale, vapor plume patterns is recommended if ...
 
...samples for in situ characterization of large-scale, vapor plume patterns is recommended if localized source areas are known or suspected beneath a building ...
 
...can then be used to designate LVP sample collection points for more direct evaluation of vapor intrusion risk. As discussed below, soil vapor sampling locations are selected ...
 
...intrusion risk. As discussed below, soil vapor sampling locations are selected based on areas the CSM identifies as having the potential for ...
 
...vertical delineation considerations. Following the selection of sample locations, soil vapor samples can be collected using temporary driven probes or by installing permanent soil vapor ...
 
...samples can be collected using temporary driven probes or by installing permanent soil vapor sampling probes (see Section 7.9). When assessing the source of subsurface vapors, samples ...
 
...sampling probes (see Section 7.9). When assessing the source of subsurface vapors, samples are typically collected within the suspected or known source area, and upgradient, ...
 
...area, and upgradient, downgradient, and cross-gradient of the source area because soil vapor can migrate in a different direction than groundwater flow. When assessing upward, vertical ...
 
...a different direction than groundwater flow. When assessing upward, vertical migration, vapor samples from multiple depths may be useful or even required to evaluate upward attenuation ...
 
...from multiple depths may be useful or even required to evaluate upward attenuation of vapors or highlight the need to identify preferential pathways through otherwise low-permeability ...
 
...buildings. As also discussed in more detail below, the frequency of soil vapor sampling is dependent upon the purpose of the soil vapor investigation. Characterization and ...
 
...sampling is dependent upon the purpose of the soil vapor investigation. Characterization and delineation can require one or two surveys, while remediation ...
 
...does not address safety or hazard mitigation efforts required in the event of explosive vapor accumulation (i.e., methane); however, methane concentrations should be monitored to determine ...
 
...as the Lower Explosive Limit [LEL] for methane). At contaminated sites, additional soil vapor sampling events and possible interim corrective measures should be considered if methane exceeds ...
 
...exceeds 1/10 of the LEL (see Section 9.4). 7.6.2.2 Soil Vapor Sampling Point Locations Figure 7-4: Schematic ...
 
...Locations Figure 7-4: Schematic of Soil Vapor Concentration Profile. VOCs volatilize out of a groundwater plume and diffuse vertically ...
 
...VOCs volatilize out of a groundwater plume and diffuse vertically toward the surface. Vapor phase concentrations are highest at the groundwater-vadose zone interface and decrease ...
 
...highest at the groundwater-vadose zone interface and decrease with decreasing depth. Vapors can accumulate under buildings or paved areas as the ability to diffuse outward and be ...
 
...point samples are used during the initial phase of investigation to identify large-scale vapor plume patterns and initially estimate potential vapor intrusion risks to overlying, existing, ...
 
...plume patterns and initially estimate potential vapor intrusion risks to overlying, existing, or future buildings. A relatively small number ...
 
...risks to overlying, existing, or future buildings. A relatively small number of soil vapor samples (e.g., three to ten) are typically used to initially identify the presence or absence ...
 
...areas or immediately above suspect groundwater sources. The additional collection of soil vapor samples from the fill material immediately under the building slab is recommended for initial ...
 
... attenuation of VOCs away from a source area. (Note that reliable correlation between vapor points will be limited by uncertainty regarding the magnitude of random, small-scale variability ...
 
...by uncertainty regarding the magnitude of random, small-scale variability within the vapor plume). Confirmation of the plume boundaries based on multiple points is necessary to avoid ...
 
...negatives and under estimation of the overall plume size. The location and shape of a vapor plume might not mimic the shape of the primary source area (i.e., contaminated soil or groundwater). ...
 
...contaminated soil or groundwater). This is because the outward, lateral migration of vapors away from the source area is strongly influenced by small-scale heterogeneities in the soil ...
 
...obvious in the field. In the experience of the HEER Office, high concentration areas of vapor plumes can be located some distance from the primary source area, complicating identification ...
 
...from the primary source area, complicating identification of the latter based on soil vapor data alone. Locations for soil vapor sampling should be selected based ...
 
...data alone. Locations for soil vapor sampling should be selected based on the objectives of the investigation. If the objective ...
 
...the objectives of the investigation. If the objective is to identify and map large-scale vapor plume patterns, then strategically located sampling points over and around the suspected ...
 
... future use of the site. Care should be taken to avoid utilities when collecting vapor samples within or nearby utility corridors. If the objective of the investigation ...
 
...corridors. If the objective of the investigation is to assess potential vapor intrusion impacts at an existing building, then targeted sampling locations at the building, ...
 
... at an existing building, then targeted sampling locations at the building, at the vapor source, and possibly in-between may be appropriate. Grids of passive soil vapor samples should ...
 
...source, and possibly in-between may be appropriate. Grids of passive soil vapor samples should also be considered (see Section 7.8.3 and see Section 7.12). The collection ...
 
...(see Section 7.8.3 and see Section 7.12). The collection of small-volume soil vapor samples from immediately beneath building foundations (i.e., below the concrete slab or within ...
 
...slab or within crawl spaces) can also assist in subsequent designation of LVP subslab vapor points for more direct assessment of potential vapor intrusion risk (Section 7.8.5). ...
 
...points for more direct assessment of potential vapor intrusion risk (Section 7.8.5). For example, LVP samples could be collected directly ...
 
...directly within high-concentration areas of a plume in order to assess worst-case, vapor intrusion conditions. In contrast, LVP samples might be collected from localized, low-concentration ...
 
...from localized, low-concentration areas within a plume suspected to indicate active vapor intrusion, as less-impacted air is advectively drawn into this area of the plume. ...
 
...this area of the plume. Note that dry soil under slabs can serve to enhance vapor concentrations in comparison to soils with a higher moisture content, even though the total ...
 
...corridors may be warranted, since coarse fill in the trenches can serve as a conduit for vapors to the slab as well as to utility penetrations and other potential preferential pathways through ...
 
... considered if the source of contamination is not below the building or the collection of vapor samples directly beneath the building is limited due access issues or the presence of subsurface ...
 
...for shallow water tables) in order to take into consideration the potential buildup of vapors under existing or future building slabs. Small-volume soil vapor sample ...
 
...under existing or future building slabs. Small-volume soil vapor sample data for in situ characterization of a subslab vapor plume can be collected above suspect ...
 
...sample data for in situ characterization of a subslab vapor plume can be collected above suspect sources areas beneath the building slab, in the ...
 
... the vicinity of utility corridors that could serve as preferential pathways for vapor migration, beneath high-risk areas of the building based on use or penetrations in the slab ...
 
...of the building slab (USEPA 2012d; CalEPA 2011; see Section 7.7.2). Vapor points also should be placed in the vicinity of the building where vapor intrusion is considered ...
 
...points also should be placed in the vicinity of the building where vapor intrusion is considered to be most likely, as well as between the center of the building and ...
 
...7.7.2).The number of probes that can be installed for in situ characterization of a vapor plume will in part be limited by cost and logistical considerations, including accessibility ...
 
...utilities. As discussed above, the type of chemicals present in the soil vapor should also be considered in selecting soil vapor sampling locations. Biodegradation can play ...
 
...should also be considered in selecting soil vapor sampling locations. Biodegradation can play an important role in the subsurface migration of ...
 
...petroleum-related contaminants and can significantly reduce the concentration of VOCs in vapors over short distances. At sites where the chemicals of concern are chlorinated compounds (e.g., ...
 
...of VOCs can persist for significant distances. Elevated concentrations of VOCs in soil vapors can also persist for long periods of time in the vadose zone following active, in situ remediation ...
 
...vadose zone following active, in situ remediation of contaminated groundwater (�residual vapor plume,� see Table 7-1). The San Diego County Site Assessment and Mitigation ...
 
...and Mitigation (SAM) Manual, among other references, provides a useful source of soil vapor sampling strategies for a variety of site scenarios (SDC 2011). ...
 
... strategies for a variety of site scenarios (SDC 2011). 7.6.2.3 Soil Vapor Sample Depths and Depth Intervals The depth of soil vapor points depends on the ...
 
...Sample Depths and Depth Intervals The depth of soil vapor points depends on the objectives of the investigation (Figure 7-4). Characterization of known or suspected ...
 
... the subsurface geology and the depth to groundwater. The investigation of potential vapor intrusion hazards will require the placement of sample points within shallow, vapor flow pathways, ...
 
...intrusion hazards will require the placement of sample points within shallow, vapor flow pathways, including utility trenches and fill material immediately beneath slabs (e.g., ...
 
...of soil beneath building slab). Ideally, the lateral and vertical extent of vapor plumes should be delineated to HDOH Tier 1 soil vapor action levels applicable to residential ...
 
...plumes should be delineated to HDOH Tier 1 soil vapor action levels applicable to residential land use (HDOH, 2016). Small-volume sample ...
 
... uncapped areas and the potential for breakthrough to outdoor air. Less conservative soil vapor action levels may be appropriate for assessment of vapor intrusion risk at commercial/industrial ...
 
...action levels may be appropriate for assessment of vapor intrusion risk at commercial/industrial sites. Failure to compare site data to residential ...
 
...a land use restriction on the site, however. The collection of small-volume vapor samples and/or LVP samples from the fill material immediately beneath a building slab (e.g., ...
 
...beneath a building slab (e.g., first 6 to 12 inches of soil) is an important part of a vapor intrusion investigation. Relatively permeable, sandy silts are typically used as fill material ...
 
...slabs to provide structural stability. This fill material is often more permeable to vapors than the native, clayey soils in Hawai�i and can serve as a preferential pathway for subsurface ...
 
...native, clayey soils in Hawai�i and can serve as a preferential pathway for subsurface vapors via connecting utility trenches or other conduits. Soil vapor samples ...
 
...via connecting utility trenches or other conduits. Soil vapor samples should therefore always be collected in the fill material immediately beneath the slab ...
 
...be collected in the fill material immediately beneath the slab for evaluation of current vapor intrusion hazards, even if deeper samples are also collected. A focus on deeper soil vapor ...
 
...intrusion hazards, even if deeper samples are also collected. A focus on deeper soil vapor sample data can be misleading, since the samples do not take into account upward attenuation ...
 
...soils might be relatively un-impacted, even though the concentrations of VOCs in vapors within the fill material are extremely high. This is a common scenario for dry cleaners, ...
 
...presence of a building slab or other paving also significantly slows, or prevents, soil vapor from diffusing upwards and escaping to the atmosphere. This can result in elevated soil vapor ...
 
...from diffusing upwards and escaping to the atmosphere. This can result in elevated soil vapor VOC concentrations beneath the slab/paving in comparison to adjacent, uncovered areas. Note, ...
 
...concentrations under the slab than at the source. The collection of soil vapor samples from both the fill material immediately under the building slab and the suspected or ...
 
... 7.9.3 and 7.10.1). Small-volume sample data can be used to assess large-scale, vapor plume patterns. The collection of LVP sample data is recommended for more direct assessment ...
 
...patterns. The collection of LVP sample data is recommended for more direct assessment of vapor intrusion risk (Section 7.8.5). This will help assess the need to seal cracks and ...
 
...floor as an added measure of precaution, in the event that nearby portions of the vapor plume exceed subslab soil vapor action levels, even though the measured concentrations of volatile ...
 
...plume exceed subslab soil vapor action levels, even though the measured concentrations of volatile chemicals in actual soil ...
 
...levels, even though the measured concentrations of volatile chemicals in actual soil vapor do not, and potential preferential pathways into the building were overlooked (se Section 7.14.1). ...
 
... HDOH 2007c). In other cases additional monitoring to verify that adverse, vapor intrusion impacts are unlikely to occur will be needed (see Section 7.10.1). This ...
 
...(see Section 7.10.1). This will typically require the periodic collection of LVP vapor samples beneath targeted areas of the slab, similar to the collection of periodic samples from ...
 
... wells. Reliance on small-volume samples might, however, be required for monitoring of vapors beneath building slabs that cannot be sufficiently sealed for LVP sample collection. The collection ...
 
...the building slab, although this would likewise reduce the risk of advective flow of vapors into the building. Collection depths for small-volume sample data to be used to ...
 
...building. Collection depths for small-volume sample data to be used to assess vapor intrusion risk in open areas where LVP sample data are not practical depends in part on the ...
 
... VOCs present. At sites with recalcitrant compounds (e.g. chlorinated solvents) soil vapor samples should be collected from no less than five feet below ground surface. Soil vapor samples ...
 
...samples should be collected from no less than five feet below ground surface. Soil vapor samples collected from depths of less than five feet can underestimate the concentrations of ...
 
...of recalcitrant compounds that could accumulate if a building were present. Soil vapor samples should be collected from a minimum depth of ten feet for petroleum-contaminated sites ...
 
...table. This is necessary in order to take into consideration the potential buildup of vapors under existing or future building slabs due to low-oxygen conditions and a reduced potential ...
 
... focus. In some cases it may also be desirable to assess the vertical distribution of vapor-phase contaminants between the source media and the ground surface or the foundation of a building. ...
 
...should also be considered when identifying sampling depths. In general, installation of vapor sampling probes in relatively high permeability horizons is preferred; however, the overall ...
 
...preferred; however, the overall CSM should be taken into account as well. Permanent soil vapor probes should be installed above the maximum-anticipated, seasonally- or tidally-influenced ...
 
... or tidally-influenced elevation of the water table. 7.6.2.4 Soil Vapor Sample Screen Intervals Screens used for subslab samples should match the thickness ...
 
... immediately beneath the slab, typically four to six inches. Both small-volume and LVP vapor samples are typically collected though a temporary or permanent six-inch (15cm) screen or �implant.� ...
 
...Longer screening might be warranted for more reliable characterization of large-scale, vapor plume patterns. As discussed above and in Section 7.8.5, data for small volumes of vapor can ...
 
...plume patterns. As discussed above and in Section 7.8.5, data for small volumes of vapor can be useful for identification of large-scale plume patterns but are not necessarily ...
 
... of large-scale plume patterns but are not necessarily pertinent to assessment of vapor intrusion. This is similar to issues related to the use of discrete sample data for very general ...
 
... soil sample data to more directly evaluate risk. Six- to twelve-inch vapor point screens are generally desirable for characterization of subslab vapors, since HDOH soil ...
 
...point screens are generally desirable for characterization of subslab vapors, since HDOH soil vapor action levels are intended to apply to vapors within the assumed narrow, ...
 
...since HDOH soil vapor action levels are intended to apply to vapors within the assumed narrow, advective zone in ...
 
...action levels are intended to apply to vapors within the assumed narrow, advective zone in the immediate vicinity of a vapor entry point. ...
 
...within the assumed narrow, advective zone in the immediate vicinity of a vapor entry point. Much longer screens might be desirable for in situ, larger-scale characterization ...
 
...might be desirable for in situ, larger-scale characterization of deeper portions of a vapor plume. For example, a five-foot (1.5m) length of a two inch-diameter (15 cm) well screen contains ...
 
...30 liters of air. Allowing the air inside of the well screen to equilibrate with vapors in the surrounding soil would allow a sample collected from the well screen to represent ...
 
...would allow a sample collected from the well screen to represent a much larger volume of vapor than the vapor actually captured within a canister. The resulting data would provide a more ...
 
...than the vapor actually captured within a canister. The resulting data would provide a more reliable and reproducible ...
 
...and reproducible characterization of the plume at that specific location in terms of vapor intrusion risk. Replicate samples could be collected over time to assess data precision and ...
 
...could be collected over time to assess data precision and temporal variability within the vapor plume. Note that the same is true with respect to the representativeness of a groundwater ...
 

7.7 Indoor Air Sample Collection Procedures
... Although counterintuitive, testing of indoor air to identify and evaluate potential vapor intrusion concerns is fraught with potential error and generally discouraged except in cases ...
 
...fraught with potential error and generally discouraged except in cases where subslab soil vapor data indicate a clear threat to indoor air (see HDOH, 2016). This is due to the common presence ...
 
...2016). This is due to the common presence of the same suite of targeted VOCs in soil vapor in indoor air from sources within or outside of the building (e.g., USEPA 2011e). ...
 
...levels for many common chemicals. Correlation of indoor air data with subsurface, soil vapor data can therefore be difficult if not impossible if the concentration of VOCs identified in ...
 
...background. Although precautionary measures could be taken to mitigate potential vapor intrusion (e.g., sealing of floors, improved ventilation, etc.), as a general rule a home or ...
 
...etc.), as a general rule a home or building should not be flagged for potential vapor intrusion hazards unless this is supported by multiple lines of evidence, including indoor ...
 
...or near the building (i.e., from outdoor air and not the subsurface). Assessments of vapor intrusion should consider the following factors: ...
 
...urban houses. HDOH, 2016; indoor action level equal to sum of vapor-phase, TPH aliphatic and aromatic compounds (see Section 7.11). ...
 
...90th percentile. Indoor air sources (other than soil vapor); Outdoor air sources (other than soil vapor); Location and characteristics ...
 
... Outdoor air sources (other than soil vapor); Location and characteristics of known or suspected soil vapor source; ...
 
... Location and characteristics of known or suspected soil vapor source; Building ventilation and air exchange rate; Building materials ...
 
...used household products contain some of the same compounds of concern as targeted in vapor intrusion investigations (e.g., TPH and BTEX from cleaners and fuels, PCE from dry-cleaned ...
 
... levels. For these reasons, testing of indoor air to evaluate potential vapor intrusion impacts is generally discouraged unless concentrations of targeted chemicals in subslab ...
 
... is generally discouraged unless concentrations of targeted chemicals in subslab soil vapor are more than one-thousand times typical indoor air concentrations for residences and two-thousand ...
 
...2016). Indoor air sampling may also be warranted if field screening of potential vapor pathways inside of a building suggest that vapors could be impacting indoor air at levels significantly ...
 
...pathways inside of a building suggest that vapors could be impacting indoor air at levels significantly above background and the pathways are ...
 
...CalEPA 2011, New York State DOH 2006). The evaluation of potential vapor intrusion hazards and decisions regarding the need for remedial actions will instead, in most ...
 
...actions will instead, in most cases, focus on subslab or crawl space data. Shallow soil vapor data or data for samples collected under paved areas can be taken into consideration for sites ...
 
...for sites without existing buildings. Subslab (including sub-basement) soil vapor samples should be collected for buildings with a slab-on-grade construction. For buildings ...
 
... with a slab-on-grade construction. For buildings with a crawl space design, shallow soil vapor samples should be collected adjacent to the building in addition to samples from the crawl ...
 
...in addition to samples from the crawl space. In both cases, it is preferable that soil vapor and/or crawl space samples be collected prior to collection of indoor air samples and ...
 
...the need to collect the latter (see HDOH 2016). If a significant source of potential vapors is present below the building (e.g., petroleum free product on shallow groundwater) then the ...
 
...petroleum free product on shallow groundwater) then the collection of source area soil vapor samples is also recommended (see Sections 7.6.2). Together, subslab and source area data ...
 
...of data should be carried out under the direction and oversight of HDOH. Soil vapor (or crawl space) samples should be collected at the same time in order to assist in the interpretation ...
 
... Section 7.14). Indoor air data should never be used as the only line of evidence for vapor intrusion. Indoor air data should be compared to both risk-based screening levels ...
 
...concentrations. More than one round of sampling is recommended if a significant source of vapors is identified beneath a building (see Section 7.11.3). If representative concentrations ...
 
...within the range of anticipated background concentrations then active measures to address vapor intrusion are not necessary (see Section 7.14.2) , although sealing of cracks and gaps ...
 
...plan. Sources can include, but are not limited to, subsurface contamination (i.e., vapor intrusion), indoor sources (i.e., use/storage of VOC containing chemicals), and outdoor ...
 
... air should be considered in developing a sampling strategy. Common pathways for vapor intrusion from the subsurface are cracks or utility penetrations through the slab or basement ...
 
...earthen floors, and drain pipes. Elevator shafts could also serve as pathways for vapor intrusion, although these structures tend to mimic chimneys by conducting air out of rather ...
 
...tend to mimic chimneys by conducting air out of rather than into buildings, including vapors that might intrude into the bottom area of the shaft. Bathrooms, kitchens and utility ...
 
...kitchens and utility rooms are often the primary entry points for intruding vapors. VOCs can also enter a building through the heating, ventilation, and air conditioning ...
 
...air conditioning system is operating, due to the inflow of fresh air, dilution of vapors from indoor sources and the reduction of subsurface vapor intrusion when the building ...
 
...from indoor sources and the reduction of subsurface vapor intrusion when the building is over pressurized. Indoor air quality will be lowest when ...
 
...in Hawai�i) to outside wind effects that could induce an upward flow of subsurface vapors. Occupants: The presence and activities of building occupants can ...
 
...identify the location, duration, and frequency of indoor air sampling. As with soil vapor sampling strategy, location, duration, and frequency will be influenced by site-specific conditions ...
 

7.8 Soil Vapor or Indoor Air Sample Analysis
... 7.8 SAMPLING APPROACHES AND EQUIPMENT The collection of soil vapor or indoor air samples can be more involved and complex than soil or groundwater sample collection. ...
 
...to the need for special sampling equipment and containers to address the reactivity of vapor-phase chemicals and the need to prevent leaks during sample collection. ...
 
...collection. Based on the type of sampling equipment and containers, soil vapor or indoor air sampling approaches can be grouped into the following categories: (1) whole air ...
 
...reported. Sorbent tube sampling involves drawing a specified volume of soil vapor or indoor air through a sorbent material using a pump or other vacuum source and analyzing ...
 
...by dividing the mass of the compounds collected on the sorbent material by the volume of vapor or air drawn through the sampler. If reanalysis of a sample might be required, then a collection ...
 
... on the sampler is then measured. Flux chambers are traditionally used to measure vapor emission rates from point sources such as waste ponds. Their use in soil vapor investigations ...
 
...emission rates from point sources such as waste ponds. Their use in soil vapor investigations is more limited but in some instances can be beneficial. A comparison ...
 
... inexpensive passive sampling can be used to initially screen a site for shallow vapor plumes and assist in the identification of areas for active soil vapor sampling. For the investigation ...
 
...plumes and assist in the identification of areas for active soil vapor sampling. For the investigation of vapors associated with releases of diesel and other middle ...
 
...sampling. For the investigation of vapors associated with releases of diesel and other middle distillate fuels, a combined used of both ...
 
...recommended during the planning phase for each project requiring the collection of soil vapor or indoor air samples. Equipment that could come in contact with a vapor sample ...
 
...or indoor air samples. Equipment that could come in contact with a vapor sample should be cleaned or decontaminated between samples to avoid cross contamination by ...
 
... Table 7-3 Comparison of Soil Vapor & Indoor Air Sampling Approaches ...
 
... Cannot directly measure vapor concentration ...
 
... Estimation of vapor concentrations possible, multiple samplers can be combined for analysis, ...
 
... Currently costly to install, cannot directly measure vapor concentration ...
 
... Does not measure in-situ concentrations, identification of vapor emission points difficult ...
 
... Table 7-4 Common Soil Vapor Concentration Unit Conversion Factors ...
 
...Lower photo: Single sorbent tube connected to a 60ml syringe for collection of vapor sample (see also Figure 7-27). ...
 
... Figure 7-10 Two Examples of Passive Soil Vapor Sample Collectors. ...
 
...of TCE and PCE Results for Passive Diffusion Sampler and Active Soil Vapor Sample ...
 
... Figure 7-13 Summary of high-density, passive sampler data for PCE vapors beneath the slab of a former dry cleaner: a) True data resolution based on PCE mass ...
 
... Figure 7-14. Designation of soil vapor DU beneath a building slab for collection of LVP samples; recommended default DU volume ...
 
...recommended default DU volume of 3,000 liters represents the default, daily vapor entry rate used to develop HDOH (2017a) soil vapor action levels for ...
 
...entry rate used to develop HDOH (2017a) soil vapor action levels for vapor intrusion risk. ...
 
...action levels for vapor intrusion risk. ...
 
...Example options for designation of purge points for collection of LVP subslab vapor samples: A) High-risk occupancy room within building; B) Subslab utility trench and ...
 
...preferential pathway; C) High-concentration area based on result of small-volume vapor sample data; D) Center of slab. ...
 
... Figure 7-19. Installation of LVP vapor extraction point used in HDOH (2017c) field study: a) Circular saw used to cut eight-inch ...
 
...a) Circular saw used to cut eight-inch hole in concrete for installation of vapor point and protective casing (latter not normally included); b) Completed hole; c) Two-inch ...
 
...casing (latter not normally included); b) Completed hole; c) Two-inch PVC vapor point; d) Completed vapor point (interior sealed with cement grout). A smaller diameter ...
 
...point; d) Completed vapor point (interior sealed with cement grout). A smaller diameter hole will normally be ...
 
...grout). A smaller diameter hole will normally be adequate for a two-inch soil vapor point. ...
 
...obtained using sorbent tubes and TO-17 analytical methods, although the volume of air or vapor drawn through the tubes is limited by the sorptive capacity of the media used. Individual laboratories ...
 
...whole-air methods (e.g., Air Toxics 2012). Whole air sampling (or other active soil vapor sampling) is recommended to quantify concentrations of vapor-phase chemicals for an exposure ...
 
...sampling) is recommended to quantify concentrations of vapor-phase chemicals for an exposure or risk assessment. Contaminant concentrations can be quantified ...
 
... Table 7-4 presents other common unit conversion factors and HDOH has developed a Vapor Unit Conversion spreadsheet that converts between concentrations and is available for download ...
 
...target compounds conducive to whole air sampling are chemically stable and have a vapor pressure greater than 0.1 torr at 25 ˚ C and 760 millimeters of mercury (one atmosphere). ...
 
...millimeters of mercury (one atmosphere). Effective recovery of chemicals from active soil vapor samples depends on sample humidity, chemical activity of the sample matrix, and the sample ...
 
...a stainless steel container that is placed under a vacuum and then used to collect a soil vapor or air sample. The canister is cleaned internally using electropolishing and chemical deactivation ...
 
...an interior surface that is nearly chemically inert. This minimizes reactions with the vapor sample and maximizes recovery of volatile compounds from the container. Recovery is generally ...
 
...samples (e.g., eight to twenty four-hours). Smaller canisters are typically used for soil vapor samples, for which screening levels are typically several orders of magnitude higher than for ...
 
...are typically several orders of magnitude higher than for indoor air. Collection of vapor samples greater than one-liter can be problematic as well as time consuming at sites with relatively ...
 
...with relatively tight soils. HDOH recommends a minimum sample size of one-liter for soil vapor samples in order to assist in the collection of data that are representative of the site ...
 
...decision making purposes. General procedures when planning a soil vapor investigation using Summa canisters include: Obtain the field ...
 
... Flow controllers (or flow restrictors) are essential equipment for the collection of vapor samples with Summa canisters. The controllers limit the rate at which a sample can be drawn ...
 
... Doing so could potentially strip VOCs from free product or sorbed to soil and bias the vapor sample collected. Older flow controllers tend to be bulky, less reliable and increase the chance ...
 
...cases, they may come preset and pre-attached to the Summa canister. A vacuum gauge at the vapor collection point is used to monitor the vacuum pulled during the collection of LVP vapor samples ...
 
...collection point is used to monitor the vacuum pulled during the collection of LVP vapor samples (Section 7.8.5). The analytical laboratory providing the ...
 
...(i.e., 10% of canisters) is recommended for standard TO-14 or TO-15 analysis for soil vapor or other applications where very low detection levels are not required. This is appropriate ...
 
...for routine ambient air applications and the collection of high-concentration soil vapor and landfill gas samples where parts-per-million or parts-per-billion reporting levels are ...
 
...Tedlar bags are flexible, plastic bags that can be used for the collection of air or vapor samples with a syringe or a lung box. Tedlar bags can offer an inexpensive, screening tool ...
 
... two layers of Tedlar film sealed at the edges and containing a valve allowing for soil vapor or indoor air sample collection using a syringe or lung box . Tedlar is a trade name for a ...
 
...to 50% or less of their total capacity. As described in Section 7.10.4, soil vapor or indoor air samples are collected in Tedlar bags using a lung box or a glass syringe ...
 
...Tube Sampling Sorbent tube sampling involves drawing a known volume of soil vapor or air through a sorbent material using a pump or other vacuum source and analyzing the sorbent ...
 
...Concentration is calculated by dividing the mass of a targeted compound by the volume of vapor or air drawn through the sampler. Photographs of sorbent tubes and sorbent tube sampling trains ...
 
...below, sorbent tubes in combination with Summa canisters are recommended for testing of vapors associated with diesel and other middle distillate fuels if a significant (e.g., >10%) ...
 
...to use in the field. A low-flow pump or syringe is used to draw soil vapor or air through the sorbent over a pre-established time period. A maximum flow rate of 200 ml/minute ...
 
...larger volume, indoor or outdoor air samples. If a pump is used then the volume of soil vapor drawn through the tube is calculated by multiplying the average flow rate by the draw time. ...
 
...syringe draw time of no less than 15 seconds, for example, is recommended for a 50ml soil vapor sample. This is the maximum draw volume typically allowed by laboratories for collection of ...
 
...draw volume typically allowed by laboratories for collection of high-concentration soil vapor samples associated with petroleum in order to avoid saturation of the sorbent material in the ...
 
...of volatile compounds at some sites can significantly limit the volume of soil vapor that can be drawn through a sorbent tube without saturation of the sorbent material. Unlike ...
 
...target aromatic compounds and are not good indicators of total TPH levels in soil vapors without inclusion of a correction factor, since vapors are likely to be dominated by aliphatic ...
 
...without inclusion of a correction factor, since vapors are likely to be dominated by aliphatic compounds. This is especially important to consider ...
 
...compounds. This is especially important to consider for testing of aromatic-poor vapors from diesel fuel or other middle distillate fuels (refer to HEER Office petroleum vapor study; ...
 
...from diesel fuel or other middle distillate fuels (refer to HEER Office petroleum vapor study; HDOH, 2012). PID readings for similar vapor concentrations from gasoline ...
 
...study; HDOH, 2012). PID readings for similar vapor concentrations from gasoline versus diesel can be significantly lower for diesel. An FID can ...
 
...can also extinguish the FID flame. This can be an issue for screening of subsurface vapor associated with degrading petroleum releases. When possible, screening ...
 
...For heavily contaminated, petroleum-release sites in particular, the amount of soil vapor drawn through a sorbent tube might still be limited to volumes as small as 50ml. Smaller volumes ...
 
... Figure 7-9). If sorbent tubes are to be used in a high-concentration, soil vapor environment (e.g., to evaluate TPH in vapors associated with diesel-contaminated soil or groundwater) ...
 
...environment (e.g., to evaluate TPH in vapors associated with diesel-contaminated soil or groundwater) and the volume of vapors to be drawn ...
 
...associated with diesel-contaminated soil or groundwater) and the volume of vapors to be drawn is less than one liter then the concurrent collection of a one-liter or larger ...
 
...7.13). The Summa canister sample should be collected first to help ensure that the vapor point is adequately purged and to improve the representativeness of the sorbent tube sample. ...
 
... tubing and soil. Allow adequate time for the vacuum on the soil to dissipate with the vapor sampling point remaining closed. This could take several minutes for tight soils. The sorbent ...
 
...minutes for tight soils. The sorbent tube sampling train should then be connected, the vapor point re-opened, and the sample collected. After the sample is drawn, ...
 
... to the laboratory for analysis. The concentration of a targeted chemical in the original vapor is calculated as the mass of the chemical sorbed divided by the volume of vapor drawn through ...
 
...is calculated as the mass of the chemical sorbed divided by the volume of vapor drawn through the sorbent. The storage and holding time for sorbent tubes vary ...
 
...prior to analysis and help reduce analytical time and costs. Note that petroleum vapors are dominated by aliphatic compounds. PIDs primarily target aromatic compounds and are not ...
 
...target aromatic compounds and are not good indicators of total TPH levels in soil vapors without inclusion of a correction factor. This is especially important to remember for aromatic-poor ...
 
...of a correction factor. This is especially important to remember for aromatic-poor vapors from diesel fuel or other middle distillate fuels (refer to HEER Office petroleum vapor study; ...
 
...from diesel fuel or other middle distillate fuels (refer to HEER Office petroleum vapor study; HDOH, 2012). PID readings for similar vapor concentrations from gasoline versus diesel ...
 
...study; HDOH, 2012). PID readings for similar vapor concentrations from gasoline versus diesel can be significantly lower for the latter. A Flame ...
 
...different lab methods, the difference in the two, reported concentrations of TPH in the vapor samples will give some idea of the proportion of compounds greater than C12. As an alternative, ...
 
...Sampling Passive sampling involves using adsorbent materials to collect vapor phase chemicals without the use of a pump or Summa canister. The vapor is not induced to flow ...
 
...phase chemicals without the use of a pump or Summa canister. The vapor is not induced to flow over the adsorbent; instead the chemicals in the vapor passively contact ...
 
...is not induced to flow over the adsorbent; instead the chemicals in the vapor passively contact the adsorbent and adsorb to it. Both VOCs and SVOCs are captured by the adsorbent ...
 
...sufficiently on the adsorbent and the less-volatile SVOCs may not have sufficient vapor pressure to be detectable. Passive sampling approaches requires less equipment ...
 
... in the field than active sampling. Data for samplers can be used to identify vapor-phase chemicals for additional site characterizations and vapor intrusion studies (e.g., ...
 
... chemicals for additional site characterizations and vapor intrusion studies (e.g., USEPA 2009). These methods give a time-integrated measurement ...
 
...Passive sampling methods have also been used to estimate VOC concentrations in soil vapor. Calculation of the vapor concentration from passive sampling results is, however, ...
 
... Calculation of the vapor concentration from passive sampling results is, however, sometimes attempted by estimating ...
 
...passive sampling results is, however, sometimes attempted by estimating the volume of vapor that passes by the buried adsorbent during the burial time period and a vapor diffusion model. ...
 
...that passes by the buried adsorbent during the burial time period and a vapor diffusion model. Another method is to determine an uptake rate for the passive collector. At ...
 
...for the passive collector. At present, comparative studies between actively measured soil vapor concentrations and those estimated from passive sampling are at best within an order of magnitude ...
 
...an order of magnitude (e.g., USEPA 2009). Due to this uncertainty, passive soil vapor data are considered to give qualitative or semi-quantitative vapor concentration results and ...
 
...data are considered to give qualitative or semi-quantitative vapor concentration results and generally are considered a screening tool for soil vapor investigations. ...
 
...concentration results and generally are considered a screening tool for soil vapor investigations. An emerging exception could be the use of water-based passive samples, discussed ...
 
...passive sampling can be beneficial for the initial stages of site characterization or vapor intrusion studies. Advantages of passive sampling include: ...
 
...and to map plumes; Able to detect any contaminant that has an appreciable vapor pressure and can be adsorbed in sufficient quantity to determine relative presence or absence, ...
 
...of passive sampling include: Not useful for generating vertical vapor profiles unless sampling intervals can be effectively isolated; Actual vapor concentrations ...
 
...profiles unless sampling intervals can be effectively isolated; Actual vapor concentrations can only be estimated, limiting use of the method to screening, plume mapping, ...
 
...samplers can also be a problem Passive sampling can be applied to either soil vapor or indoor air. Although the principle is the same in application to these media, the sampling ...
 
... as described in the two sections below. 7.8.3.1 Passive Soil Vapor Sample Collectors Qualitative passive soil vapor sample collection involves placing ...
 
...Sample Collectors Qualitative passive soil vapor sample collection involves placing an adsorbent into the subsurface for a pre-specified exposure ...
 
... the subsurface for a pre-specified exposure period to allow the adsorption of soil vapor chemicals onto the adsorbent material. Compound uptake rates are not required to be known for ...
 
... based on sampling objectives and site conditions. Passive soil vapor sample collection involves placing an adsorbent into the subsurface for a known exposure period ...
 
... for a known exposure period (e.g., one to two weeks) to allow the adsorption of soil vapor chemicals onto the adsorbent material. Sample collection procedures are described in Section ...
 
...bottom, or in a fine wire mesh or polymeric material, to facilitate contact with the soil vapor but not the soil. Photographs of two vendor-supplied sample collectors are provided in ...
 
... Figure 7-10. Although the results are qualitative, passive soil vapor sampling can provide useful information when investigating subsurface vapor plumes or preferential ...
 
...sampling can provide useful information when investigating subsurface vapor plumes or preferential pathways for vapor intrusion studies. One evolving ...
 
...plumes or preferential pathways for vapor intrusion studies. One evolving approach is to subdivide a site into targeted Decision ...
 
...a site into targeted Decision Units (DU) for screening characterization. Active soil vapor sampling will be targeted for the DU with the highest, relative concentration of VOCs identified ...
 
...of this study, the results of passive diffusion samplers were compared to active soil vapor measurements. These studies showed that: The passive soil vapor sampling ...
 
...measurements. These studies showed that: The passive soil vapor sampling systems detected the same compounds in each sample as the active method, as well ...
 
...method did not detect. This performance characteristic suggests that the passive soil vapor sampling systems may detect VOCs that are at lower concentrations in the subsurface than ...
 
...detect VOCs that are at lower concentrations in the subsurface than the active soil vapor sampling method can detect and/or that the passive samples were able to better capture ...
 
...and/or that the passive samples were able to better capture temporal changes in vapor concentrations due to the longer exposure period. The results also indicated a ...
 
... The results also indicated a general, relative correlation between passive soil vapor sampling results and active method data (e.g., high or low). However, at high contaminant ...
 
...the passive samplers in heavily contaminated areas. Because the passive soil vapor sampling systems and the active method use different techniques to collect soil vapor samples, ...
 
...sampling systems and the active method use different techniques to collect soil vapor samples, it is not expected that the two methods will provide the same response or that ...
 
... material inside – the vial is capped with a gas-permeable membrane, which allows vapors to enter the vial but excludes any particulate matter in the air. As discussed ...
 
... 7.8.3.3 Emerging Technologies The field of soil vapor and indoor air passive sampling is rapidly developing. There are a number of technologies that ...
 
... The use of high-densities of passive samplers to characterize the in situ nature of vapor plumes beneath building slabs was evaluated in an HDOH (2017) investigation of a PCE vapor ...
 
...plumes beneath building slabs was evaluated in an HDOH (2017) investigation of a PCE vapor plume beneath the slab of a former dry cleaner. The approach involves the installation of multiple, ...
 
...points. This has significant implications regarding the reliability of small-volume vapor sample data to accurately delineate plume boundaries and variability within larger-scale plumes ...
 
...and at this point is necessarily site specific. Isopleth maps of the vapor plume identified beneath the dry cleaner in the HDOH field study are presented in Figure 7-13. ...
 
... to generate corresponding isopleths. While clearly superior to typical, small-volume vapor sample investigations, the practicality of installing large numbers of passive samples beneath ...
 
...sampler (PDS) has been developed by the USEPA Office of Research and Development for soil vapor characterization (Paul 2009). This sampler uses water as the media into which contaminants ...
 
...including more polar compounds. More reliable estimates of VOC concentrations in soil vapor may be possible. The PDS is constructed using a 40 ml VOA vial filled with de-ionized ...
 
...a 40 ml VOA vial filled with de-ionized water and with the Teflon septa replaced with a vapor-permeable membrane. The PDS is inserted into a custom-made messenger (hollowed-out plastic ...
 
...two-inch diameter, monitoring wells with a screened interval placed at the desired soil vapor depth interval. Figure 7-12 shows a schematic of the PDS and a photo of the sampler ...
 
...into the water-filled PDS until the water reaches equilibrium with the surrounding soil vapor. The PDS is recovered from the well after an appropriate equilibration period, typically ...
 
... to estimate the average, equilibrium concentration of the VOC in the surrounding soil vapor. Several comparative field studies of this technology in application to petroleum ...
 
...Table 7-5 lists the results of one study wherein PDS sampler results were converted to vapor concentrations using Henry’s Law and then compared to a collocated active (e.g., Summa) soil ...
 
...using Henry’s Law and then compared to a collocated active (e.g., Summa) soil vapor measurement. In this study, the PDS estimated concentrations of vapor-phase VOCs were consistently ...
 
...measurement. In this study, the PDS estimated concentrations of vapor-phase VOCs were consistently higher than those reported for the active samples for both PCE ...
 
...either: 1) A consistent error in conversion of dissolved-phase VOCs to equivalent vapor-phase VOCs and/or 2) The existence of subsurface spatial and/or temporal vapor “hot spots” ...
 
...VOCs and/or 2) The existence of subsurface spatial and/or temporal vapor “hot spots” that were captured by the PDS sampler due to their longer exposure time but missed ...
 
... to adjacent areas or for estimation of time-averaged VOC concentrations for use in vapor intrusion studies. Whether or not PDS samples can indeed be used to obtain a more representative ...
 
...can indeed be used to obtain a more representative picture of long-term subsurface soil vapor conditions at a site is still under investigation. 7.8.4 Large Volume ...
 
... 7.8.4 Large Volume Purge Sampling “Large Volume Purge (LVP)” soil vapor collection methods, referred to as “High Purge Volume” samples by McAlary et al. (2010), have ...
 
... Volume” samples by McAlary et al. (2010), have been used sporadically to assess vapor intrusion risk since the early 2000s but only casually mentioned in USEPA or state agency guidance ...
 
...agency guidance (e.g., CalEPA 2015). Under this approach an active or passive vapor sample is continuously collected from a stream of vapor being purged from a point installed ...
 
...sample is continuously collected from a stream of vapor being purged from a point installed into the bottom-floor slab of a building. Problems hindering ...
 
...of the approach included: 1) Lack of awareness of the limitations of traditional, soil vapor data (see Section 13.2), 2) Lack of a systematic approach to soil vapor investigations ...
 
...data (see Section 13.2), 2) Lack of a systematic approach to soil vapor investigations and designation of risk-based, “Decision Units (DUs)” of vapor for sample collection ...
 
...investigations and designation of risk-based, “Decision Units (DUs)” of vapor for sample collection and characterization, 3) Limited information on the engineering design ...
 
...and 4) Misplaced concerns regarding the need to identify the exact, subslab source of vapors purged during sample collection. These issues were evaluated in an HDOH ...
 
... These issues were evaluated in an HDOH field study of the collection of LVP vapor samples carried out in 2016 (HDOH 2017c). The use of high-density, passive ...
 
... of high-density, passive sampler installation to characterize the in situ nature of vapor plumes beneath building slabs and assist in designation of LVP sample collection locations ...
 
...presented is intended as an example only and is similar in nature to a standard, soil vapor extraction pilot test. It is anticipated that more efficient LVP sample collection methods ...
 
... 7.8.4.1 Investigation Objectives and LVP DU Designation Large Volume Purge vapor data are used to more directly assess potential vapor intrusion risk at existing buildings, ...
 
...data are used to more directly assess potential vapor intrusion risk at existing buildings, rather than characterization of in situ VOC concentrations ...
 
...risk at existing buildings, rather than characterization of in situ VOC concentrations in vapors beneath a slab (refer to Section 7.5). This should be clearly stated in the project ...
 
...in designation of an LVP sample collection point. A default, subslab vapor DU volume of 3,000 liters is recommended (Figure 7-14). This reflects a default vapor entry ...
 
...DU volume of 3,000 liters is recommended (Figure 7-14). This reflects a default vapor entry rate of 2 L/minute estimated by Brewer et al. (2014) for buildings in tropical climate ...
 
...series of five LVP purges is recommended. This is intended to reflect potential vapor intrusion through the designated LVP sample collection point over a five-day period and better ...
 
...five-day period and better capture large-scale variability of VOC concentrations within a vapor plume underlying a building slab. Collecting separate samples over a series of LVP purges also ...
 
...LVP sample collection points include: At or near suspect or known vapor entry points; Within or adjacent to known or suspect subslab utility trenches that could serve ...
 
...or suspect subslab utility trenches that could serve as preferential pathways for vapor flow; Directly above suspect, subsurface soil or groundwater source areas; and Sensitive-use ...
 
...or in the center of the slab (Figure 7-15). Existing small-volume vapor sample data might also be used to designate an LVP collection point, if available, although ...
 
...an LVP collection point, if available, although the collection in advance of small-volume vapor samples is not necessary unless a source area above groundwater is specifically suspected ...
 
... These structures could in theory compartmentalize and isolate individual pockets of vapor beneath a slab and should be taken into consideration for designation of sample collection ...
 
...collection point that the floor should be sealed can be estimated as the worst-case, vapor draw area with respect to the targeted, total DU purge volume. Assume, for example, that a ...
 
...beneath or nearby the selected sample point and could serve as a preferential pathway for vapor flow. Based on a total LVP purge volume of 15,000 liters (i.e., five, 3,000 liter purges) and ...
 
...effective, air-filled porosity of 28% (default value used in HDOH EAL calculations), the vapors will be drawn from an approximate 50 m3 volume of soil beneath the slab. This suggests that ...
 
...length of influence in both directions along the utility trench. The source area of the vapors cannot be determined from the purge data and will be influenced by preferential pathways ...
 
...the soil. Exact knowledge of the source area is not important for assessment of potential vapor intrusion risk but could be useful for identification of subslab source areas and/or utility ...
 
...and other features that could serve as preferential pathways. The source of purged vapors can be approximated by installing additional probe points through the slab and monitoring ...
 
...if significant levels of VOCs are reported in LVP samples and a better understanding of vapor source areas is needed, as discussed below. These distances are for example ...
 
... as part of LVP sample collection (Section 7.8.4.4). The exact vapor draw area does not need to be determined as part of an LVP investigation since, aside from ...
 
...aside from an increased flow rate, sample collection is intended to directly mimic upward vapor flow through the designated point. This includes potential leakage of outdoor air under the ...
 
...the edges of the slab during sample LVP purges. As discussed in Section 13.2, subslab vapors that intrude and impact indoor air in most cases originate as outdoor air that has been drawn ...
 
...slowly diffusing out of a soil or groundwater source as the air flows toward the vapor entry point. Knowledge of the approximate location of the vapor source area might, ...
 
...entry point. Knowledge of the approximate location of the vapor source area might, however, be beneficial as part of a follow-up characterization to identify ...
 
...data indicate potentially adverse impacts to indoor air. Be aware, however, that subslab vapor plumes are often not co-located with the soil or groundwater source area. An additional soil ...
 
...additional soil and/or groundwater investigation will typically be required to identify vapor source areas. Strategies for the investigation of soil and groundwater contamination by volatile ...
 
...an approach published by McAlary et al. (2010) and is similar to designs used for a soil vapor extraction pilot test. It is anticipated that the design utilized in the field study can be ...
 
...basic configuration consists of a two-inch polyvinyl chloride (PVC) pipe connected to a vapor sampling point installed in the center of the slab. A Shop-Vac® was used in the field study ...
 
...the field study to produce a vacuum on the sample point and purge the targeted volumes of vapors. Rotron or similar types of fans or blowers can also be utilized. Multiple sample ports should ...
 
...ports should be installed into the PVC piping to allow the vacuum on the well point and vapor flow rate to be monitored and ensure a continuous draw of a vapors from the purge stream into ...
 
...flow rate to be monitored and ensure a continuous draw of a vapors from the purge stream into or through the selected collection apparatus. In practice ...
 
...into or through the selected collection apparatus. In practice the volume of vapors purged and the mass of VOCs in the purge stream will be relatively small. The system should ...
 
...7-18 (Section 7.8.1). The system could also be designed to allow a continuous stream of vapors to pass through a sorbent collection tube (Section 7.8.2). No experience with the ...
 
...used at joints in the piping, if necessary to ensure secure fittings. If used, then the vapor purge system should be allowed to aerate for several days prior to use in the field and ...
 
...fittings. This will be similar to the shut-in test described in Section 7.10.5.1 for soil vapor sampling trains in general. Test the vacuum of the pump (e.g., Shop-Vac) to be used for sample ...
 
... of the system and evaluate the purge rate under different vacuums imposed on the vapor entry point. Ensure that the flow meter(s) are functioning properly. In the HDOH (2017c) field ...
 
...Verifying the precision of flow rate measurements is critical, since the DU volume of vapors purged per sample is a critical part of sample collection and data evaluation. ...
 
...al. 2010). Note that this is well below the maximum recommended vacuum to be applied to a vapor sample point of 100 in-H2O or seven inches of mercury (in-Hg), intended to avoid stripping ...
 
...point of 100 in-H2O or seven inches of mercury (in-Hg), intended to avoid stripping of vapors from free product entrained in soil (refer to Section 7.10.3.2; see also CalEPA ...
 
...1 to 10 minutes to collect an LVP sample from a default, 3,000 liter DU volume of subslab vapor. Smaller diameter piping will require a longer purge time for any given sub-slab permeability ...
 
...beneath the slab and prevents downward leakage of indoor air during purges of subslab vapor. In the HDOH (2017) LVP field study, the extraction point was constructed as a two-inch ...
 
... should be extended from the base of the concrete pad to the depth of targeted, subslab vapor DU (e.g., 12 inches). Include a solid endcap on the well point in order to help focus the draw ...
 
...of LVP sample collection are met. Alternative designs should ensure that collection of vapors from the targeted subslab DU interval is optimized, that leakage around the extraction point ...
 
...The test should be kept as short as possible in order to limit disturbance of subslab vapors. A duration of less than 60 seconds is anticipated to be adequate. Record ...
 
...the starting and final vacuum of the summa canister. Use this to estimate volume of the vapor sample collected in the canister. Discuss minimum sample volume necessary to meet testing requirements ...
 
...close the Summa canister valve (or port to sorbent tube) as well as the valve to the vapor extraction point. Disconnect the sample collection apparatus (e.g., Summa canister or sorbent ...
 
...other gases used to assess potential leakage in addition to VOCs targeted as part of the vapor intrusion investigation. 7.8.4.6 Data Quality Control ...
 
...(Section 7.10.5): 1) Shut-in test of LVP sampling train prior to and after connection to vapor extraction; 2) Leak testing of sampling train using isopropyl alcohol or comparable method ...
 
...4) Collection of O2, CO2 and other potential tracer gas data for preliminary subslab vapors prior to sample collection and as part of all LVP and background indoor air sample analyses; ...
 
...LVP sample. Test for and record oxygen and carbon dioxide levels in subslab vapors at the well point prior to the collection of LVP samples. These data will be important for ...
 
...in leakage tests (e.g., indoor air contaminants not anticipated to be present in subslab vapors). Evaluation of the overall integrity of the sampling train during LVP sample ...
 
...indoor air leakage into the sampling train during purge events. Oxygen levels in subslab vapors are often depleted in comparison with indoor (and outdoor) air. This is accompanied by a typical ...
 
...air. This is accompanied by a typical increase in carbon dioxide levels in subslab vapors. These observations and data can be used to assess the relative magnitude of ...
 
...sampling train during purge events. A leakage rate of 90% of sample volume represented by subslab vapors). An absence of significant isopropyl alcohol in the samples implies minimal leakage at these ...
 
...air but absent or at significantly depleted levels in pre-sample collection, subslab vapors might also prove very useful (e.g., TPH, BTEX, non-targeted solvents, etc.) ...
 
...and reproducibility is not necessary for continuously collected samples, since vapor from 100% of the purge stream is included in the resulting data (i.e., replicate samples not ...
 
...however, recommended for sample collection methods that involve only periodic testing of vapors from the purge stream. For example, a small “increment” of vapor might be allowed to enter ...
 
...from the purge stream. For example, a small “increment” of vapor might be allowed to enter the sample collection system (or field testing equipment) every minute ...
 
...or some fraction of a minute. In this case the resulting data represents the mean of the vapor increments collected and the representativeness of the complete purge stream cannot be directly ...
 
...Site background and summary of existing data; Rationale for targeted DU volume of subslab vapors to be characterized and selection of LVP sample collection point; Summary of ...
 
...of data for targeted VOCs; Investigation conclusions, including evaluation of potential vapor intrusion risks and any limitations on data reliability; Field photographs; ...
 
... ITRC 2007; Figure 7-21). Flux chambers were originally designed to estimate vapor emissions from open waste pits in terms of mass per unit area per unit time (e.g., mg/m2-hour). ...
 
...eliminates some of the assumptions required when using other types of subsurface data in vapor intrusion models. Unlike soil vapor or indoor air samples, flux chamber data can be used to ...
 
...intrusion models. Unlike soil vapor or indoor air samples, flux chamber data can be used to definitively identify and document ...
 
...flux chamber data can be used to definitively identify and document the emission of vapors from subsurface sources to the atmosphere or to the interior of buildings. The method has ...
 
...emissions from natural soils. HDOH considers its quantitative value for soil vapor and vapor intrusion assessments to be limited, and HDOH should be contacted prior to the use ...
 
...and vapor intrusion assessments to be limited, and HDOH should be contacted prior to the use of flux ...
 
...and HDOH should be contacted prior to the use of flux chambers in site investigations or vapor intrusion studies. Flux chambers are primarily useful as a qualitative tool to locate surface ...
 
...part to the small area tested and difficulty in capturing the heterogeneity of subsurface vapors, as well as short term temporal variations in downward versus upward vapor flux (e.g., due ...
 
...as well as short term temporal variations in downward versus upward vapor flux (e.g., due to changes in barometric pressure). Use in open areas also does not mimic vapor ...
 
...flux (e.g., due to changes in barometric pressure). Use in open areas also does not mimic vapor flux into buildings. The presence of small-scale, preferential pathways in soils (e.g., desiccation ...
 
...floor surfaces such as single family residences, because the primary entry points of soil vapor into the structure (cracks, holes, sumps, etc.) are often concealed by floor coverings, ...
 
...analyzer or on-site GC can be used to attempt to identify the primary locations of vapor intrusion. Regardless of the method used, enough chamber measurements should be ...
 

7.9 Gas Phase Sample Evaluation
... ' 7.9 ACTIVE SOIL VAPOR PROBE INSTALLATION ...
 
... Figure 7-22: Typical Temporary Soil Vapor Probe Typical temporary soil vapor probe, designed to be driven by a direct-push drill ...
 
...Probe Typical temporary soil vapor probe, designed to be driven by a direct-push drill rig. The probe tip components ...
 
... Figure 7-23: Installing a Temporary Soil Vapor Probe Using a Direct-Push Drill Rig After the probe is driven to the desired sampling ...
 
...of the boring, and creating a cavity in the soil that provides access to the soil vapor at the desired depth for sampling. The photograph on the right shows a temporary soil ...
 
...desired depth for sampling. The photograph on the right shows a temporary soil vapor sampling probe in place. ...
 
... Figure 7-24 Vapor Point Completions Left: Surface completion of flush-mounted well with valve installed. ...
 
... Figure 7-25 Typical Nested Permanent Soil Vapor Sampling Probes ...
 
... Figure 7-26 Installation of a Permanent Soil Vapor ProbeUpper left photo: Hand-augering the borehole. Upper right photo: Preparation of ...
 
...left photo: Hand-augering the borehole. Upper right photo: Preparation of soil vapor sampling point. Bottom left photo: Hydrating the bentonite seal. Tape used to measure ...
 
... of borehole, sand pack, and bentonite. Bottom right photo: Purging the completed vapor probe. Surface completion is a 9-inch length of 3-inch diameter Schedule 40 PVC pipe ...
 
... Figure 7-27 Schematic of Typical Sub-Slab Soil Vapor Sampling Probe (see also Figure 7-28 & 7-29). ...
 
... Figure 7-28 Sub-Slab Soil Vapor Sampling Probes Upper left photo: Drilling hole with hand-held rotary hammer drill. ...
 
...bentonite seal. Bottom Left: Temporary probe completion. Bottom Middle and Right: Vapor probe with Swagelok termination fitted to hole (note larger diameter hole near surface), ...
 
... Figure 7-29 Sub-Slab Soil Vapor Sampling Probes Left: Example dual Swagelock setup for connection of vapor point to ...
 
...Sampling Probes Left: Example dual Swagelock setup for connection of vapor point to collection device (see Figure 7-25 and Figure 7-28) Right: Tubing ...
 
...device (see Figure 7-25 and Figure 7-28) Right: Tubing from vapor point and collection device connected with a union joint. ...
 
... Figure 7-30: Installation of a Vapor Pin™ with a silicon sleeve directly into slab for collection of subslab vapor ...
 
...Pin™ with a silicon sleeve directly into slab for collection of subslab vapor samples (screw-on protective cap shown in photo to right). Sample collection tubing ...
 
... the base. The purpose of soil vapor probes is to provide access to subsurface soil vapor so that an active sample can be collected. ...
 
...probes is to provide access to subsurface soil vapor so that an active sample can be collected. Soil vapor probes must be properly installed ...
 
...so that an active sample can be collected. Soil vapor probes must be properly installed to collect representative soil vapor samples and to minimize ...
 
...probes must be properly installed to collect representative soil vapor samples and to minimize the effects of changes in barometric pressure, temperature, or breakthrough ...
 
...for development of conceptual site models, including an understanding subsurface vapor transport pathways and mechanisms, and for selecting vapor probe depths. ...
 
...transport pathways and mechanisms, and for selecting vapor probe depths. Permanent probes typically consist of small, inert tubing (e.g. 1/4-inch ...
 
...a larger vertical interval ((API 2005). This is especially important for subslab soil vapor samples, where the average concentration of VOCs within one-foot of the slab around preferential ...
 
...Figures 7-24 and Figure 7-25 present several examples of flush-mounted soil vapor points and a schematic diagram of vapor probe point designs. Approximately ...
 
...points and a schematic diagram of vapor probe point designs. Approximately 1 foot of dry granular bentonite should be placed ...
 
...is always installed first. Figure 7-26 depicts the installation of a permanent vapor probe using a hand auger. Permanent probes should be finished to preclude infiltration of water ...
 
...Surface completions of permanent probes typically include a fitting that allows for soil vapor sample collection and a gas tight valve at the surface when the probe is not in use. Flush ...
 
...7.8.4 for guidance on the installation of Large Volume Purge (LVP) subslab vapor samples. Temporary, small-volume vapor sample subslab probes are installed in a similar manner ...
 
...samples. Temporary, small-volume vapor sample subslab probes are installed in a similar manner as permanent probes. The probe consists ...
 
... with 6 to 12 inches of tubing above the surface with a 2-way valve to seal it. Deeper vapor points can also be set beneath buildings slabs to investigate source-area vapor concentrations ...
 
...points can also be set beneath buildings slabs to investigate source-area vapor concentrations (see Section 7.6.2.3). Reviewing as-built plans and screening proposed vapor ...
 
...concentrations (see Section 7.6.2.3). Reviewing as-built plans and screening proposed vapor points using GPR or similar methods to check for rebar and other potential obstacles to drilling ...
 
...contamination; and 4) in the vicinity of cracks and gaps in the building slab where vapor intrusion is considered to be most likely (see also USEPA 2012d, CalEPA 2011). Examples ...
 
...the building slab, or areas where cracks in the floor could serve as preferential vapor pathways. Traditional subslab probes are installed by drilling a hole of appropriate ...
 
...the threaded plug. Figure 7-28 & Figure 7-29 depict completions for subslab vapor points. Alternative approaches that can reduce the time, effort and cost of collecting ...
 
...approaches that can reduce the time, effort and cost of collecting subslab soil vapor samples are being developed. One example includes the “Vapor PinTM,” which is installed directly ...
 
...samples are being developed. One example includes the “Vapor PinTM,” which is installed directly into the floor slab and does not require the installation ...
 
...If used, then an equilibrium time of at least two hours following installation of the vapor point (including vapor pins) is recommended. 7.9.4 Soil Vapor Probe ...
 
...point (including vapor pins) is recommended. 7.9.4 Soil Vapor Probe Tubing ...
 
... pins) is recommended. 7.9.4 Soil Vapor Probe Tubing Inert, rigid-walled tubing, such as Teflon, nylon (e.g. Nylaflow), ...
 
...nylon (e.g. Nylaflow), or stainless steel should be used as the primary tubing for soil vapor sampling probes (Ouellette 2004, SDC 2011, USEPA 2009). Tests using these materials ...
 
...from ambient air or other sources. Avoid leaving tubing near open sources of vapors (e.g., fuel cans, cleaners, etc.) or near auto exhaust.. 7.9.5 ...
 
...fuel cans, cleaners, etc.) or near auto exhaust.. 7.9.5 Soil Vapor Probe Abandonment When soil vapor probes are no longer needed they should be properly ...
 
...Probe Abandonment When soil vapor probes are no longer needed they should be properly abandoned. Abandonment procedures for temporary ...
 

7.10 Documentation of Soil Vapor or Indoor Air Sampling
... ' 7.10 ACTIVE SOIL VAPOR SAMPLING PROCEDURES Table 7-6 Sand ...
 
... Figure 7-31: Soil Vapor Probe Purging Devices Upper photo: Disposable syringe with 3-way Luer valve (see also ...
 
...Tedlar bag. Vacuum is drawn on sealed lung box, causing the Tedlar bag to pull vapor from the collection point and fill. ...
 
...Summa canister sampling trains. Upper schematic: Diagram of Summa canister soil vapor sampling apparatus. Lower photo: Teflon tubing connected to flow controller with swage ...
 
... Figure 7-35: Example Soil Vapor Sample Collection Setups Upper photo: Battery powered sampling pump draws soil vapor ...
 
...Sample Collection Setups Upper photo: Battery powered sampling pump draws soil vapor through the Teflon tubing from the temporary soil vapor probe tip to the sample sorbent ...
 
...through the Teflon tubing from the temporary soil vapor probe tip to the sample sorbent tube. A restrictor device reduces the pump flow to ...
 
...type of sorbent tube media. Middle schematic and photo: TO-17 sorbent tube soil vapor sampling apparatus. Vapor point tubing connected to sorbent tube inlet with a union ...
 
...sampling apparatus. Vapor point tubing connected to sorbent tube inlet with a union and swage lock; pump or syringe ...
 
...(latter shown in photo). Lower left photo: Summa canister used to collect soil vapor from a permanent soil vapor point. The blue-bodied flow controller is laboratory-calibrated ...
 
...from a permanent soil vapor point. The blue-bodied flow controller is laboratory-calibrated to restrict sample ...
 
...Figure 7-36). Small Summas used to collect samples; large Summa used to purge vapor point. Dual vacuum gauges in each setup used to monitor Summa vacuum and vacuum at ...
 
... Source of leak at sampling train vs vapor point or annular seal cannot be determined (although successful shut-in ...
 
... Figure 7-36: Soil Vapor Sampling Trains Arranged for Shut-in Test (see also Figure 7-35) ...
 
..."Water Dam" Sealed to Floor with Inert Putty for Leak Testing Slab-mounted Vapor Point. After Cox-Colvin 2013, b. The water level is filled to a level ...
 
... 2013, b. The water level is filled to a level above the tubing connection to the vapor point and monitored during a vacuum test prior to and during sample collection. ...
 
... Figure 7-38: Shroud Over Vapor Probe Surface Completion. Upper Photo: System consists of shroud (blue bucket), industrial-grade ...
 
...set into a ring of Play-Doh on concrete base to provide a tighter seal around vapor point. Large Summa used to purge well point; smaller Summa used to collect sample (see ...
 
...into shroud and used as tracer to identify leaks in both sampling train and vapor probe annular seal. Upper left photo: Five-gallon bucket helium shroud placed over ...
 
... The descriptions of active soil vapor sampling procedures in the following sections are general in nature and reflect commonly accepted ...
 
...more appropriate depending on sampling objectives 7.10.1 Soil Vapor Sample Timing and Frequency Like sample location and depth, the timing and frequency ...
 
...investigation is to develop a CSM that reflects the representative, average subsurface vapor concentrations and vapor intrusion conditions over time and during normal building operation ...
 
...concentrations and vapor intrusion conditions over time and during normal building operation over a period of many years ...
 
...of assumed, long-term, average site conditions. The collection of soil vapor samples from both the fill material immediately under the building slab and the suspected or ...
 
...floor as an added measure of precaution, in the event that nearby portions of the vapor plume exceed subslab, soil gas action levels even though VOCs meet action levels in subslab ...
 
...the EHE overview, site-specific considerations regarding the timing and frequency of soil vapor sample collection include building HVAC system operation, seasonal weather variations and associated ...
 
...are recommended if the conceptual model identifies the VOC concentrations in source area vapors well above shallow soil gas action levels and the potential for significant, temporal fluctuations ...
 
...soil gas action levels and the potential for significant, temporal fluctuations in soil vapor concentrations and or the potential for advective flow of vapors into overlying buildings. ...
 
...concentrations and or the potential for advective flow of vapors into overlying buildings. Recommendations include: Collection and comparison of ...
 
...include: Collection and comparison of subslab soil vapor samples (or crawl space samples) during periods of the year when air conditioning is and ...
 
...summer versus winter months); Collection of deep and subslab soil vapor samples (or crawl space samples) during both the wet and dry season for sites where a significant ...
 
...vary dramatically over the year. The collection of seasonal soil vapor samples should be considered at sites where a substantial smear zone that could be exposed ...
 
...falling water tables is known or suspected to be present. The collection of subslab soil vapor samples during periods of both falling and rising water table may be necessary on a site-specific ...
 
...on a site-specific basis to evaluate the effects of tidal pumping on subslab soil vapor concentrations at high-risk, coastal sites with significant free product on shallow groundwater. ...
 
... At sites near the coast, the tides can affect groundwater levels, soil vapor samples should be collected at the same point in the tidal cycle in order to obtain data ...
 
...water tables) may also be necessarily, especially if significant concentrations of vapor-phase contaminants have been identified in deeper, soil vapor samples. A single ...
 
...contaminants have been identified in deeper, soil vapor samples. A single round of soil vapor sample collection will generally be acceptable ...
 
...samples. A single round of soil vapor sample collection will generally be acceptable for sites that meet the following conditions ...
 
...source is present in the vadose zone. At least two rounds of soil vapor sampling, one during the �dry� season and one during the �wet� season, are recommended prior ...
 
...season and one during the �wet� season, are recommended prior to negation of potential vapor intrusion hazards for sites that meet the following conditions: 1) Sites with widespread, ...
 
...above-noted conditions or 2) Confirmation of remedial actions at sites where potential vapor intrusion hazards have been documented in the past (e.g., concentrations of VOCs in ...
 
...hazards have been documented in the past (e.g., concentrations of VOCs in subslab soil vapor greater than action levels and/or impacts to indoor air above action levels or expected background ...
 
...impacts to indoor air above action levels or expected background identified and tied to vapor intrusion). If more than one round of soil vapor samples are collected, the field ...
 
...intrusion). If more than one round of soil vapor samples are collected, the field procedures (e.g., purge volume), sample containers, and analytical ...
 
... Short-term (minutes or days), temporal variation of concentrations in soil vapors due to changes in temperature, barometric pressure, and wind speed due to passing ...
 
...or more (USEPA 2007e). Infiltration from rainfall can potentially impact soil vapor concentrations by displacing soil vapor, dissolving volatile organic compounds, and by creating ...
 
...concentrations by displacing soil vapor, dissolving volatile organic compounds, and by creating a �cap� above the soil vapor. In practice, ...
 
...dissolving volatile organic compounds, and by creating a �cap� above the soil vapor. In practice, infiltration from brief, large storms only penetrates into the soil on the order ...
 
... from brief, large storms only penetrates into the soil on the order of inches. Soil vapor samples collected at depths greater than 3 feet bgs are therefore unlikely to be significantly ...
 
...depths greater than 3 feet bgs are therefore unlikely to be significantly affected. Soil vapor samples collected closer to the surface (less than 3 feet) without surface cover may be affected. ...
 
... a sample or drops of moisture are evident in the sampling train or sample, a soil vapor sample should not be collected (e.g., vacuum greater than seven inches Hg or 100 inches of ...
 
...short circuiting to the surface, imposition of a high vacuum on the soil could cause non vapor-phase VOCs to be stripped in free product, sorbed to soil or dissolved in soil moisture and ...
 
...in free product, sorbed to soil or dissolved in soil moisture and bias the resulting vapor sample. Measurement of soil moisture can also be useful if shallow sampling is performed during ...
 
...rainfall (e.g., greater than 1 inch; SDC 2011 7.10.2 Soil Vapor Probe Equilibration Subsurface soil vapor conditions are disturbed during installation ...
 
...Probe Equilibration Subsurface soil vapor conditions are disturbed during installation of soil vapor sampling probes. In general, temporary ...
 
...conditions are disturbed during installation of soil vapor sampling probes. In general, temporary probes advanced with manual or direct push ...
 
...advanced with manual or direct push methods result in the least disturbance to soil vapor conditions and can be purged and sampled relatively soon after installation. Permanent probes ...
 
...on the investigation objectives and the data quality requirements. For example, if a soil vapor survey is conducted using temporary points to map the extent of a vapor plume, and the ...
 
...survey is conducted using temporary points to map the extent of a vapor plume, and the sample data are not intended for use in risk assessment or site closure decisions, ...
 
...would be acceptable. To obtain quality data for decision making, permanent soil vapor probes should be allowed to equilibrate for at least 24 (direct push) to 48 (augers) hours ...
 
...test, leak test and soil gas sampling for at least two hours following completion of vapor probe installation; For soil gas wells installed with hollow stem or hand auger ...
 
...test, leak test and soil gas sampling for at least 48 hours following completion of vapor probe installation. For subslab soil gas probes installed in soil beneath ...
 
...test, leak test and soil gas sampling for at least two hours following completion of vapor probe installation For vapor collection pins installed directly into the slab, ...
 
...probe installation For vapor collection pins installed directly into the slab, do not conduct the purge volume test, ...
 
...leak test and soil gas sampling for at least twenty minutes following completion of vapor probe installation (e.g., see Cox-Colvin 2013); Cap the vapor pins ...
 
...probe installation (e.g., see Cox-Colvin 2013); Cap the vapor pins immediately after they are installed in order to minimize the potential for cross slab ...
 
...(e.g., air conditioned buildings under positive pressure). 7.10.3 Soil Vapor Probe Purging Vapor probes should be purged of stagnant or ambient air in tubing ...
 
...Probe Purging Vapor probes should be purged of stagnant or ambient air in tubing and other equipment and filled ...
 
...be purged of stagnant or ambient air in tubing and other equipment and filled with soil vapor prior to collection of a sample. The volume of air space in sand packs installed with the vapor ...
 
...prior to collection of a sample. The volume of air space in sand packs installed with the vapor point should be included in purging if less than 24 hours has lapsed since installation of ...
 
... for common borehole and tubing sizes. Opinions vary on the optimum volume of vapor to be purged from a vapor point prior to the collection of a sample. Several published studies ...
 
...to be purged from a vapor point prior to the collection of a sample. Several published studies for relatively coarse ...
 
...be in equilibrium with the surrounding native soils. The volume purged between different vapor points set at similar depths at a site should be approximately the same. ...
 
...depths at a site should be approximately the same. For in-slab, pin-type vapor points (e.g., Vapor PinsTM), minimal purging is required due to the small volume of air associated ...
 
...points (e.g., Vapor PinsTM), minimal purging is required due to the small volume of air associated with the pin ...
 
...a well point can have several drawbacks (SDC 2011). The larger the quantity of soil vapor drawn, the greater the uncertainty in the location of the collected sample. Large purge volumes ...
 
...five minute draw time for a one-liter canister. When purging a well point or collecting a vapor sample with a syringe, the flow rate is maintained by drawing the plunger back at a steady ...
 
... can result in a biased sample. Imposition of a high vacuum on the soil could cause non vapor-phase VOCs in free product, sorbed to soil or dissolved in soil moisture to be stripped and ...
 
...sorbed to soil or dissolved in soil moisture to be stripped and bias the resulting vapor sample. As flow rates and vacuum levels increase, the risk of leakage in the sampling probes ...
 
...problems for the laboratory, but also compromises the integrity of the sample data since vapor-phase compounds could partition into the water during storage and shipment of the sample. If ...
 
...Summa canister measures the vacuum in the canister, not the vacuum applied to the soil vapor probe. A qualitative method to quickly determine if the permeability of the soil ...
 
...reduction in the flow rate does not reduce the sampling vacuum, then an alternative vapor point would be installed with a large sand pack emplaced in the zone of interest (SDC 2011). ...
 
...three liters, which implies the use of approximately ten liters of sand for the pack. A vapor point is installed in the pack and completed at the surface. The top of the sand pack should ...
 
...be capped with bentonite to prevent break though to ambient air. A vapor sample should only be collected after the sand pack has reached equilibrium with the surrounding, ...
 
...in the sand pack. Sample size should be limited to one liter. The vacuum within the vapor probe should be measured during sampling to ensure that seven inches Hg is not exceeded during ...
 
...Hg is not exceeded during the purging and sample collection 7.10.4 Soil Vapor Sampling Trains A variety of sampling systems can be used to collect representative ...
 
... A variety of sampling systems can be used to collect representative soil vapor samples. Individual laboratories typically provide guidance on recommended designs of sampling ...
 
...be filled using a lung box. A lung box is an air-tight container with ports for the soil vapor probe tubing and separate tubing to a pump. The Tedlar bag is connected to the vapor probe ...
 
...probe tubing and separate tubing to a pump. The Tedlar bag is connected to the vapor probe tubing and then placed inside the lung box. A pump is used to evacuate the lung box, ...
 
...is used to evacuate the lung box, which causes the Tedlar bag to expand, drawing in soil vapor (Figure 7-33). A schematic diagram and photograph of a soil vapor sampling apparatus ...
 
...(Figure 7-33). A schematic diagram and photograph of a soil vapor sampling apparatus for collecting samples in Summa canisters is depicted in Figure 7-34 ...
 
...Summa canisters is depicted in Figure 7-34 and includes the following major elements: the vapor probe tubing, a vacuum gauge, sample tubing (inert tubing such as Teflon, nylon, or stainless-steel), ...
 
... Figure 7-35 shows several typical sampling apparatus in which soil vapor samples are being collected with a sorbent tube and Summa canisters. In the bottom, ...
 
...of the sampling train (see Section 7.10.5.1). 7.10.5 Soil Vapor Probe Leak Testing Leak tests are an important part of quality assurance and are ...
 
...tests are an important part of quality assurance and are strongly recommended for each vapor sample. The nature of leaks tests carried out as part of a site investigation should be clearly ...
 
...and discussed in the resulting report. Leaks in sampling train fittings or leaks at the vapor point annulus can result in dilution of the soil vapor samples with ambient air and under reporting ...
 
...point annulus can result in dilution of the soil vapor samples with ambient air and under reporting of actual contaminant concentrations. Most leaks ...
 
... Most leaks occur in the sampling train, rather than in the annulus around the vapor probe surface seal. Excessive vacuum conditions resulting from low porosity soils ...
 
...train in the field, 2) A �water dam� test for field testing of the integrity of the vapor point when installed into a slab or other relatively impermeable surface and 3) A tracer test ...
 
...and 3) A tracer test to determine the presence or absence of gas introduced around the vapor point and/or the sampling train in the sample that is collected. Performance of a shut-in test ...
 
...a shut-in test of the sampling train is recommended prior to the collection of all soil vapor samples. As described below, this allows the tightness of the sampling train to be quickly ...
 
...in the field. A water dam test, as described below, or equivalent test is recommended for vapor points installed in intact slabs prior to sample collection. This allows the tightness of the ...
 
...prior to sample collection. This allows the tightness of the annular space around the vapor point to be quickly tested in the field. Tracer tests are recommended to test the ...
 
...tested in the field. Tracer tests are recommended to test the tightness of vapor points installed in soil, cracked slabs, pavement or other cases where a bentonite seal is ...
 
...high public profile sites where where lab data are desired to confirm sampling chain and vapor point tightness. As described below, two tracer gas methods are recommended: (1) Application ...
 
...two tracer gas methods are recommended: (1) Application of a leak check compound to the vapor probe surface seal or (2) Application a tracer gas to the entire sampling apparatus. Table ...
 
...gas. Use of one of the two tracer methods described above is recommended for vapor points with connections that cannot be included in a shut-in test and for all samples collected ...
 
...initial sample drawn from the well point can be used to help verify the integrity of the vapor point prior to submittal of samples to a laboratory (e.g., collection of an initial sample ...
 
... A simple shut-in test will be adequate for the routine collection of soil vapor samples when the depth of the probe is greater than 10 feet and all connections in ...
 
... in the sampling train can be included in the test. Testing the tightness of the vapor point connection with the ground surface is less critical in these cases given the depth to ...
 
... of remaining samples. The use of a full shroud over both the sampling train and vapor point could, however, be recommended or even required for sites with a high public profile, ...
 
... Note that simple release of tracer gas around sampling train connections and the vapor probe seal at the ground surface in the absence of a shroud is not recommended, since the concentration ...
 
...types of helium field detectors due to very high concentrations of C5-C12 hydrocarbons in vapors in soil gas. This can be assessed prior to purging and sample collection by connecting ...
 
...prior to purging and sample collection by connecting the helium detector directly to the vapor point and evaluating the response. Ultra high-purity helium (e.g., Grade 5) is recommended ...
 
...in cheaper, �party-grade� helium High levels of light-end, petroleum vapors have also been reported to cause false, elevated readings of methane in vapor samples using ...
 
...have also been reported to cause false, elevated readings of methane in vapor samples using a standard, landfill gas analyzer. The use of a carbon trap is recommended when ...
 
... A sampling train shut-in test is recommended prior to the collection of all soil vapor samples. The shut-in test is performed by isolating the sampling train from the vapor sampling ...
 
...samples. The shut-in test is performed by isolating the sampling train from the vapor sampling point and applying a vacuum to the sampling train. The applied vacuum should hold ...
 
...trains arranged for a shut-in test. The system consists of a gas tight 2-way valve at the vapor probe termination, a 3-way valve to connect the vapor probe to the sample container, ...
 
... probe termination, a 3-way valve to connect the vapor probe to the sample container, and a vacuum gauge and syringe with shut-off valve. The 2-way ...
 
... should be rechecked and the shut-in test repeated. 7.10.5.2 Water Dam Vapor Point Test A �water dam� offers a simple and inexpensive method to test for leaks ...
 
... A �water dam� offers a simple and inexpensive method to test for leaks around vapor points installed into a slab or other relatively impermeable surface (e.g., see Cox-Colvin ...
 
...installation, water is poured directly into the depression cut into the floor around the vapor point (see Figure 7-30). For a stick-up installation, a coupling can be sealed to ...
 
...or the annular space of a flush-mount depression to immerse the tubing connection to the vapor point. Note that water soluble clays such as Play-Doh might absorb too much water to be ...
 
...for tests that last more than one hour. Assemble the sample train and connect it to the vapor point. Perform a shut-in test to verify that the sample train can hold a vacuum for one to ...
 
...five minutes with no more than 0.5 in Hg loss of vacuum (see previous section). Purge the vapor point and monitor the water level in the dam. The water level might drop slightly due to absorption ...
 
... however. If this occurs then remove the distilled water and reposition or reseal the vapor point to address the leak. 7.10.5.3 Tracer Method 1 � Application of Tracer ...
 
...apparatus (Method 2), including sample container, all tubing and connections, and the vapor probe surface completion in a shroud, which is filled with tracer gas. ...
 
...shroud is the ability to document the lack of a leak in both the sampling train and the vapor point seal by testing for helium in the sample analyzed by the laboratory. Combination with ...
 
...collected and analyzed then it can also be concluded that the leak occurred around the vapor point annular seal. A disadvantage of full-system shrouds is the volume of helium required, ...
 
...concentrations of VOCs are within ten percent of the actual concentration of VOCs at the vapor point in the field at the time the sample was collected. If a field meter is not used to monitor ...
 
...leak. Fully document and discuss any detections of leak check compound in the soil vapor investigation report. 7.10.5.6 Selection of Leak Check Compound ...
 
...does not require the use of a shroud, as it can be applied to a towel placed around the vapor probe, although it can also be used with a shroud by placing the towel inside the shroud. Isopropanol ...
 
...and may be particularly useful for testing leaks associated with the anular space of the vapor point (see Figure 7-43). A further advantage of isopropanol is that it can be detected using ...
 
...Quantification of leaks is likewise difficult, since the original concentration of vapor-phase isopropanol under the shroud can at best be estimated based on its vapor pressure. Isopropanol ...
 
...isopropanol under the shroud can at best be estimated based on its vapor pressure. Isopropanol is also sometimes used as an additive in gasoline. This could again lead ...
 
... adequate mixing under a shroud if it is used as a tracer for leak detection around vapor points. Difluoroethane (in office duster cans) is readily available and simpler ...
 
...a comparison of these leak check compounds. 7.10.6 Soil Vapor Sample Collection Steps The following general steps should be followed when collecting ...
 
...Steps The following general steps should be followed when collecting soil vapor samples: Allow the sampling probe to equilibrate with the subsurface ...
 
... Purge the sampling apparatus as discussed in 7.10.3. Collect the soil vapor sample into the appropriate sample container. Disassemble the sampling apparatus ...
 
...apparatus making sure to close the valves on the sample container and the soil vapor sampling probe. Transport the sample to the analytical laboratory ...
 
... following standard chain-of-custody procedures. 7.10.7 Soil Vapor Sample Notes and Logs Good field notes and logs are important components of soil ...
 
...Notes and Logs Good field notes and logs are important components of soil vapor investigations. Take clear notes in the field. State the goals of each planned activity at ...
 
...and devices; Purging and sampling rates; PID readings; Soil vapor probe system volumes; Volume of soil vapor extracted prior to sampling; ...
 
...probe system volumes; Volume of soil vapor extracted prior to sampling; Sample volume; If canisters are used, vacuum ...
 

9.1 Pesticide Contamination at Former Agricultural Facilities and Sites
... 2012b). An evaluation of potential contaminant mobility in terms of vapor-phase or dissolved-phase (i.e., leachate) mobility in soil is important (refer to Appendix ...
 
...as "volatile" in the HDOH EHE guidance are considered to be highly mobile in the vapor phase [Henry's number >0.00001 atmosphere cubic meters per mole (m3/mol)] and molecular ...
 
...be a contaminant of concern in former pesticide mixing, storage or disposal areas. Soil vapor data collection is strongly recommended when investigating for these areas. ...
 
...(chronic direct exposure), Ametryn and atrazine (leaching), Petroleum (vapor intrusion, gross contamination, leaching), Lead (chronic direct exposure), ...
 

9.3 Petroleum Contaminated Sites
...ranges. As discussed below, reference to these ranges is less useful for air and soil vapor data. "Gasoline-range" TPH is defined as a mixture of petroleum compounds characterized ...
 
...alkenes, and cycloalkanes of the same carbon range (see also NEIWPCC 2003). Vapors from these fuels tend to be dominated by lighter-range, more volatile, C5-C8 aliphatics (HDOH, ...
 
...These fuels also contain a small but important amount of lighter, aliphatic compounds. Vapors from the fuels can somewhat counterintuitively be dominated by these "gasoline range," C5-C12, ...
 
...it is important that these compounds be included in the analysis of TPH in air and soil vapor samples associated with releases of middle distillate fuels. Dissolved-phase, middle-distillate ...
 
...petroleum compounds (Chaplin 2002). This necessitates the collection of soil vapor samples at sites contaminated by heavier fuels, as well as gasolines and middle distillates. ...
 
...etc.) Soil Vapor TPH, BTEX, naphthalene and MTBE plus other ...
 
...and 2-) Soil Vapor TPH, BTEX, naphthalene, and methane ...
 
... Soil Vapor TPH, VOCs, naphthalene, and methane ...
 
... 1.    Include any additional volatile additives in soil vapor samples if suspected to be present. 2.    VOCs ...
 
... provided in Table 9-5. Petroleum contamination in soil, water or air/soil vapors should be evaluated in terms of both TPH and a short list of target "indicator chemicals" ...
 
...specific PAHs. Methylnaphthalenes do not need to be reported for soil vapor samples as a default. Based on data reviewed by HDOH, these compounds are unlikely to drive ...
 
... Based on data reviewed by HDOH, these compounds are unlikely to drive potential vapor intrusion hazards at petroleum release sites over TPH or benzene due to their relatively low ...
 
...in most middle distillates and residual fuels. Testing for these compounds in soil vapor also requires different sample collection and analytical methods (e.g., sorbent tubes and TO-1 ...
 
...sorbent tubes and TO-1 analysis; see Section 7.8.2). Reporting of these compounds in soil vapor samples may, however, be required at sites impacted by Manufactured Gas Plant waste. ...
 
... 9.3.1.2 Total Petroleum Hydrocarbons Soil, groundwater, and soil vapor samples must always be tested for TPH (or equivalent) in addition to targeted, individual ...
 
...material in the soil. The concentration of TPH (or equivalent) in soil vapor should always be reported as the sum of C5-C12 compounds for whole air samples and C5-C18 for ...
 
...Brewer et al 2013). As discussed above and in Section 7.8.2, results from a petroleum vapor study carried out by HDOH study indicate that C5-C8 aliphatic compounds can make up ...
 
...compounds can make up a significant if not dominant fraction of the total TPH present in vapors associated with diesel and other middle distillate fuels (HDOH, 2012, 2012c). This ...
 
...of C5-C8 aliphatics to the total concentration of TPH reported in air or soil vapor samples associated with middle distillate fuels would be inappropriate, however. ...
 
...this issue, laboratories should be instructed to report TPH (or equivalent) in air or vapor samples as: 1) The sum of C5-C12 compounds for whole-air samples (e.g., summa canister samples ...
 
...data indicate that C12+ compounds make up less than 10% of the total TPH present in vapors. Designation of chromatogram patterns as "gasoline range" (e.g., C5-C12) or "diesel ...
 
...to traditional, laboratory methods for TPH in soil or water is not applicable to air and vapor samples and can be misleading. The reported concentration of TPH can then be compared to HDOH ...
 
... of both Summa canister samples and sorbent tube samples is recommended for soil vapor investigations at diesel and middle distillate sites. This is due to limitations on the ability ...
 
...both TPH and target, indicator compounds such as BTEX and naphthalene). A maximum, 50ml vapor draw might be required for sorbent tube samples due to limitations of the sorbent material ...
 
...canisters can be relied upon for the collection of future samples. If >10% of the vapor-phase TPH is associated with >C12 compounds then a combined use of Summa data and sorbent ...
 
...however, these compounds make up an insignificant (i.e., <10%) proportion of TPH vapors at typical, petroleum-release site. Reported concentrations of unidentified hydrocarbons ...
 

10.6 Field QA/QC
...is typically analyzed for volatile organic compounds in aqueous samples due to the high vapor pressure and potential for vapor migration. Non-aqueous samples collected using methanol preservation ...
 
...pressure and potential for vapor migration. Non-aqueous samples collected using methanol preservation techniques may also require ...
 

11.0 HANDLING AND ANALYSIS OF SAMPLES
...phase samples is not included in this section; guidance on handling and analysis of soil vapor or indoor air samples is presented in Section 7. Quality assurance/quality control ...
 

11.2 SAMPLE PRESERVATION AND HOLD TIMES
...include: sampling gravely soil matrix (if using EnCore® type samplers), spillage or evaporation of pre-weighed chemical preservatives, shipping restrictions involving chemical ...
 

Contents
... 13.2 DEVELOPMENT OF VAPOR INTRUSION SCREENING TOOLS   ...
 
...   13.2.2 VAPOR ATTENUATION IN TROPICAL VERSUS COLD CLIMATES   ...
 

13.0 Environmental Hazard Evaluation
...of the most pressing hazards (e.g., discharges of free product into storm sewers, vapor intrusion into overlying buildings) and other site-specific considerations. Contamination ...
 

13.1 TARGET ENVIRONMENTAL HAZARDS
... - Vapor Intrusion ...
 
...in soil via incidental ingestion, dermal absorption and inhalation of vapors or dust in outdoor air. ...
 
... - Vapor Intrusion ...
 
... Vapor Emissions ...
 
... odor and nuisance concerns and in some cases even result in explosive levels of vapors in soil gas. Although it may seem counterintuitive, it is quite possible for soil that is ...
 
...by direct exposure hazards (e.g., arsenic, lead, polychlorinated biphenyls [PCBs]). Vapor intrusion typically drives environmental hazard for soil contaminated with volatile carcinogens, ...
 
...water toxicity hazards are almost always identified for contaminated aquifers. Potential vapor intrusion hazards will also usually be identified for groundwater contaminated with carcinogenic, ...
 
...offsite and discharge into a surface water body. Free product also poses potential vapor intrusion hazards for nearby buildings as well as potential explosive, subsurface vapor hazards. ...
 
...intrusion hazards for nearby buildings as well as potential explosive, subsurface vapor hazards. Other potential environmental hazards may require attention at some sites, ...
 

13.2 DEVELOPMENT OF VAPOR INTRUSION SCREENING TOOLS
... ' 13.2 DEVELOPMENT OF VAPOR INTRUSION SCREENING TOOLS The collection of soil vapor samples as part of a site ...
 
...INTRUSION SCREENING TOOLS The collection of soil vapor samples as part of a site characterization and vapor intrusion investigation is discussed in ...
 
...samples as part of a site characterization and vapor intrusion investigation is discussed in Section 7. The technical background and development ...
 
...investigation is discussed in Section 7. The technical background and development of soil vapor and indoor air action levels for assessment of potential vapor intrusion hazards is presented ...
 
...and indoor air action levels for assessment of potential vapor intrusion hazards is presented in the HDOH Environmental Hazard Evaluation (EHE) guidance (HDOH, ...
 
... guidance also presents soil and groundwater action levels for screening of potential vapor intrusion hazards. The collection of soil vapor data is recommended for all sites where potentially ...
 
...intrusion hazards. The collection of soil vapor data is recommended for all sites where potentially significant releases of volatile chemicals ...
 
...occurred. A key factor in development of the action levels for potential vapor intrusion risks is the assumed attenuation of subsurface vapors as they intrude a building ...
 
...intrusion risks is the assumed attenuation of subsurface vapors as they intrude a building and mix with indoor air. Assumptions incorporated into the vapor ...
 
...as they intrude a building and mix with indoor air. Assumptions incorporated into the vapor intrusion models are discussed in Sections 2 and 3 of Appendix 1 of the EHE guidance and based ...
 
...et al., 2014b.). The research represents an important update to indoor air:subslab soil vapor attenuation factors initially proposed by USEPA researchers in the early 2000s and published ...
 
...database relied on a single, small-volume (e.g., one-liter), randomly located, subslab vapor sample to represent intruding vapors (attenuation = indoor air sample concentration/subslab ...
 
...sample to represent intruding vapors (attenuation = indoor air sample concentration/subslab vapor sample concentration). Attenuation ...
 
...(attenuation = indoor air sample concentration/subslab vapor sample concentration). Attenuation factors derived from the database were an order of magnitude ...
 
...sites with relatively minimal VOC contamination to be unnecessarily flagged for potential vapor intrusion risks. Reliability of the approach used by USEPA required a high degree ...
 
...the approach used by USEPA required a high degree of uniformity of VOC concentrations in vapors beneath building slabs. Collection of a vapor sample from another location under the building ...
 
...beneath building slabs. Collection of a vapor sample from another location under the building slab would otherwise generate a different ...
 
...attenuation factor estimated was random and unlikely to be representative of actual vapor intrusion conditions. As discussed by Brewer et al. (Brewer et al., 2014b.), subslab ...
 
...conditions. As discussed by Brewer et al. (Brewer et al., 2014b.), subslab vapor plumes are in fact likely to highly heterogenous. This, in addition to uncertainty regarding ...
 
...in fact likely to highly heterogenous. This, in addition to uncertainty regarding actual vapor entry points into a building, negates the validity of the USEPA database for derivation of ...
 
...regions where buildings are not heated throughout the year were used to develop soil vapor action levels presented in the HDOH EHE guidance. Two USEPA vapor intrusion guidance ...
 
...action levels presented in the HDOH EHE guidance. Two USEPA vapor intrusion guidance documents were being finalized for publication at the time that the Brewer ...
 
...the time that the Brewer at al. (Brewer at al., 2014b.) research was published, one for vapor intrusion in general (USEPA 2015c.) and one specific to vapor intrusion associated with ...
 
...intrusion in general (USEPA 2015c.) and one specific to vapor intrusion associated with petroleum (USEPA 2015b). The research published by Brewer ...
 
...by Brewer et al. (Brewer et al., 2014b.) is referenced in the USEPA petroleum vapor intrusion guidance. The research is not, however, referenced in the general vapor guidance. ...
 
...intrusion guidance. The research is not, however, referenced in the general vapor guidance. This was due to completion of the final review of the guidance document prior to ...
 
...vetting concluded for the (2015) OSWER Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air (OSWER Publication 9200.2-154). ...
 
...Intrusion Pathway from Subsurface Vapor Sources to Indoor Air (OSWER Publication 9200.2-154). By contrast, the (2015) Technical ...
 
...Publication 9200.2-154). By contrast, the (2015) Technical Guide for Addressing Petroleum Vapor Intrusion at Leaking Underground Storage Tank Sites (EPA 510-R-15-001) was prepared and revised ...
 
...and revised somewhat independently. Although publication of the USEPA vapor intrusion guidance documents postdate publication of the Brewer et al. (Brewer et al., 2014b.) ...
 
...of the Brewer et al. (Brewer et al., 2014b.) research, presentation of indoor air:subslab vapor attenuation factors in the documents based on the 2012, USEPA �empirical database� should be ...
 
...database� should be considered invalid and not referred to for use in site-specific, vapor intrusion investigations. ...
 

13.3 TIER 1 ENVIRONMENTAL ACTION LEVELS
... as assumed in the default, Tier 1 CSMs and EALs. Soil action levels for direct exposure, vapor intrusion and gross contamination hazards are higher (i.e., less stringent) than correlative ...
 
...because land use does not alter the threat to groundwater. Groundwater action levels for vapor intrusion hazards are also higher for a commercial/industrial land use scenario. Action levels ...
 
...13-5c), the input concentration of benzene in soil (5.1 mg/kg) causes direct exposure, vapor intrusion and leaching hazards to be flagged. Potential impacts to terrestrial ecological receptors ...
 
...concentration of volatile contaminants in soil or groundwater exceed action levels for vapor intrusion concerns, then soil gas data can be collected to more closely evaluate this potential ...
 
...soil gas data is very useful (and strongly recommended) for more detailed evaluations of vapor intrusion concerns. The inclusion of soil gas action levels in this guidance helps expedite ...
 
...some cases (e.g., direct exposure to non-volatile contaminants) and not in others (e.g., vapor intrusion or leaching hazards). Using the detailed action levels to understand the ...
 
...used as a source of drinking water is obviously important. Expeditious actions to address vapor intrusion hazards posed by contaminated soil are usually warranted. In contrast, long-term ...
 

13.4 CHEMICALS NOT LISTED IN LOOKUP TABLES
... hazards posed by contaminated soil. In particular, the RSLs do not address potential vapor intrusion, leaching or gross contamination hazards and may not adequately address cumulative ...
 

13.5 STEPS TO ENVIRONMENTAL HAZARD EVALUATION
...petroleum-related contamination in particular, soil gas data often indicate a much lower vapor intrusion hazard than predicted by simple comparison of soil or groundwater data to HEER Office ...
 
... Vapor Intrusion ...
 
...and subsequent evaluation of risk to human health (site-specific vapor intrusion model) ...
 
... Vapor Intrusion ...
 
...and subsequent evaluation of risk to human health risk (site-specific vapor intrusion model) ...
 
...contamination of groundwater. Soil or groundwater data flagged for potential vapor intrusion almost always indicates that soil gas samples should be collected at the site. The ...
 
...at the site. The model used to develop the soil and groundwater actions levels for vapor intrusion hazards estimates the concentration of a volatile contaminant in shallow soil gas ...
 
...issues to consider include: 1) What areas of the site pose potential direct exposure or vapor intrusion hazards? 2) What areas of the site pose potential leaching hazards? and 3) In what ...
 
... leaching hazard. In a third area, soil contaminated with chlorinated solvents poses vapor intrusion hazard, a direct exposure hazard and a leaching hazard. In a fourth area, soil contaminated ...
 
...mobile contaminants often pose a combination of several environmental hazards, including vapor intrusion, direct exposure and leaching (e.g., PCE). The environmental ...
 
...short time frame will, in contrast, require some type of impermeable cap. Subslab vapor mitigation systems will be required for new buildings placed within the vapor intrusion hazard ...
 
...mitigation systems will be required for new buildings placed within the vapor intrusion hazard area. Indoor air studies may be needed for existing buildings located in this ...
 
...environmental hazard(s) posed in a given area of the site including capping, vapor mitigation systems, offsite disposal, etc. (see text). ...
 
...levels for the noted hazard. Aggressive remediation should focus on removal of vapor intrusion hazard so property can be redeveloped. Aggressive remediation of groundwater ...
 
...evaluated. This could include restrictions on future use of the property, installation of vapor mitigation systems under buildings, capping of contaminated soil to prevent exposure or leaching, ...
 

13.6 PREPARATION OF ENVIRONMENTAL HAZARD EVALUATION REPORTS
...of contaminants in soil ("direct exposure"), impacts to water supply wells, intrusion of vapors or methane into overlying structures (including explosive hazards) and discharges of free ...
 

15.6 Site Cleanup Process
...remediate contamination that is causing immediate environmental hazards (e.g. vapor intrusion into a building) and prepare an Environmental Hazard Management Plan (EHMP) to address ...
 

16.2 Setting Remedial Action Objectives and Conducting a Remedial Alternatives Analysis
... contaminant in a smaller volume. Examples include: Soil vapor extraction to extract volatile contaminants from subsurface soils ...
 
...soil with a concrete cap On-site containment of soil gas with vapor barriers or active ventilation systems On-site containment of contaminated ...
 

18.5 Document Outlines
...   5.4 Soil Vapor Investigation   ...
 
...   5.5 Soil Vapor Sampling Activities   ...
 
...significant, environmental concerns remain but active remediation (e.g., excavation, soil vapor extraction, etc.) is no longer practical. This type of letter is often used when further excavation ...
 

19.0 Site Closures
...significant environmental concerns remain, but active remediation (e.g., excavation, soil vapor extraction, etc.) is no longer practical. This status may be helpful to site owners, financial ...
 

19.1 Site Closure Scoping
...operation and maintenance of an active engineering control, such as an active vapor mitigation system. Failing to implement, maintain, and report on required monitoring. ...
 
...exposure, such as constructing a new building on the site without the necessary vapor mitigation measures. Sale of the property without appropriate disclosures ...
 

19.3 Closures with Use Restrictions
... and resulting data may indicate a potential environmental hazard from subsurface vapor intrusion into indoor air spaces. The site may be closed with restricted use, but engineering ...
 
...The site may be closed with restricted use, but engineering controls (e.g., an active vapor mitigation system); institutional controls (i.e., an environmental covenant to restrict land ...
 

19.4 No Further Active Remediation Letter
...significant, environmental concerns remain but active remediation (e.g., excavation, soil vapor extraction, etc.) is no longer practical. This type of letter is often used when further excavation ...
 

19.6 Environmental Hazard Management Plan
...included. This could include restrictions on future use of the property, installation of vapor mitigation systems under buildings, capping of contaminated soil to prevent exposure or leaching, ...
 

19.7 Institutional and engineering Controls
... which are methods of exposure prevention by physical means (for example, an active vapor mitigation system to prevent subsurface vapor intrusion into indoor air spaces). ...
 
...mitigation system to prevent subsurface vapor intrusion into indoor air spaces). Institutional controls alone are generally not ...
 
...an engineering control of contaminated sediments, as well. Soil Vapor Contamination Vapor barriers � impermeable materials are placed beneath a proposed ...
 
...Contamination Vapor barriers � impermeable materials are placed beneath a proposed building site to prevent ...
 
...materials are placed beneath a proposed building site to prevent subsurface vapor intrusion into indoor air spaces. Active vapor removal systems should be considered for ...
 
...intrusion into indoor air spaces. Active vapor removal systems should be considered for sites with significant soil gas issues in which ...
 
...a suction fan, which may be vented above the roof of the building, or connected to a vapor treatment system such as a thermal oxidizer or granular activated carbon. ...
 

Log of TGM Updates
... 7 Soil Vapor and Indoor Air Sampling Guidance Dec 2017 ...
 
...report Field Investigation of the Chemistry and Toxicity of TPH in Petroleum Vapors. Reference: HDOH 2012c Oct 2012 ...
 

PDF Download Page
... Section 7 - Soil Vapor and Indoor Air Sampling Guidance ...
 
... Field Investigation of the Chemistry and Toxicity of TPH in Petroleum Vapors: Implications for Potential Vapor Intrusion Hazards. ...
 
...Implications for Potential Vapor Intrusion Hazards.   ...
 

Additional Guidance Documents" Language="VB" MasterPageFile="~/lib/Content.master
...Field Investigation of the Chemistry and Toxicity of TPH in Petroleum Vapors This Q&A provides responses to common questions ...
 
...responses to common questions regarding the August 2012 HDOH TPH vapor report. Reference: HDOH 2012c ...
 
...evaluation of environmental hazards, including direct exposure, vapor intrusion, leaching and contamination of groundwater, impacts to drinking ...
 

7.10 Documentation of Soil Vapor or Indoor Air Sampling
...Guide (MADEP 2002b); DoD: Tri-Services Handbook for the Assessment of the Vapor Intrusion Pathway (DoD 2008); Massachusetts: Vapor Intrusion Guidance ...
 
...Intrusion Pathway (DoD 2008); Massachusetts: Vapor Intrusion Guidance (MADEP 2010); and California: Guidance for the Evaluation ...
 
...and California: Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air (CalEPA 2011). Due to potential complications ...
 
...indoor and outdoor sources of VOCs, the collection of indoor air samples as part of a vapor intrusion study will rarely be practical or recommended (see Sections 7.2 and 7.3). ...
 
...collection of indoor air samples is only recommended if concentrations in subslab soil vapor exceed 1,000 times (residential) to 2,000-times (commercial/industrial) anticipated background ...
 
...demonstrate a link between apparent impacts to indoor air and the intrusion of subsurface vapors (refer to Section 7.1 and HEER Office EHE guidance, HDOH, 2016). This includes the ...
 
...on shallow groundwater), concentrations of targeted VOCs in source area and subslab soil vapor samples, presence or absence of apparent pathways for vapor intrusion, building ventilation ...
 
... samples, presence or absence of apparent pathways for vapor intrusion, building ventilation design and operation (e.g., likelihood to be over- or under-pressured) ...
 
...or risk, it may be also useful to collect a sample(s) directly from a point of suspected vapor entry, including bathrooms, utility rooms or other areas where utilities protrude through the ...
 
...be evaluated and taken into consideration. For example, buildings may be more prone to vapor intrusion during periods of the year when air conditioning is not routinely used and ...
 
...due to wind effects is increased. Buildings could also be more susceptible to vapor intrusion during dry periods of the year due to the exposure of subsurface smear zones as the ...
 
...If collecting a combination of indoor air samples, outdoor air samples, and sub-slab soil vapor samples for one project, the indoor and outdoor air samples should be collected concurrently, ...
 
... collected concurrently, immediately followed by collection of the sub-slab soil vapor samples. The collection of sub-slab samples simultaneously with the indoor air samples it not ...
 
...ambient air samples should be collected when conducting indoor air sampling as part of a vapor intrusion study. Ambient air samples are important for evaluation of potential outdoor sources ...
 
...VOCs. Like indoor air, ambient air can contain a number of VOCs typically targeted for vapor intrusion studies. Examples include TPH, BTEX and other petroleum-related chemicals associated ...
 
...It is recommended that a checklist be used as a guide when conducting building surveys. Vapor intrusion assessment guidance manuals from the USEPA (USEPA 2004e), the Interstate Technology and Regulatory ...
 
...building survey checklists, as do several other state guidance documents (see also vapor intrusion discussion in HEER EHE guidance; HDOH, 2016). As part of the building ...
 
...guidance; HDOH, 2016). As part of the building survey, potential preferential vapor intrusion pathways should also be evaluated. Utility corridors can act as contaminant migration ...
 
...pathways allowing VOCs to travel long distances. Primary entry points for subsurface vapors include bathrooms, kitchens and utility rooms where water, sewer, gas, electric and ...
 
...lines penetrate the floor. Wall outlets for electrical fixtures can also serve as a vapor intrusion pathway. Depending on the COPC, screening for VOCs using direct reading ...
 
...the parts per billion (ppb) range, and are best used for screening at points of potential vapor entry, locating indoor VOC sources, or identifying acute exposure or potentially explosive ...
 
...or identifying acute exposure or potentially explosive situations. Note that petroleum vapors are dominated by aliphatic compounds. PIDs primarily target aromatic compounds and are not ...
 
... target aromatic compounds and are not good indicators of total TPH levels in soil vapors without inclusion of a correction factor (ASTM 2006f; refer also to HDOH, 2012). This is especially ...
 
... refer also to HDOH, 2012). This is especially important to remember for aromatic-poor vapors from diesel fuel of other middle distillate fuels. 7.11.2 Indoor ...
 
...within the building and any sensitive populations that may be exposed to the contaminated vapors. In structures with basements, both the occupied living areas and basement areas should be ...
 
...with the latter most commonly selected (see Section 7.13). For vapor intrusion studies, the suite of VOCs targeted for Indoor and outdoor air samples should be ...
 
...for Indoor and outdoor air samples should be identical to the suite targeted for soil vapor and identified in subslab soil vapor samples. Inclusion of additional VOCs can complicate the ...
 
...and identified in subslab soil vapor samples. Inclusion of additional VOCs can complicate the evaluation of impacts associated purely ...
 
...of additional VOCs can complicate the evaluation of impacts associated purely with vapor intrusion. 7.11.6 Indoor-Outdoor Air Sample Logs A sample ...
 

7.10 Documentation of Soil Vapor or Indoor Air Sampling
... ' 7.12 PASSIVE SOIL VAPOR AND INDOOR AIR SAMPLE COLLECTION PROCEDURES ...
 
... Figure 7-41: Installing a Passive Soil Vapor Sample Collector by Hand The hole is drilled using a roto-hammer. The soil vapor sample ...
 
...Sample Collector by Hand The hole is drilled using a roto-hammer. The soil vapor sample collector is installed using an insertion rod. The hole is then covered. ...
 
... Figure 7-42: Example Plume Map from Grid-based Passive Soil Vapor Survey. Passive sampling can be applied to either soil ...
 
... Passive sampling can be applied to either soil vapor or indoor air. Although the principle is the same in application to these media, the techniques ...
 
...retrieval and analysis are different. 7.12.1 Passive Sampling of Soil Vapor Implementing a passive soil vapor sampling strategy in the field requires careful ...
 
... Implementing a passive soil vapor sampling strategy in the field requires careful consideration of the pertinent sampling variables, ...
 
...locations for passive sampling is based upon the same considerations as active soil vapor methods: project objectives and the need for adequate coverage. Predetermined and widely spaced ...
 
... source as possible in order to reduce the chance of placing the sampler in a pocket of vapor-free soil in an otherwise contaminated area. In addition, collectors buried close to the surface ...
 
...of time. The key assumption that is made when interpreting passive soil vapor data is that each collector is exposed to the same quantity of soil vapor. Therefore, it is ...
 
...data is that each collector is exposed to the same quantity of soil vapor. Therefore, it is most important that passive collectors within a sampling program be deployed ...
 
... QA/QC: The most important factors affecting the quality of passive soil vapor data is consistency of deployment and potential contamination of the samplers. Sampling ...
 
...to the laboratory. There are several vendors of passive soil vapor sample collectors and those vendors should be consulted regarding specific installation procedures ...
 
... collector is shown in Figure 7-41. An example plume map from a grid-based passive soil vapor survey is shown in Figure 7-42. 7.12.2 Passive Sampling of ...
 

7.10 Documentation of Soil Vapor or Indoor Air Sampling
... ' 7.13 SOIL VAPOR AND INDOOR AIR SAMPLE ANALYSIS The analytical methods selected for analyzing soil ...
 
...INDOOR AIR SAMPLE ANALYSIS The analytical methods selected for analyzing soil vapor or indoor air samples depend on a number of factors. These include the targeted VOCs, desired ...
 
...and reporting limits and the manner in which the sample is collected. In Hawai`i, soil vapor or indoor air samples are in most cases forwarded to a fixed analytical laboratory ...
 
...(VOCs) A variety of analytical methods are available to measure soil vapor samples all of which give accurate results. Table 7-10 gives a summary of the available ...
 
...as the sum of C5 to C12 (Summa canister samples) and/or C5-C18 (sorbent tube samples) for vapors associated with all types of petroleum fuels, including diesel and other middle distillate ...
 
... of TPH compounds as �gasoline-range� or �diesel-range� is not applicable to soil vapors. As discussed in Section 7.13.1.2, vapors associated with diesel and other middle distillate ...
 
...As discussed in Section 7.13.1.2, vapors associated with diesel and other middle distillate fuels could, in theory, include ...
 
...and to a lesser degree aromatic compounds (see HDOH, 2012). Inclusion of heavier, vapor-phase compounds in the measurement of TPH will require the use of a sorbent method (e.g., ...
 
...VOCs and TPH (see Section 7.8.2). This will almost always be the case for soil vapors associated with petroleum. If initial sorbent data (or prior knowledge at a similar site) ...
 
...petroleum. If initial sorbent data (or prior knowledge at a similar site) indicates that vapors are dominated (e.g., >90%) by C5-C12 compounds then subsequent TPH data can be obtained ...
 
...for its selection, and analytical results should be fully documented in the final soil vapor or indoor air investigation report. ...
 
... Table 7-10 Summary of Soil Vapor & Indoor Air Analytical Methods1 ...
 
...can be reanalyzed as needed. TO-13 can be used to quantify heavier TPH in vapors but may not adequately capture light-end VOCs (consult the laboratory). ...
 
... Table 7-11 HDOH-Recommended Laboratory Analytical Methods for Soil Vapor or Indoor Air Contaminants and Leak Detection Compounds ...
 
...HDOH and laboratory staff, The best laboratory method to test for TPH in soil vapors appears to be a combination of both TO-15 (Summa canister samples) and TO-17 (sorbent ...
 
...in Section 9 and the HEER Office EHE guidance (HDOH, 2016 and updates), testing of vapors associated with petroleum should include a short list of target indicator compounds (e.g., ...
 
... Section 9, Table 9-5. Total Petroleum Hydrocarbons represents the sum of the vapor-phase, aliphatic and non-targeted, individual aromatic compounds. This is sometimes subdivided ...
 
...released. A distinction between TPHg and TPHd compounds is misleading for vapor-phase petroleum, however, since vapors from diesel and other middle distillate fuels or fuels ...
 
...petroleum, however, since vapors from diesel and other middle distillate fuels or fuels that include middle distillates (e.g., ...
 
...of lighter end compounds, especially C5-C8 aliphatics. Requesting the lab to report vapor-phase TPH as the equivalent of �TPHd� (i.e., sum of C10+ compounds) could significantly ...
 
...C10+ compounds) could significantly underestimate the actual concentration of TPH in soil vapors. This issue was investigated and discussed in the HEER Office study Field Investigation ...
 
...HEER Office study Field Investigation of the Chemistry and Toxicity of TPH in Petroleum Vapors: Implications for Potential Vapor Intrusion Hazards (HDOH, 2012, 2012c; Brewer ...
 
...Implications for Potential Vapor Intrusion Hazards (HDOH, 2012, 2012c; Brewer et al 2013). The study suggested ...
 
...et al 2013). The study suggested that the proportion of C5-C8 aliphatic compounds in vapors associated with middle distillate fuels is highly variable but can be up to 50% or more of ...
 
...fuels is highly variable but can be up to 50% or more of the total TPH. Excluding these vapors from the TPH analysis can significantly under-report the total TPH present in a vapor sample. ...
 
...from the TPH analysis can significantly under-report the total TPH present in a vapor sample. The study also indicated that individual, targeted aromatic compounds such as BTEX ...
 
... aromatic compounds such as BTEX typically make up less than 1% of the total petroleum vapors present. Vapor intrusion risk associated with the TPH fraction of petroleum vapors ...
 
...present. Vapor intrusion risk associated with the TPH fraction of petroleum vapors has only recently begun ...
 
...intrusion risk associated with the TPH fraction of petroleum vapors has only recently begun to be investigated in detail (e.g., Brewer et al 2013; ...
 
...to toxicity factors and action levels, the higher proportion of TPH aliphatics in the vapors causes these compounds to be the primary risk driver with respect to potential vapor intrusion ...
 
...causes these compounds to be the primary risk driver with respect to potential vapor intrusion concerns. Ongoing evaluations of soil gas field data will help address the lack of ...
 
...field data will help address the lack of published information on the relative risk of vapor intrusion (quantitatively considered) posed by TPH versus benzene and other individual compounds. ...
 
...highlights the potential problems associated with one-time sampling events and limited vapor points (see Section 7.10.1). For vapors associated with gasoline-only ...
 
... points (see Section 7.10.1). For vapors associated with gasoline-only releases, TPH (or equivalent) should be reported as the sum ...
 
...the carbon range from C5 to C12 (non-BTEX aromatics typically reported to C10). For vapors associated with middle distillate (and heavier) fuels, including diesel, TPH should be ...
 
...range� TPH in the sample, since doing so excludes reporting of C5-C9 aliphatics in soil vapors and could significantly underestimate the total concentration of TPH-related compounds. As ...
 
... TPH soil gas action levels; HDOH, 2016). The concurrent collection of soil vapor samples using both a Summa canister and a sorbent tube is recommended for the investigation ...
 
...a Summa canister and a sorbent tube is recommended for the investigation of subsurface vapors associated with diesel or other middle distillate fuels (see Section 7.8). This should ...
 
...fuels (see Section 7.8). This should be incorporated into both traditional, small-volume vapor sampling methods as well as LVP methods. The draw volume for sorbent tube samples is typically ...
 
...7.8.2). The Summa canister sample is likely to be more representative of subsurface vapors, given its larger volume. This sample should be collected first, following purging, ...
 
...soil. The sorbent tube sampling train should then be attached to the vapor point and a shut-in leak test performed. Following successful completion of a shut-in test, ...
 
...can be drawn that a significant proportion of C12+ compounds are not present in the soil vapors and Summa canister samples can be used for future sample collection. A review of the TO-17 ...
 
... for the sample can also be helpful to determine if a significant proportion of the TPH vapors consists of compounds greater than C12. Vapor-phase TPH data for middle distillate ...
 
...consists of compounds greater than C12. Vapor-phase TPH data for middle distillate release sites that do not include both light- and heavy-end ...
 
...end compounds do not make up a significant proportion (e.g., >10%) of the total vapors. If the lab cannot report lighter-end compounds with their current setup then both �TPHg� ...
 
...a mixture of a high proportion of more toxic, C9-C12 aliphatic compounds in petroleum vapors. These compounds are more typically associated with diesel and other middle distillate fuel ...
 
...compounds are more typically associated with diesel and other middle distillate fuel vapors than vapors from gasoline. As a result, the default action levels may be excessively conservative ...
 
...than vapors from gasoline. As a result, the default action levels may be excessively conservative ...
 
... gasoline. As a result, the default action levels may be excessively conservative for vapor intrusion evaluations of gasoline-only release sites. As discussed in the HDOH EHE guidance ...
 
... levels can also be developed based on the average carbon range makeup of petroleum vapors (refer to HDOH, 2012). Laboratory gas chromatograms should be obtained and included with ...
 
...and action levels are used. This is necessary to ensure that the total concentration of vapor-phase TPH does not pose an unacceptable health risk. This is done by dividing the reported ...
 
...the calibration procedure used by the laboratory. Is calibration done using a liquid or a vapor standard? The latter will provide more accurate data. Were typical gasoline and diesel calibration ...
 
... Therefore, the calibration procedure should be fully documented in the final soil vapor or indoor air investigation report. 7.13.2 Choosing the Analytical Method ...
 
...questions should be considered prior to the selection of analytical methods for soil vapor or indoor air samples (API 2005): What are the targeted chemicals ...
 
...targeted chemicals should be limited to chemicals identified in subslab or subsurface vapor samples. The vapor intrusion risk calculated for indoor air data should be specific to ...
 
...samples. The vapor intrusion risk calculated for indoor air data should be specific to the targeted, subsurface ...
 
...is important to determine the lowest concentrations of chemicals of concern in soil vapor or other analytes that are expected to be required for evaluation of the subsurface ...
 
... other analytes that are expected to be required for evaluation of the subsurface vapor intrusion pathway and general site investigation needs. Refer to the EALs for indoor air ...
 
...field data, indicate that concentrations of chemicals of concern in soil vapor will be high? If concentrations of chemicals of concern or other analytes in soil vapor ...
 
...will be high? If concentrations of chemicals of concern or other analytes in soil vapor are anticipated to be high, then the analytical method selected should address high ...
 
...of VOCs are anticipated, solid waste program methods for analysis of soil vapor samples typically reserved for landfill gas samples may be appropriate (USEPA 1998b). ...
 
...HDOH does not currently require analysis labs in Hawai`i to be certified for soil vapor analyses; however, the HEER Office recommends that lab certifications and/or other lab ...
 
...real time results. Are the analytical methods appropriate for the soil vapor samples? Analytical methods are periodically updated with newer techniques. It is suggested ...
 
...9, it is important to also measure the total petroleum hydrocarbon concentration in soil vapor at petroleum hydrocarbon impacted sites. The total petroleum hydrocarbon measurement should ...
 
... range organics� does not apply to indoor air or soil gas. This is because petroleum vapors from diesel can include a significant and even dominant proportion of lighter, aliphatic compounds ...
 
...The higher, relative volatility of these compounds causes these compounds to dominate vapors associated with diesel and other middle distillate fuels. The currently ...
 
...fuels. The currently preferred laboratory method to test for TPH in soil vapors for final decision making purposes is a combination of both TO-15 (Summa canister samples) ...
 
...with Method TO-17 (or acceptable alternative) are capable of reporting the full range of vapor-phase, hydrocarbon compounds present in a sample, including aliphatics, aromatics and oxygenates. ...
 
...toxic than shorter-chain hydrocarbons and their presence can significantly increase the vapor intrusion risk (HDOH, 2012, see also HDOH, 2016). Documenting the presence or absence ...
 
...Documenting the presence or absence of a significant proportion of these compounds in TPH vapors is necessary at the beginning of a site investigation. The need to continue ...
 
...standard used for the TO-17 method. Document that calibration procedure in the final soil vapor or indoor air investigation report. Detailed TPH carbon range data will ...
 
...Summa vs sorbent tube) and lab method (e.g., TO-15 vs TO-17). For vapors associated with diesel and other middle distillate fuels, sorbent tube methods that are able ...
 
...can quantify naphthalene using TO-15. Detection levels are normally adequate for soil vapor samples in comparison with correlative soil gas action levels (72 to 240 �g/m3), but may be ...
 
...can avoid the need to for multiple samples and laboratory methods, especially for soil vapor samples. Check with the laboratory if indoor air sampling is to be carried out and naphthalene ...
 
... 7.13.3 Field Analytical Methods On-site analysis can be very beneficial for vapor intrusion assessments as real-time data enable detection of preferential vapor migration sources ...
 
...intrusion assessments as real-time data enable detection of preferential vapor migration sources or pathways, allow additional sampling locations to be added (spatially or ...
 
...data and enable measurement of the leak-test tracer compound to ensure valid soil vapor samples are collected. Simple, portable instruments can provide both qualitative and quantitative ...
 
...levels. Field screening with hand-held PIDs or FIDs enable rapid identification of vapor migration routes around and into structures; although most field screening instruments are ...
 
...limited to the ppmv range for VOCs, which often do not provide sufficient sensitivity for vapor intrusion investigations. [Note that PIDs are not very sensitive to aliphatic compounds, which ...
 
... [Note that PIDs are not very sensitive to aliphatic compounds, which dominate petroleum vapors (ASTM 2006f; see also HDOH, 2012). Quantitative oxygen, carbon dioxide, ...
 
...portable GC/MS (e.g. Hapsite by Inficon) is also available and gives quantitative soil vapor and indoor air analysis to levels as low as 1 ppbv. 7.13.4 Quality ...
 
...Stainless steel "T" manifold to simultaneously collect primary and duplicate soil vapor samples in 500-ml Summa canisters. Right photo: Laboratory-supplied duplicate sampling ...
 
...duplicate sampling apparatus to simultaneously collect primary and duplicate soil vapor samples in sorbent tubes. Replicates The use of ...
 
...7.8.4. Concerns regarding the reproducibility and representativeness of small-volume soil vapor samples that represent very small volumes of vapor collected from a single location ...
 
... samples that represent very small volumes of vapor collected from a single location are discussed in Section 7.5. Random variability of VOC ...
 
... are discussed in Section 7.5. Random variability of VOC concentrations in soil vapor at the scale of traditional, small-volume soil vapor sample (e.g., one liter) limits the reliability ...
 
...at the scale of traditional, small-volume soil vapor sample (e.g., one liter) limits the reliability of a single data point to represent ...
 
...surrounding area (Brewer et al. 2014). Large-scale patterns representing the core of a vapor plume can be reasonably identified using a sufficient number of small-volume sample points. ...
 
...number of small-volume sample points. Smaller-scale patterns identified within a vapor plume and based on single samples should be considered suspect, however, and could be artificial ...
 
...methods are intended to help address these limitations of traditional, small-volume vapor sample data. The collection LVP data from other than immediately beneath a building slab or ...
 
...train. Field replicates are not routinely collected for small-volume soil vapor sample investigations but should be considered to confirm plume patterns and VOC concentrations ...
 
...of a sample intended to represent a pre-specified volume of soil or more specifically the vapors held within that soil. Reproducibility is a function of both field and laboratory ...
 
... As discussed in Section 7.6.2.2, approaches for the designation of DUs in terms of soil vapors and vapor intrusion are still being studied. At this time the primary purpose of replicate ...
 
...and vapor intrusion are still being studied. At this time the primary purpose of replicate soil vapor ...
 
...intrusion are still being studied. At this time the primary purpose of replicate soil vapor samples, if collected, is to evaluate the reproducibility of data for individual sample point ...
 
...can provide some information on the spatial variability of VOC concentrations in soil vapor at the scale of the sample volume collected. Collecting larger samples also helps to ensure ...
 
...field duplicate samples can be collected at a minimum of 10% of the active soil vapor or indoor air samples collected per sampling day per laboratory (if more than one laboratory ...
 
...should be included at a minimum of one trip blank per sampling day or shipment cooler for vapor or indoor air samples collected using sorbent tubes or passive samples. Ensure that the laboratory ...
 
...An equipment blank is collected by passing clean air or nitrogen through the soil vapor probe parts (tubing, tips, sample train) into the sample container at the beginning of the ...
 
...contaminants are in the equipment. Equipment blanks are not generally necessary for soil vapor samples, since it is less likely that contamination in tubing or other equipment will in itself ...
 

7.10 Documentation of Soil Vapor or Indoor Air Sampling
...Environmental Hazard Evaluation (EHE) document for guidance on the comparison of soil vapor and indoor air data to published action levels. The interpretation of data is a key element ...
 
...significantly expedite data evaluation and decision making. 7.14.1 Soil Vapor Sample Evaluation The HEER Office EHE document provides risk-based, soil vapor ...
 
...Sample Evaluation The HEER Office EHE document provides risk-based, soil vapor action levels and additional guidance that can be used to screen sites for potential vapor ...
 
...action levels and additional guidance that can be used to screen sites for potential vapor intrusion hazards (HDOH 2017a; see also Sections 7.1 through 7.3). The collection ...
 
...hazards (HDOH 2017a; see also Sections 7.1 through 7.3). The collection of soil vapor data is recommended when the concentration of a VOC exceeds its action level for groundwater, ...
 
... a significant source of VOCs is suspected in vadose-zone soils (Section 13.2). Vapor intrusion action levels for soil are also provided in the HDOH EHE guidance document. Extrapolation ...
 
...in the HDOH EHE guidance document. Extrapolation of the concentration of a VOC in soil vapor from soil data is considered highly unreliable, however, due to the complexities of ...
 
...however, due to the complexities of soil chemistry. LVP subslab vapor data are directly comparable to HDOH (2017a) action levels for vapor intrusion risk. Comparison ...
 
...data are directly comparable to HDOH (2017a) action levels for vapor intrusion risk. Comparison of small-volume soil vapor data, or data representative of only ...
 
...intrusion risk. Comparison of small-volume soil vapor data, or data representative of only small-volumes of vapor collected at individual sample ...
 
...data, or data representative of only small-volumes of vapor collected at individual sample points, to soil vapor action levels should be done with caution ...
 
...collected at individual sample points, to soil vapor action levels should be done with caution and used in conjunction with other lines of evidence ...
 
...with caution and used in conjunction with other lines of evidence to assess potential vapor intrusion risk, especially if LVP data are not available. Be aware that random, small-scale ...
 
...available. Be aware that random, small-scale variability in VOC concentrations within a vapor plume can hinder the interpretation of small-volume sample data (Section 7.5). Reliance on ...
 
...the interpretation of small-volume sample data (Section 7.5). Reliance on small-volume vapor sample data to estimate the approximate large-scale boundaries of a vapor plume is ...
 
... sample data to estimate the approximate large-scale boundaries of a vapor plume is currently necessary, however. Groundwater and soil vapor action ...
 
...plume is currently necessary, however. Groundwater and soil vapor action levels for vapor intrusion are intended to be paired (HDOH 2017a). Empirical data and ...
 
...action levels for vapor intrusion are intended to be paired (HDOH 2017a). Empirical data and corresponding ...
 
...and corresponding models suggest that the concentration of a VOC will not exceed the soil vapor action level at a distance of ten feet (three meters) from the top of the water table. ...
 
... level at a distance of ten feet (three meters) from the top of the water table. Soil vapor data are therefore not normally necessary if vapor intrusion action levels for groundwater ...
 
...data are therefore not normally necessary if vapor intrusion action levels for groundwater are not exceeded and groundwater data can reasonably ...
 
...exceeded and groundwater data can reasonably be assumed to be representative of potential vapor emissions. Unexpectedly high concentrations of VOCs in soil vapor samples collected ten or ...
 
...emissions. Unexpectedly high concentrations of VOCs in soil vapor samples collected ten or more feet from groundwater can usually be attributed to some combination ...
 
...in nearby, vadose-zone soils (most common); Chemical present primarily in vapor phase (e.g., PCE vapors in dry soil beneath slab of a dry cleaner); Groundwater ...
 
... phase (e.g., PCE vapors in dry soil beneath slab of a dry cleaner); Groundwater source area closer than ...
 
...of a dry cleaner); Groundwater source area closer than ten feet from soil vapor sample point (default depth to water table used in models); Non-representative soil ...
 
...data (e.g., heterogeneous plume with isolated �hot spots� nearby); or Relict vapor plume associated with earlier migration of more heavily contaminated groundwater through ...
 
... area releases over time. As discussed in the EHE guidance document, soil vapor data may not be sufficient as a stand-alone tool to determine if a vapor intrusion hazard is ...
 
...data may not be sufficient as a stand-alone tool to determine if a vapor intrusion hazard is present or absent. A �multiple lines of evidence� approach should be used ...
 
...present or absent. A �multiple lines of evidence� approach should be used to evaluate the vapor intrusion pathway. This includes consideration of the following factors, among others: ...
 
...and associated volume of contaminated soil necessary to sustain long-term, vapor emissions over the assumed exposure duration (e.g., six to thirty years; see Section 7.5; ...
 
... six to thirty years; see Section 7.5; can include use of mass-balanced vapor intrusion models); Design of potentially affected buildings and the completeness ...
 
... Design of potentially affected buildings and the completeness of possible vapor intrusion pathways (e.g., cracks, or gaps in the floor around utilities), including nature ...
 
...building to be consistently under-pressured, and thus more susceptible to subsurface vapors; Potential for intruding vapors to impact indoor air above known or anticipated ...
 
... Potential for intruding vapors to impact indoor air above known or anticipated background concentrations of targeted ...
 
... The first two factors are sometimes referred to as �source strength.� For a long-term, vapor intrusion risk to be present, the source strength must be significant enough to sustain an ...
 
...risk to be present, the source strength must be significant enough to sustain an average vapor flux rate above soil gas action levels for the assumed exposure duration (e.g., six to thirty ...
 
...allows investigators to more accurately assess the current or future completeness of the vapor intrusion pathway on a site-specific basis and determine if long-term, adverse impacts to indoor ...
 
...recommends a focus on subslab soil gas data for final decisions regarding potential vapor intrusion risks from multiple compounds, such as chlorinated solvents and petroleum. This is ...
 
...compounds, such as chlorinated solvents and petroleum. This is intended to target vapors at the point they could enter a building. This also takes into account attenuation from the ...
 
...account attenuation from the source area and/or biodegradation. Soil vapor sample analytical results should be initially compared to Shallow Soil Gas action levels for ...
 
...be initially compared to Shallow Soil Gas action levels for evaluation of potential vapor intrusion concerns, published in the EHE document (HDOH, 2016, Table C-2 in Appendix ...
 
...soil gas are approached or exceeded, the need for the collection of additional soil vapor samples and a more thorough evaluation of potential vapor intrusion pathways should be evaluated. ...
 
...samples and a more thorough evaluation of potential vapor intrusion pathways should be evaluated. Indoor air samples may need to be collected if subslab ...
 
...(see Section 7.7). Based on past experience, scenarios where subslab soil vapor data does not suggest a potentially significant impact to indoor air (e.g., above indoor air ...
 
...a potentially significant impact to indoor air (e.g., above indoor air action levels) but vapor sample data from relatively shallow source areas exceed action levels is fairly common, especially ...
 
...of indoor air samples is only recommended when concentrations of VOCs in subslab soil vapor or other information suggest that indoor air could be impacted above anticipated, background ...
 
...background levels. As a general guide, testing of indoor air to evaluate potential vapor intrusion impacts is only recommended when concentrations of targeted chemicals in subslab ...
 
... impacts is only recommended when concentrations of targeted chemicals in subslab soil vapor are more than one-thousand times typical indoor air concentrations for residences and two-thousand ...
 
...above anticipated background levels, significant VOC levels have been documented in soil vapor samples collected immediately beneath the building slab, and clear entry points have been identified. ...
 
...be reviewed and compared to help identify contaminant concentration gradients or specific vapor intrusion points. For example, data for basements, bathrooms, kitchens, utility rooms or elevator ...
 
... If impacts to indoor air above anticipated background are identified and subslab soil vapor data as well as other lines of evidence suggest a likely subsurface source, then actions will ...
 
...If impacts to indoor air above anticipated background are not identified but subslab soil vapor concentrations exceed action levels, then measures to avoid potential future impacts to indoor ...
 
...of the building ventilation system may simply be recommended in cases where subsurface vapors are associated with a relatively small source area of petroleum-contaminated soil or groundwater. ...
 
...petroleum-contaminated soil or groundwater. In contrast, measures to eliminate potential vapor pathways might be required at a site where elevated concentrations of chlorinated solvents ...
 
...might be required at a site where elevated concentrations of chlorinated solvents in soil vapors associated with a large source area are identified immediately beneath a building slab or ...
 
... area are identified immediately beneath a building slab or in nearby, shallow soil vapor, even though adverse impacts to indoor air have not been specifically identified. ...
 
...If impacts to indoor air above anticipated background are not identified and subslab soil vapor concentrations do not exceed action levels, then no further action will generally be required ...
 
...to the subject home building. If subsurface data indicate a potentially significant vapor plume, however, then sealing of cracks and utility gaps in floors and an evaluation of the ...
 
...of clear impacts to existing buildings if source area soil, groundwater and/or soil vapor data suggest potential future vapor intrusion risks or other environmental hazards. Refer also ...
 
...data suggest potential future vapor intrusion risks or other environmental hazards. Refer also to the HDOH technical memorandum ...
 
... As a general rule a home or building should not be flagged for potential vapor intrusion hazards unless this is supported by multiple lines of evidence, including indoor ...
 
...it is more appropriate and responsible to state that �Conclusive evidence of adverse, vapor intrusion has not been documented� than an open-ended statement such as �Vapor intrusion into ...
 
...intrusion has not been documented� than an open-ended statement such as �Vapor intrusion into the home (or building) could not be discounted.� Due to the sensitivity of testing ...
 
...sources, an �innocent until proven guilty� approach for the investigation of potential vapor intrusion hazards is recommended. Precautionary measures are recommended, however, ...
 
...however, for sites where significant subsurface source exists even though adverse, vapor intrusion impacts have not been identified. As discussed above, this will typically include ...
 
... the limitations described in the EHE document (HDOH, 2016), VOCs in groundwater or soil vapor below the corresponding Tier 1 EALs can be assumed to not pose a significant vapor intrusion ...
 
...below the corresponding Tier 1 EALs can be assumed to not pose a significant vapor intrusion threat. If multiple lines of evidence such as those noted above indicate ...
 
...or remedial actions will be warranted. This will typically include the removal of vapor intrusion pathways for existing buildings (e.g., sealing of cracks and gaps in floors, etc.) ...
 
...gaps in floors, etc.) and remediation of contamination in the source area to reduce soil vapor levels to below levels of potential concern. An evaluation of the adequacy of the building ...
 
... and Assessment Model (USEPA 2008d). A detailed review of site-specific vapor intrusion risks can also be carried out if desired and can include the preparation of site-specific ...
 
...desired and can include the preparation of site-specific human health risk assessments, vapor intrusion models and alternative action levels. This level of effort is unlikely to be necessary ...
 
...small sites, however. A detailed discussion of source area remediation and vapor mitigation is beyond the scope of this section but will be included in future updates to the ...
 
...soil beneath the floor of a former dry cleaner. Some combination of excavation, soil vapor extraction, in situ injections, or thermal treatment might be required for a site with extensive ...
 
...In some cases the installation of a subslab ventilation system could be required. A vapor mitigation system for a new structure might include one or more of the following components ...
 
...with wind-activated turbine vents and option for blowers, etc.); and Permanent soil vapor monitoring points through slab and within collection system. Passive ...
 
...to address methane hazards or the buildup of very high levels of solvent or petroleum vapors beneath the slab. Monitoring points within the slab and collection system can be used to evaluate ...
 
... flow in risers, and to support proposals to cease mitigation effects due to a reduced vapor intrusion risk. ...
 

7.10 Documentation of Soil Vapor or Indoor Air Sampling
... ' 7.15 DOCUMENTATION OF SOIL VAPOR OR INDOOR AIR SAMPLING A soil vapor or indoor air investigation report should be ...
 
...OR INDOOR AIR SAMPLING A soil vapor or indoor air investigation report should be submitted to the HEER Office for review following ...
 
...for Investigation Reports is included in Section 18. The submittal of a workplan for soil vapor and/or indoor air investigations is also strongly encouraged. The soil ...
 
...indoor air investigations is also strongly encouraged. The soil vapor or indoor air investigation report should include a thorough description of all field operations, ...
 
...or laboratory analytical flags) and an analysis and interpretation of the data. All soil vapor or indoor air investigation reports should include a site plan map identifying soil vapor or ...
 
...or indoor air investigation reports should include a site plan map identifying soil vapor or indoor air sampling locations. The relative location of soil and groundwater contamination ...
 
...proposed future buildings should also be depicted on the figures. Field activities during vapor point installation and sample collection should be fully documented in the final investigation ...
 
... should be fully documented in the final investigation report. For sites where soil vapor or indoor air samples are collected from permanent probes, the probe construction details should ...
 
...of LVP sample data is summarized in Section 7.8.4. The soil vapor or indoor air analytical data should be summarized and presented on a table that facilitates ...
 

9.4 Methane
... Methane Monitoring Conduit Seals and Utility Trench Dams Vapor Mitigation Methane Monitoring Conduit Seals ...
 
... Methane Monitoring Conduit Seals and Utility Trench Dams Vapor Mitigation 0 - ...
 
... Methane Monitoring Conduit Seals and Utility Trench Dams Vapor Mitigation 100 ...
 
...of buildings with cracked floors, gaps around utility penetrations in the floor or other vapor entry routes could also pose potential hazards. Figure 9-1 presents a ...
 
...and mitigation actions for site where high levels of methane are detected in soil vapors (Geosyntec 2011). Final monitoring and mitigation actions for potential ...
 
...(CalEPA 2005b). Be aware that high levels of light-end (C5-C12), petroleum vapors can cause false, elevated readings of methane in vapor samples using a standard, landfill ...
 
...can cause false, elevated readings of methane in vapor samples using a standard, landfill gas analyzer. The use of a carbon trap is recommended when ...
 

Appendix 4-A1 Volatile Chemicals Requiring Field Preservation Of Soil Sample Increments
...     2Vapor Pressure Henry's Law Constant (H) ...
 
...if H > 0.00001), S - solid, L - liquid, G - gas). Vapor Pressures from National Library of Medicine TOXNET or ChemID databases. ...
 

Appendix 4-A1 Volatile Chemicals Requiring Field Preservation Of Soil Sample Increments
...     2Vapor Pressure Henry's Law Constant (H) ...
 
...if H > 0.00001), S - solid, L - liquid, G - gas). Vapor Pressures from National Library of Medicine TOXNET or ChemID databases. ...
 

Appendix 4-A2 Volatile Chemicals Requiring Field Preservation Of Soil Sample Increments
...     2VaporPressure Henry's Law Constant (H) ...
 
...if H >0.00001), S - solid, L - liquid, G - gas). Vapor Pressures from National Library of Medicine TOXNET or ChemID databases. ...
 

13.7 HUMAN HEALTH RISK ASSESSMENTS
...Tables (USEPA, 1997) Assessing the Significance of Subsurface Contaminant Vapor Migration to Enclosed Spaces (Johnson et. al, 1998) Supplemental Guidance ...
 

9.6 Methamphetamine Laboratory Cleanup
... Flammable Toxic Vapors Explosive ...
 
... X   Burns, toxic vapors Phosphine Gas ...
 

5.10 Investigation Derived Waste
... Pour onto ground in area where samples were collected to allow infiltration or evaporation; Transport to a HDOH-permitted off-site treatment/disposal facility. ...
 

8.2 DATA QUALITY CONTROL AND DOCUMENTATION
...8.4.2 and 8.4.5). Some PIDs can be used to measure both total VOCs in vapors emitted from soil as well as concentrations of a limited number of individual compounds (e.g., ...
 

8.4 FIELD SCREENING METHODS FOR SELECT CONTAMINANTS AND MEDIA
...soil tested; Potential under reporting of TPH concentration due to evaporation of volatile petroleum hydrocarbon mixtures such as gasoline during test procedure. ...
 
... an ultraviolet fluorescence spectrophotometer. The fluorometer uses a mercury vapor lamp as its light source. Petroleum compounds in soil sample are mixed and extracted ...
 
...as sample containers (e.g., Associated Bag Company Item #183-52) in order to minimize vapor loss during the recommended fifteen- minute equilibration period. ...
 
...and JP-8) or when the fuel type is unknown. This corresponds to anticipated lower vapor emissions from soils containing 100 mg/kg TPHd in comparison to gasoline-contaminated soils, ...
 
... light-end aromatics and aliphatic compounds in these fuels (assumed 10% of gasoline vapor emissions; see also HDOH, 2012). Consultants report that PID readings below 10ppmv are ...
 
...volatile aromatic compounds. PIDs are not good indicators of total TPH levels in soil vapors because they do not respond well to aliphatic volatile compounds, which dominate vapors ...
 
...because they do not respond well to aliphatic volatile compounds, which dominate vapors from petroleum fuels (refer to Section 7 and Section 9). ...
 
...than for an equivalent concentration of gasoline due to low, aromatic content of vapors. Requires use of a container that minimizes loss of volatile chemicals ...
 

8.5 FIELD SCREENING WITH CONE PENETROMETER AND SENSORS/PROBES
...or pneumatic hammer to drive the MIP to the depth of interest to collect samples of vaporized compounds. The probe captures the vapor sample, and a carrier gas transports the sample ...
 
...compounds. The probe captures the vapor sample, and a carrier gas transports the sample to the surface for analysis by a variety ...
 
...dry electrolytic conductivity [DELCD] detectors) that establish the presence of VOC vapor, dissolved phase LNAPL, or DNAPL in soil. These detectors may be deployed singly or in ...
 

8.6 FIELD SCREENING EQUIPMENT TO SUPPORT HEALTH AND SAFETY PROGRAMS
...industrial hygienist. Weather conditions such as extreme heat or cold, humidity (water vapor), exposure to rain or other spilled liquids, and electromagnetic radiation can all affect the ...
 
...typically uses a platinum filament, which is heated by burning the combustible gas or vapor. The increase in heat is measured and reported as a percent of the lower explosive limit ...
 
... Measures the presence of combustible gases/vapors Range : 0 � 100 % of LEL (units are % of the LEL or ppm depending on ...
 
... in hydrogen flame Can detect compounds with high ionization energy vapors (such as methane). Limitations Can ...
 
... instrument response Does not detect methane and other vapors with high ionization energy Multiple sensitivities (multiple electron ...
 

PDF Download Page
...   Section 7 - Soil Vapor and Indoor Air Sampling Guidance ...
 
... Field Investigation of the Chemistry and Toxicity of TPH in Petroleum Vapors: Implications for Potential Vapor Intrusion Hazards. ...
 
...Implications for Potential Vapor Intrusion Hazards.   (HDOH 2011d) ...