2.1 State Contingency Plan
...of a variety of waste, accidentally spilled substances, abandoned materials,
soil, groundwater, surface water, air, and leaking underground tanks may be addressed
through the Hawai`i ...
2.3 Emergency Response
...functioning
vessel engine are exempt)
Any free product that appears on groundwater
Any amount of oil greater than 25 gallons released to the environment
Any amount of ...
2.4 Environmental Cleanups
...cases complex environmental cleanups involving multiple contaminants
and both soil and groundwater contamination can involve years of effort before the
site is adequately cleaned up and closed.
...
...soils are discovered
and removed during an emergency response, but some sub-soil or groundwater contamination
still remains
Groundwater contamination discovered in a non-drinking ...
...contamination
still remains
Groundwater contamination discovered in a non-drinking groundwater aquifer located
below a former gasoline ...
...contamination discovered in a non-drinking groundwater aquifer located
below a former gasoline service station
A Phase II Environmental ...
...II Environmental Site Assessment required by a financial institution reveals
soil or groundwater contaminated with a hazardous substance above HEER Office Environmental
Action Levels
...
...they have typically aged, weathered, absorbed, or dispersed into
the soil, or diluted in groundwater to the point that the contamination present
does not pose a significant short-term hazard. ...
...soil staining or sampling data indicated the potential for remaining subsurface
or groundwater contamination
An overview of the discovery, assessment, and cleanup steps for non-emergency ...
...releases are usually identified when environmental samples
(typically soil and/or groundwater) are collected at a site, and sample analysis
shows Tier 1 EAL exceedances. These exceedances ...
...substance releases, including actual
or probable releases to:
Groundwater that is a drinking water supply
Surface water that is a drinking water supply
Groundwater ...
...that is a drinking water supply
Surface water that is a drinking water supply
Groundwater or surface water that is not a drinking water supply
Air that poses a threat to public health
...
...such as leaking containers or impoundments
Soil, soil gas, indoor air, groundwater, or surface water that has contamination
levels exceeding HDOH Tier 1 EALs
Adverse ...
...The goal of a
site assessment is to identify and remediate contaminated soil and groundwater that
poses unacceptable environmental hazards, either under current site conditions or
...
...The investigation is carried out by the collection and analysis of samples
of soil, groundwater, soil gas, surface water, sediment, air and/or other media
as needed (see Sections 4 through ...
...or absence of potential hazards
may simply be identified and the contaminated soil or groundwater quickly remediated
without further assessment. In cases where remedial costs could be significant ...
...Section 13
and Evaluation of Environmental Hazards at Sites with Contaminated Soil and Groundwater,
HDOH, 2016).
This will help make the final EHE more site-specific and ensure that ...
... Cause of release or threat
Site history
General site geology, hydrology, groundwater status, adjacent land uses
Distance to surface water bodies
Situation preceding decision ...
2.5 Site Closure
...address contamination
that may remain at the site (e.g., in the subsurface soil or groundwater). In these
instances, the NFA letter will indicate that the emergency response has been appropriately
...
...Office guidance for Long-Term Management of Petroleum-Contaminated
Soil and Groundwater, responsible parties may request the HEER Office to issue a
determination that "No Further ...
3.0 Site Investigation Design And Implementation
... as needed.
For example, detection of high levels of tetrachloroethylene in groundwater during
a site investigation could suggest vapor intrusion as a potential environmental
...
...investigation could suggest vapor intrusion as a potential environmental
hazard (e.g., groundwater action level for vapor intrusion exceeded). This could
trigger the collection of soil gas samples ...
3.1 Site Investigation Scoping
...up on Phase I findings through the collection, analysis and
evaluation of soil, groundwater, soil gas or other types of environmental samples
(e.g., lead and asbestos testing of building ...
... maps and area-wide descriptions of geology, soil types, topography, and groundwater
conditions);
Historical use sources (e.g., aerial
photographs, ...
3.2 Systematic Planning Of Site Investigation
...progression of environmental investigations at sites with contaminated soil
and groundwater.
Preparing DQOs prior to the initiation of field activities should ...
... Do preliminary data indicate the
presence of contaminants in soil, groundwater or other environmental media greater
than the HDOH Tier 1 Environmental Action Levels ...
...environmental hazards at a site
(e.g., direct exposure, vapor intrusion, leaching to groundwater, etc.). The site
investigation must be designed to meet this objective, as well as to provide ...
...exposure risk to residents?
Is the size of the benzene plume
in groundwater increasing, stable or shrinking?
Does the contamination at the site
extend ...
...presence of debris or fill material, location of utilities, depth to and use
of groundwater, location and types of other manmade structures, etc.
Identify nearby water supply wells,
...
...found
in Evaluation of Environmental Hazards at Sites with Contaminated Soil and Groundwater
(HDOH 2016).
Step 3—Identify Data Needs
...
... What types of media should be collected
and analyzed (e.g., soil, soil gas, groundwater, surface water, etc.) based on areas
and types of potential contamination?
...
...etc.) based on areas
and types of potential contamination?
For groundwater, how often will sampling
need to be repeated, and how will samples for specific contaminants ...
...of
soil gas samples.
Concurrent collection of groundwater data should be considered at sites where soils
are grossly contaminated with highly mobile ...
...or the
type of contaminants present could otherwise pose significant leaching and groundwater
contamination hazards (e.g., herbicides, such as atrazine). In other cases, additional
...
...
Collection of soil gas data at sites
where initial soil and/or groundwater data indicate potential vapor intrusion hazards.
Analysis of soil samples ...
...the target contaminant is highly leachable from the soil and could pose a threat
to groundwater resources or is highly volatile and could pose potential vapor intrusion
hazards for buildings ...
...the driving environmental hazard
is often direct exposure, rather than leaching and groundwater protection (e.g.,
arsenic, lead, PCBs, polychlorinated dibenzodioxins and polychlorinated ...
... Section 5.
Issues to consider in developing the SAP for soil, groundwater, soil gas and other
targeted media include:
How can sample ...
... what is the minimal well size needed to collect the necessary amount of groundwater
for sample analyses, given the site geology (e.g., micro-wells may not allow the
...
...sample collection methods are discussed in Sections
4 and 5. The collection of groundwater samples
is discussed in Section 6. Soil gas and indoor air sampling
is discussed ...
...testing)
on the samples to better evaluate contaminant mobility and the threat to groundwater.
These possible outcomes should be identified in advance under Step 3 and contingencies
...
...field staff
at the anticipated or potential concentrations in soil, soil gas and groundwater?
What physical site conditions could
pose hazards to field ...
...
A summary of common environmental hazards posed by contaminated soil and groundwater
is provided in Figure 3-5. Site investigations and Environmental Hazard Evaluations
...
...to evaluate contaminant mobility (HDOH, 2007,
2016) and/or the collection of groundwater data (Section 6)?
Do reported concentrations of COPCs
in soil or groundwater ...
...data (Section 6)?
Do reported concentrations of COPCs
in soil or groundwater data present potential vapor intrusion concerns, indicating
the need for soil gas or ...
... excavation activities?
Do high levels of contaminants in
groundwater indicate potential impacts to nearby aquatic habitats, suggesting the
need to collect ...
...impacts to nearby aquatic habitats, suggesting the
need to collect additional groundwater, sediment or surface water data?
Do high levels of COPCs in soil and
groundwater ...
...sediment or surface water data?
Do high levels of COPCs in soil and
groundwater pose a threat to offsite migration which could lead to contamination
of adjacent properties?
...
3.3 Conceptual Site Models
...of common environmental
hazards associated with contaminated soil and groundwater as well as potential exposure
pathways for human and ecological receptors.
...
...a pictorial depiction of environmental hazards associated with
contaminated soil and groundwater (see also Figure 3-5).
Exposure pathways to human and ecological receptors are also indicated ...
...this includes a summary of the known or suspected extent
and magnitude of soil and groundwater contamination. In addition, site conditions
such as land use, groundwater use, potential ...
...contamination. In addition, site conditions
such as land use, groundwater use, potential onsite and offsite receptors, exposure
or isolation of contaminated soil, ...
...posed by the COPC. Common environmental hazards associated
with contaminated soil and groundwater (Figures 3-5
and 3-6) include:
Contaminated Soil:
...
...vapors to
building interiors;
Leaching and contamination of groundwater
resources;
Impacts to terrestrial habitats (terrestrial
...
...odors, general resource degradation, etc.);
Contaminated Groundwater:
Contamination of drinking water resources
(toxicity, ...
...subsurface vapors to
building interiors;
Discharges of contaminated groundwater
to surface water aquatic habitats (aquatic ecotoxicity or gross contamination conditions);
...
...document Evaluation
of Environmental Hazards at Sites with Contaminated Soil and Groundwater
(HDOH 2016).
These environmental hazards form the basis ...
...Four default
CSMs or site scenarios are provided for in the Tier 1 EALs, depending on groundwater
utility and location of a subject site with respect to nearby surface water bodies
...
...(see Section 13). Only surface water
bodies that are hydraulically connected to groundwater are considered to be potentially
threatened by contaminated groundwater. This could include ...
...are considered to be potentially
threatened by contaminated groundwater. This could include streams, drainage ways,
or even leaky storm sewers that lead to a surface ...
...to aquatic habitats, storm sewers in direct hydraulic connection
with contaminated groundwater are considered to represent a "surface water body"
for initial screening purposes. Measuring ...
...body"
for initial screening purposes. Measuring the piping invert in relation to the groundwater
table at high-high tides and the presence or absence of free product at the discharge
...
...could be significant, or at sites where long-term management of contaminated
soil or groundwater will be required. A closer evaluation of current and future
risks to human or ecological ...
...boundaries;
Area of contaminated soil is paved;
Underlying groundwater is not a current
or potential source of drinking water;
Site is located ...
...that the pathway for leaching of contaminants from
soil and contamination of groundwater is complete, because contaminated soil is
in direct contact with groundwater, even though ...
...is complete, because contaminated soil is
in direct contact with groundwater, even though the area is assumed to be capped
with pavement. This is used to support the ...
...area is assumed to be capped
with pavement. This is used to support the collection of groundwater data to more
directly evaluate impacts and potential concerns. Removal of pavement could ...
...and potential concerns. Removal of pavement could also
exacerbate leaching and groundwater contamination due to infiltrating rain or irrigation
water. This could require the maintenance ...
... The more detailed CSM may be used to support a conclusion that contaminated soil
and groundwater does not pose unacceptable environmental hazards under current site
conditions. Depending ...
...area of contaminated soil remain capped, that a health and safety
plan and soil and groundwater management measures be developed prior to any subsurface
construction activities at the ...
... construction activities at the site, and that the need for long-term monitoring
of groundwater be further evaluated. Actions related to restricted-use site closure,
and the preparation ...
...potential environmental
hazards, including leaching and potential contamination of groundwater (refer to
Figure 3-5; see also Section 13).
As discussed in Sections 2, 3
...
...with other relevant information):
Additional soil, soil vapor or groundwater
data;
Location of existing monitoring wells
and past ...
...(preferably based on decision unit and Multi Increment
sample data);
Groundwater contamination summary
figures with areas above EALs highlighted;
Soil ...
...summary figures with
areas above EALs highlighted;
Direction of groundwater flow, depth
to groundwater;
Cross sections that depict the site
...
...flow, depth
to groundwater;
Cross sections that depict the site
stratigraphy as well as the lateral ...
3.4 Selection Of Decision Units
...document Evaluation of Environmental Hazards at Sites with Contaminated
Soil and Groundwater (HDOH 2016).
3.4.1 DECISION UNIT DESIGNATION
...
...should be selected to characterize
the area. DUs for different media (e.g. soil vs. groundwater vs. soil gas vs. indoor
air) should in most cases be treated separately, even if they are ...
...multiple environmental
hazards, including leaching of contamination to subsurface groundwater resources,
intrusion of vapors into overlying buildings and nuisance or even explosion ...
...or other chemicals
that could migrate downwards and contaminate deeper soil or groundwater. A subsurface
investigation may also be required to further delineate contamination documented
...
...chemicals (e.g.
explosives residues) can also pose potential leaching threats to groundwater that
might be used to serve the redevelopment in the future.
...
...guidance Evaluation of Environmental Hazards at Sites with Contaminated
Soil and Groundwater (HDOH 2016). When using
a Decision Unit strategy, the entire area of a Decision Unit is ...
3.5 Example Decision Units
...from approximately 1,000 ft2
to 2,000 ft2. These areas primarily pose leaching and groundwater impact
hazards.
Subsurface DU layers designated for the ...
...water during rain events, as well as leaching of salt and
impacts to underlying groundwater. (Note that while a high sodium content can inhibit
leaching and runoff, this will also ...
3.6 Sampling And Analysis Plans
... Section 4.3).
See Section 6 for sample collection strategies for groundwater,
and Section 13 for information and references regarding
ecological risk evaluations.
...
...be useful
for a given site. Sampling method procedural guidance for soil and sediment, groundwater
and surface water, and soil vapor and indoor air is presented in
Sections 5, ...
3.8 Data Quality Assessment
...if sampling
did not delineate the vertical or horizontal extent of contamination, or if groundwater
was not encountered due to drilling refusal at a site where groundwater was believed
...
... was not encountered due to drilling refusal at a site where groundwater was believed
to be impacted; then additional sampling would typically be required.
...
3.9 Site Investigation Reports
...18. The HEER Office requires that the lateral and, as needed, vertical
extent of soil and groundwater (and in some cases soil gas) contamination be clearly
depicted on to-scale maps and cross sections ...
3.10 Environmental Hazard Evaluation
...HDOH document Evaluation of Environmental Hazards at Sites with Contaminated
Soil and Groundwater (HDOH 2016). An overview
of the document is provided in Section 13.
As ...
...to identifying potential environmental
hazards associated with contaminated soil or groundwater is a direct comparison
of site data to the HDOH Tier 1 EALs (see Section 13).
...
... of a COPC exceeds the Tier 1 EAL in the subject media (e.g., soil, soil gas, or
groundwater) then the specific environmental hazard(s) potentially posed by the
chemical should be identified ...
...of potential leaching hazards associated with
a COPC suggests that batch testing and/or groundwater data may be needed. The identification
of potential vapor intrusion concerns suggests that ...
4.2 Use Of Multi Increment Samples To Characterize DUs
...soil
should normally be accompanied by the concurrent or followup collection of groundwater
(Section 6) and/or soil vapor samples (see
Section 7). Volatile chemicals ...
...intrusion hazards. These concerns can be more directly addressed through testing
of groundwater and soil vapors.
4.2.4 INCREMENT DISTRIBUTION
...
...with diesel and other middle distillate fuels is no
longer required (tested for groundwater only; refer to Section
9). Note also that naphthalene can be reported under most VOC ...
... potential vapor intrusion hazards associated with volatile contaminants in soil
(and groundwater). Soil gas data are also very useful for identifying and locating
areas of heavy contamination. ...
...document Evaluation of Environmental
Hazards at Sites with Contaminated Soil and Groundwater (HDOH
2016) and Section 7 of this TGM for additional
information.
...
...leachable contaminants
are found in surface soils above HDOH EALs;
Groundwater data suggest that a release
has occurred and contamination has migrated through the ...
...example the collection of soil gas samples for
volatile contaminants or testing of groundwater for contaminants that pose potential
leaching hazards. Sampling constraints and potential ...
5.1 Initial Site Inspection
... likely to be encountered in the subsurface, as well as the anticipated depth to
groundwater. Direct push rigs are preferable for the collection of continuous cores
and subsurface Multi ...
5.4 Subsurface Soil Sample Collection
...ideal for
MI sampling strategies. Push rigs can also be used to collect soil gas or groundwater
samples. Soil gas sampling is discussed in Section 7. The
use of push rigs ...
...in Section 7. The
use of push rigs to install small-diameter monitoring wells for groundwater collection
is discussed in Section 6.2. Smaller track-mounted rigs
could be ...
5.8 Field Documentation
...vesicles in either
lava type. All of these may indicate preferential pathways for groundwater travel.
Tuff (T) � Descriptions of tuff should
include boring ...
...of rock type should pay primary attention to characteristics
that potentially affect groundwater behavior (e.g. basalt fracturing, carbonate
porosity). An example rock description is as ...
6.0 Groundwater and Surface Water Sampling Guidance
... '
SECTION 6
GROUNDWATER AND SURFACE WATER SAMPLING GUIDANCE
Interim Final-December 31, 2008
...
Contents
...
6.0
Groundwater and Surface Water Sampling Guidance
...
...
6.1
Groundwater Monitoring Well Placement
...
...
6.1.1
Initial Groundwater Investigation Phase
...
...
6.3
Groundwater Gauging
...
...
6.5
Groundwater Sample Collection Methods
...
...
6.5.7
Order of Groundwater Sampling
...
...
6.6
Filtration of Groundwater Samples
...
...
6.8
Groundwater Modeling
...
...
6-1
Diagram of a Typical Groundwater Monitoring Well
...
...
6-11
Example Groundwater Sampling Log
...
...
6-15
Bailers for Purging and Groundwater Sampling
...
...
Potential for Representative Analytical Results for commonly Utilized Groundwater
Sampling Methods for Common Contaminants of Potential Concern
...
6.0 Groundwater and Surface Water Sampling Guidance
... '
6.0 GROUNDWATER AND SURFACE WATER SAMPLING GUIDANCE
The sampling guidelines presented in this section ...
...part of an environmental investigation are representative of
the in-situ condition of the groundwater or surface water, and that data derived
from these samples can be used for decision making ...
...sampling, as well as an
overview of sampling equipment available for the collection of groundwater or surface
water samples.
This section refers to information in other TGM sections ...
...
This section refers to information in other TGM sections that are relevant to groundwater
and surface water sampling. For instance, site investigations may sometimes feature
...
... and surface water sampling. For instance, site investigations may sometimes feature
groundwater as the sole media of concern, but groundwater sample collection is most
frequently performed ...
...as the sole media of concern, but groundwater sample collection is most
frequently performed as part of a larger investigation that also ...
Figures
...
6-1
Diagram of a Typical Groundwater Monitoring Well
...
...
6-11
Example Groundwater Sampling Log
...
...
6-15
Bailers for Purging and Groundwater Sampling
...
Tables
...
Potential for Representative Analytical Results for commonly Utilized Groundwater
Sampling Methods for Common Contaminants of Potential Concern
...
6.1 Groundwater Monitoring Well Placement
... '
6.1 GROUNDWATER MONITORING WELL PLACEMENT
The SAP must identify the site-specific monitoring well design ...
...Section 3) that describe the site topography, the geologic
setting, and the presumed groundwater hydrology
The area of environmental concern
The contaminants of potential concern
...
...as potable water supply wells, irrigation wells, and surface
streams connected to groundwater
Influences on hydrology such as injection wells or tidal fluctuation
...
...on hydrology such as injection wells or tidal fluctuation
6.1.1 Initial Groundwater Investigation Phase
The initial investigation phase described in this section assumes ...
...conditions: (1) a single point source or area
of suspected contamination, and (2) prior groundwater investigation has not been
conducted.
The preliminary conceptual model (see ...
...from published reports such
as the Aquifer Identification and Classification Reports: Groundwater Protection
Strategy for Hawai`i (Mink, J.F. and L.S. Lau, 1990a;
1990b; 1992; ...
...whether contaminants have impacted
the uppermost water bearing zone including perched groundwater. During this phase,
a minimum of three wells are required for each known or suspected contaminant ...
...angles relative to one another, will
provide sufficient data to establish the local groundwater flow direction through
static groundwater level measurements.
Place at least ...
...flow direction through
static groundwater level measurements.
Place at least one of these wells in proximity to the source area ...
...the initial investigation phase, the well screens must extend across the
water table and groundwater sampling must include the uppermost water bearing zone,
including perched groundwater. Monitoring ...
...sampling must include the uppermost water bearing zone,
including perched groundwater. Monitoring wells with screens extending across the
water table are typically installed with ...
...and 3 feet of screen interval above the water
table. This allows for the assessment of groundwater level fluctuations as well
as the accumulation of free product on the water table surface.
...
... wells may be required to delineate the horizontal and/or vertical extent of the
groundwater contamination plume. In general, contamination resulting from petroleum
products (which are ...
...are denser than water,
and sink).
To delineate the horizontal extent of groundwater impacts, monitoring wells are
installed cross gradient, up gradient, and down gradient of the ...
...important if one or more contaminants of concern occur naturally
in the soil and groundwater at the site.
To delineate the vertical extent of groundwater impacts, monitoring wells ...
...at the site.
To delineate the vertical extent of groundwater impacts, monitoring wells are installed
with successively deeper screen intervals. Screen intervals ...
...of any confining units between upper and lower aquifers to
prevent the vertical spread of groundwater contamination. When possible, drill to
and collect geotechnical samples from the confining ...
6.2 Monitoring Well Installation and Abandonment
... determination of the potential presence, extent, and movement of contaminant plumes
in groundwater, as well as the assessment of aquifer characteristics (for use in
groundwater models). Monitoring ...
...as well as the assessment of aquifer characteristics (for use in
groundwater models). Monitoring wells must therefore facilitate hydrologic testing
and facilitate the collection ...
...therefore facilitate hydrologic testing
and facilitate the collection of representative groundwater samples. There is no
"typical" monitoring well for achieving this objective.
...
...construction and materials are a function of the anticipated nature
of the contaminants, groundwater quality, desired sampling depth(s), the aquifer's
lithology and its overburden, the borehole ...
...a shallow or smaller diameter well.
To ensure that samples are representative of groundwater conditions, monitoring
well design should reflect anticipated contaminant properties. For example, ...
...bearing units.
6.2.1 Permanent Monitoring Wells
All permanent groundwater monitoring wells have certain design components in common
(USEPA, 1991a). A schematic of a ...
...wells have certain design components in common
(USEPA, 1991a). A schematic of a standard groundwater
monitoring well is presented in Figure 6-1. The monitoring well design components
...
...protection
Figure 6-1. Diagram of a Typical Groundwater Monitoring
Well
This illustration shows the screen interval across the water table, ...
...solid well riser and a well screen, which keeps
the borehole open and provides access to groundwater for the collection of a water
sample. The casing should always include a bottom cap to exclude ...
... depending on the objective of the well installation (e.g., site investigation or
groundwater remediation) and the proposed monitoring and test equipment. When practical,
the casing diameter ...
...exceed 4 inches to avoid generating large volumes
of potentially contaminated soil and groundwater requiring management and disposal
during well installation, development and purging activities. ...
...(USEPA,
1991a; CalEPA, 1995b).
The casing material must not alter the groundwater chemistry by leaching, sorbing
or desorbing
It must be strong enough to withstand ...
...consisting of clean silica sand is installed around the
well screen and allows groundwater to flow into the monitoring well for the collection
of groundwater samples.
...
...to flow into the monitoring well for the collection
of groundwater samples.
Figure 6-3. Hollow Stem Auger with PVC ...
... (ASTM, 2004a).
Handbook of Suggested Practices for the Design and Installation of Groundwater-Monitoring
Wells (USEPA, 1991a).
Test Methods for Evaluating Solid Waste, Volume ...
...the filter
pack material (USEPA, 1991a). For typical investigations
of shallow groundwater in Hawai`i, a 2-inch diameter PVC casing with a screen
slot size of 0.020 inches combined ...
... and 3 feet of screen interval above the water table. This allows for the assessment
of groundwater level fluctuations as well as the accumulation of free product on
the water table surface.
...
...A solid riser below
the screen may lead to stagnant environments, which may alter the groundwater chemistry
(USACE, 1998).
The total borehole depth should not be more than 1 ...
...below the planned bottom
of the monitoring well in order to avoid preferential vertical groundwater flow
originating from below the well screen. If a borehole extends greater than 1 meter
...
...of the well screen to 2 to 5
feet above the well screen, if feasible. In areas of shallow groundwater, a site-specific
plan is recommended before installation of the wells begins. The filter pack ...
...bentonite seal, if feasible,
is installed above the filter pack. In areas of shallow groundwater, a site-specific
plan is recommended before installation of the wells begins. Pelletized bentonite
...
... 6.2.1.6 Well Survey
All wells being used to assess the hydraulic gradient and the groundwater flow direction
must be surveyed by a licensed professional surveyor. Record the well locations
...
...pack, and adjacent formation such that the resulting inflow
is representative of the groundwater flow in the surrounding aquifer.
Final well development proceeds after well installation ...
...from the screen,
filter pack and adjacent formation. Surging is alternated with groundwater pumping
to remove groundwater and sediment accumulated in the well during surging. Use of
...
...pumping
to remove groundwater and sediment accumulated in the well during surging. Use of
a vented, rather than un-vented, ...
...particulates stuck in the well
screen and filter pack. Backwashing is alternated with groundwater pumping to remove
groundwater and the sediment suspended in the groundwater due to well development.
...
...pumping to remove
groundwater and the sediment suspended in the groundwater due to well development.
A combination of surging, ...
...and the sediment suspended in the groundwater due to well development.
A combination of surging, backwashing, and pumping may be used to ...
...the well screen, filter pack and adjacent formation. Hydraulic jetting is alternated
with groundwater pumping to remove groundwater and sediment accumulated in the well
by jetting.
...
...pumping to remove groundwater and sediment accumulated in the well
by jetting.
When using water during drilling, ...
... per liter.
The well water is clear to the unaided eye, in areas where the local groundwater
is known to be clear and the turbidity readings are below 10 nephelometric turbidity
...
...±10 percent at concentrations larger than
10 NTU. In areas of known turbid groundwater, the final well water may be turbid
to the eye.
The sediment thickness in the ...
...log for each monitoring well. ASTM Standard D5521 (ASTM, 2005a) presents additional guidance on groundwater
well development. An example well development log is illustrated on Figure 6-8.
...
...later than 7 days after
well completion.
The HEER Office recommends that groundwater gauging, purging and sampling be conducted
no sooner than 14 days after well development. The ...
...Guidance from other agencies for the
time interval between monitoring well completion and groundwater sample collection
ranges from 24 hours (US Navy, 2007) to 48 hours (SC DHEC, 2005) to several ...
...2008.]
6.2.2 Temporary Monitoring Wells
Temporary groundwater monitoring wells or sampling points are generally installed
in boreholes driven by direct push ...
... according to the procedures outlined in Subsection 6.4.
The use of temporary groundwater monitoring wells is not as rigorous as the construction
and development of permanent groundwater ...
...monitoring wells is not as rigorous as the construction
and development of permanent groundwater monitoring wells, and the samples collected
may not be representative of the aquifer. However, ...
...a lower cost alternative to the initial characterization or delineation
of potential groundwater impacts.
While the use of temporary monitoring wells may be advantageous in some instances,
...
...may be advantageous in some instances,
they are not suitable for long-term monitoring of groundwater or for final decision
making purposes. The intended use of data collected from temporary monitoring ...
...with the HEER Office.
6.2.3 Other Wells
Other wells used for groundwater sampling include micro wells, existing production
wells and potable wells. The following sections ...
...Well Sampling
Collection of water samples for analysis from wells other than groundwater monitoring
wells should be approved by the HEER Office. The request should be accompanied by
...
...and depth, seal material and depth
Elevation of screen interval
Depth to groundwater table and bottom of unconfined aquifer
Depth to top and bottom of confined aquifer(s)
...
... (before any treatment). Purge the well long enough to obtain a representative sample
of groundwater with a minimal residence time in the collection/distribution system.
The purge volume may be ...
...Permanent Downhole Equipment
Dedicated sampling equipment that will reside within a groundwater monitoring well
must not alter the chemistry of the groundwater and must be resistant to chemical
...
...monitoring well
must not alter the chemistry of the groundwater and must be resistant to chemical
or physical deterioration. Inspect the equipment periodically ...
...Wells at Sites with DNAPL Plumes
Most DNAPLs that are commonly found in soil and groundwater contamination fall into
four groups (USEPA, 2004c):
Chlorinated solvents used ...
...manufactured gas plants (MGP)
The tendency of DNAPLs to move independently of groundwater flow makes it difficult
to delineate and remediate free phase DNAPL plumes. Most DNAPLs are ...
...DNAPLs with a high enough density, therefore, migrate vertically rather than
following groundwater movement. In addition, they may migrate according to the slope
of the uppermost confining unit, ...
...to the slope
of the uppermost confining unit, which may differ from the regional groundwater
flow direction. The migration of DNAPLs with a density (specific gravity) closer
to ...
...migration of DNAPLs with a density (specific gravity) closer
to 1 will be influenced by groundwater movement to a greater degree.
The USEPA has published a guidance document that helps ...
...PCBs are not volatile and are not sufficiently soluble to be readily detectable
in groundwater. The lighter end PCBs do have some solubility [3 milligram per liter
(mg/L) range] and ...
...polynuclear aromatics are volatile and sufficiently soluble to be detected
as a groundwater plume
Coal tar creosote mixtures are very diverse and may or may not be associated with
...
... Coal tar creosote mixtures are very diverse and may or may not be associated with
groundwater plumes. They may contain several chemicals that fluoresce
The HEER Office requires ...
...that both the free phase and dissolved plumes are delineated
at DNAPL sites. Borings and groundwater monitoring wells should be designed to accommodate
the selected investigation techniques.
...
...has many consequences. For example,
in a hydraulically isotropic, porous formation, the groundwater flow direction is
perpendicular to the equipotential lines of the water table or potentiometric ...
...is to prevent surface water from infiltrating into
the subsurface and to prevent vertical groundwater movement within the aquifer (HDLNR, 2004). By eliminating water movement vertically
within ...
...to be a potential conduit for
contaminant dispersion (USEPA, 1991a).
A groundwater monitoring well that is no longer needed, sustains damage serious
enough to potentially affect ...
...Office.
6.2.5.1 Well Abandonment Planning
All soil borings and groundwater monitoring wells will eventually require decommissioning
and closure in accordance with the ...
...depth.
Pressure grout the borehole to within 5 feet of ground surface or to above the groundwater
table, whichever is shallower (CalEPA, 1995b). Pressure
grouting is described ...
...well casing.
Pressure grout the well to within 5 feet of ground surface or to above the groundwater
table whichever is shallower (CalEPA, 1995b). Pressure
grouting is described ...
...Backfill with Clean
Soil
This option may be used only in areas where groundwater is not a current or potential
source of drinking water or where contamination has not been ...
...depth
Backfill the borehole to within 5 feet of ground surface or to above the groundwater
table whichever is shallower
The backfill must be composed of silty clay or clayey ...
...It is not recommended to use
neat cement in the saturated zone, particularly if the groundwater is acidic. Water
with an acidic pH may corrode the cement (USEPA, 1991a).
The rationale ...
... when abandoning wells in locations where load-bearing is not a concern and where
groundwater is encountered at a depth of less than 20 feet below ground surface.
6.2.5.5 Well ...
6.3 Groundwater Gauging
... '
6.3 GROUNDWATER GAUGING
The purpose of groundwater gauging is to construct a groundwater table map or ...
...GAUGING
The purpose of groundwater gauging is to construct a groundwater table map or a
potentiometric surface map for the site ...
...gauging is to construct a groundwater table map or a
potentiometric surface map for the site under investigation. The data are used ...
...The data are used to
calculate the hydraulic gradient(s) and the horizontal groundwater flow direction(s)
across the site. Therefore, all measurements must be taken within a 24-hour ...
... the contaminants present.
The HEER Office requires a minimum of two rounds of groundwater gauging to verify
the groundwater gradient(s) and flow direction(s). The two gauging events ...
...gauging to verify
the groundwater gradient(s) and flow direction(s). The two gauging events must be
separated by a minimum of ...
... On sites that are tidally influenced, perform a tidal study to determine the net
groundwater flow direction. If site investigation, monitoring and remedial efforts
continue over a year, ...
...investigation, monitoring and remedial efforts
continue over a year, include seasonal groundwater gauging into the investigation
to determine the influence of seasonal variations in the aquifer.
...
...determine the influence of seasonal variations in the aquifer.
Correct the measured groundwater elevations for tidal influences, barometric influences,
and overlying free product thickness.
...
... 6.3.1 Monitoring Well Equilibration
During well development, a large amount of groundwater is pulled through the surrounding
formation as well as the filter pack and the well casing. ...
...casing. This may disturb the chemical
equilibrium of the surrounding formation with the groundwater. In addition, the
filter pack may not reach chemical equilibrium with the aquifer.
...
... down the aquifer adjacent to the well.
The HEER Office recommends that groundwater gauging and sampling be conducted no
sooner than 14 days after well development. However, equilibration ...
...for several
minutes to document that the water level has equilibrated.
If groundwater sampling is to be completed on the same day, measure the depth to
water prior to sampling.
...
...measurement at least once to
confirm the measurement (USEPA, 1999a).
If groundwater sampling is to be completed on the same day, measure the total well
depth after sampling has ...
...
6.3.5 Well Gauging Log
At a minimum record the following information on groundwater monitoring logs:
Date
Project name and location
Field personnel
...
... Time of measurement
Depth to free product
Depth to groundwater
Depth to bottom of well
Observations (casing condition, well head ...
... etc.)
Activities that may influence water level (groundwater pumping, irrigation, etc.)
Decontamination procedures
...
...Tidal sea level changes
result in changes of hydraulic pressure at the shoreline, where groundwater flows
into the ocean. As the tide rises, hydraulic pressure increases and causes backpressure
...
...study may be necessary at sites that are tidally influenced.
Continually gauge and record groundwater elevations at the site for a minimum period
of 72 hours. Gauge at least three monitoring wells ...
...less. Synchronize data logging between all
pressure gauges.
Calculate the groundwater gradient and flow direction for each sampling time. Calculate
the net groundwater gradient ...
...gradient and flow direction for each sampling time. Calculate
the net groundwater gradient and net flow direction.
Compare the times of tidal fluctuations between the ...
...the ocean and each monitoring well
to determine the tidal lag of each well. Compare the groundwater elevation changes
within each well to the sea level changes to calculate the tidal efficiency ...
... within each well to the sea level changes to calculate the tidal efficiency (percent
of groundwater elevation change compared to sea level change).
On a map, present the groundwater flow ...
...elevation change compared to sea level change).
On a map, present the groundwater flow directions as they change throughout one
tidal cycle. Present the groundwater gradient ...
...flow directions as they change throughout one
tidal cycle. Present the groundwater gradient for each flow direction. In addition,
present the net groundwater flow direction and ...
...gradient for each flow direction. In addition,
present the net groundwater flow direction and gradient on the same map. If variations
are seen between tidal cycles, present ...
...cycle on a map.
6.3.6.2 Gauging at Tidally Influenced Sites
Groundwater gauging at tidally influenced sites requires careful planning. Choose
the date and time of ...
...every half
an hour between gauging other wells.
Assume that the change in groundwater elevation within the reference well is linear
throughout the half hour between measurements. ...
... throughout the half hour between measurements. Use the linear regression of the
groundwater elevation change in the reference well to correct the groundwater elevations
for all wells ...
...elevation change in the reference well to correct the groundwater elevations
for all wells for tidal influence. On sites with large variations in tidal efficiency
...
... choose more than one reference well.
6.3.7 Seasonal Effects
Groundwater flow may exhibit significant seasonal variations between the dry season
and the wet season ...
... and the wet season in Hawai`i. Characterizing seasonal and temporal variations
in groundwater flow is important at sites where the groundwater flow direction may
change due to seasonal ...
...flow is important at sites where the groundwater flow direction may
change due to seasonal variations. It is also important for site investigations
...
...and seasonal variations, the following processes can introduce
temporal variations in the groundwater table/potentiometric surface and possibly
in the groundwater flow direction (USEPA, 1992d; ...
...table/potentiometric surface and possibly
in the groundwater flow direction (USEPA, 1992d; CalEPA, 1995a):
Barometric effects
Variations ...
...
Identify and evaluate factors that result in short- or long-term variations in groundwater
elevations and flow patterns. Measure the water levels frequently enough to detect
...
...the water levels frequently enough to detect
and characterize temporal variations in groundwater flow.
6.3.9 Determination of Vertical Hydraulic Gradient and Flow Direction
...
... Determine the vertical hydraulic gradient and flow direction on sites where vertical
groundwater flow is significant. A deep vertical extent of a dissolved contaminant
plume is an indication ...
...A deep vertical extent of a dissolved contaminant
plume is an indication that vertical groundwater flow is significant.
To determine the vertical component of groundwater flow, install ...
...flow is significant.
To determine the vertical component of groundwater flow, install multiple piezometers
or wells in clusters or nests, or multi-level wells or sampling ...
...horizontally,
may produce imprecise information regarding the vertical component of groundwater
flow
Installation of multiple piezometers closely spaced or within ...
...document entitled "Handbook of Suggested
Practices for the Design and Installation of Groundwater-Monitoring Wells" (USEPA,
1991a) for a discussion of the advantages and disadvantages of ...
...on site.
The two or more measurement points must be aligned parallel to the horizontal groundwater
flow direction. During groundwater gauging in the piezometers, follow the procedures
...
... flow direction. During groundwater gauging in the piezometers, follow the procedures
for groundwater gauging detailed in Section ...
...gauging in the piezometers, follow the procedures
for groundwater gauging detailed in Section 6.3.
Calculate the vertical groundwater flow directions and ...
...gauging detailed in Section 6.3.
Calculate the vertical groundwater flow directions and hydraulic gradient using
the water level measurements. Generate a vertical ...
6.4 Purging
... '
6.4 PURGING
The purpose of well purging before groundwater sampling is to ensure that the samples
will be representative of the groundwater and contaminant ...
...sampling is to ensure that the samples
will be representative of the groundwater and contaminant levels in the vicinity
of the well. If a well is left untended for prolonged ...
...through
gas exchange with headspace, etc. Excessive purging may result in biased groundwater
samples, since it may dilute or increase the contaminant concentrations at the sampling
...
...a purging device that will not alter the geochemical and physical parameters
of the groundwater and dissolved contaminants or increase turbidity. Keep the contaminant
characteristics in mind ...
...though due to the greater potential to alter geochemical and physical
parameters of groundwater and other limitations, their use is generally limited
to monitoring wells with specific characteristics ...
...water above the screen has been purged. It also
ensures that during sampling, the groundwater has the shortest riser length to pass
(USEPA, 2002b).
If the intake is placed ...
...if a low-flow
purging and sampling technique is used (USEPA, 2002b).
All groundwater extracted from wells during purging must be properly containerized,
staged, sampled, and disposed. ...
...plastic sheet to ensure that the ground around
the well is not cross contaminated by groundwater, and to ensure that downhole equipment
does not transfer surface materials into the well.
...
...purging and sampling approach be utilized whenever feasible to collect
representative groundwater samples.
The purpose of the low-flow purging is to sample a specific depth within a well
...
... per liter.
Well water is clear to the unaided eye in areas where the local groundwater is known
to be clear and the turbidity readings are below 10 NTUs.
Turbidity ...
...±10 percent at concentrations larger than
10 NTU. In areas of known turbid groundwater, the final well water may be turbid
to the eye.
The HEER Office recommends ...
...
The HEER Office recommends the use of flow-through cells when monitoring groundwater
stabilization parameters during purging. Flow-through cells contain an inlet at
the ...
... liters per minute (USEPA, 2002b).
Alternatively, use a bailer to remove groundwater from the well. Start bailing near
the water table and keep lowering the bailer as purging continues. ...
... to determine water quality parameters during purging. Figure 6-11 presents an example
Groundwater Sampling Log containing locations for recording purging parameters prior
to the collection ...
...Log containing locations for recording purging parameters prior
to the collection of groundwater samples.
Figure 6-11. Example Groundwater Sampling ...
...samples.
Figure 6-11. Example Groundwater Sampling Log
[Source: US Navy, 2007]
...
6.5 Groundwater Sample Collection Methods
... '
6.5 GROUNDWATER SAMPLE COLLECTION METHODS
The purpose of groundwater sampling is to collect samples representative ...
...SAMPLE COLLECTION METHODS
The purpose of groundwater sampling is to collect samples representative for the
aquifer at the well location. Consider ...
...of the contaminant(s)
such as volatility, solubility, density (denser or lighter than groundwater) and
their resultant fate in the subsurface (adhesion to soil particles, biodegradation
...
...of the sampling approach.
The following sections describe different methods of groundwater sampling, the different
types of equipment for each method, and details on the appropriate ...
...6-2 presents the potential for representative analytical
results for commonly utilized groundwater sampling methods for common contaminants
of potential concern.
Table 6-2
...
... Table 6-2 Potential for Representative Analytical Results
for Commonly Utilized Groundwater Sampling Methods for Common Contaminants of Potential
Concern
...
... Figure 6-14. Field Setup for Purging and Sampling Well
Purging and sampling of groundwater monitoring well using a portable low-flow bladder
pump driven by a portable air compressor ...
...
Figure 6-15. Bailers for Purging and Groundwater Sampling
The following representative bailers are shown:
...
...Low-Flow Sampling
The purpose of low-flow sampling is to collect representative groundwater samples
for a specific depth within a well screen interval. The method is based on the assumption
...
...sampling approach be utilized where appropriate and feasible to collect
representative groundwater samples.
Low-flow sampling is preceded by low-flow purging (see Subsection
...
...between purging and sampling. Keep the pump rate
throughout sampling low enough that the groundwater flow exiting from the discharge
tube is laminar and does not induce turbulence in sampling ...
...the site contaminants.
Install a device that will prevent backflow to the pump to avoid groundwater contamination.
Install the pump at a sufficient height above the bottom of the well to ...
... 6.4.3 Purging Low-Permeability Formations.
Keep the pump rate low enough that the groundwater flow from the tube is laminar
and does not induce turbulence in sampling containers. Choose ...
... tasks.
The purpose of bailer sampling is to collect samples representative of the groundwater
at the sampling point. Therefore, bailer sampling must be preceded by well purging.
...
...creating a vacuum in an intake
line drawing from the monitoring well. The vacuum draws groundwater up to the pump,
where the water is dispensed from the end of the tubing. Tubing used for peristaltic
...
... Office prior to field investigation.
6.5.6 Others
Other groundwater samplers include passive diffusion samplers for VOCs or SVOCs,
HydraSleeve®, the syringe ...
...should be discussed with
the HEER Office before use.
6.5.7 Order of Groundwater Sampling
Collect samples in groundwater monitoring wells no sooner than 14 days after ...
...Sampling
Collect samples in groundwater monitoring wells no sooner than 14 days after well
development. This delay applies to newly ...
6.6 Filtration of Groundwater Samples
... '
6.6 FILTRATION OF GROUNDWATER SAMPLES
Figure 6-17. In-line 0.45 Micron Filter
...
...Micron Filter
This filter type is typically used in the field collecting a filtered groundwater
sample. An arrow on the body of the filter indicates the water flow direction when
...
...is important to avoid introducing turbidity into
the water samples since the HEER Office groundwater EALs are intended for comparison
to dissolved phase contaminants (and not contaminants adsorbed ...
... for sites near or adjoining the shoreline or in caprock substrate) filtering of
groundwater samples prior to analysis for metals is generally accepted, and filtering
for organic contaminants ...
... of the dissolved metal is dependent on the oxidation-reduction potential of the
groundwater. In-situ groundwater is often under-saturated relative to the oxygen
concentration in air. ...
...In-situ groundwater is often under-saturated relative to the oxygen
concentration in air. Therefore, oxygen can ...
...relative to the oxygen
concentration in air. Therefore, oxygen can dissolve from air into groundwater,
resulting in an increased oxidation-reduction potential, which may change the oxidation
...
...metals and result in metal precipitation. It is therefore important
to avoid aeration of groundwater collected for metals analysis.
Aeration may occur during collection or transport. To ...
... results in a pH lower than 2, which keeps the dissolved metals in solution.
A groundwater sample that is not filtered prior to preservation may yield false,
elevated levels of dissolved-phase ...
...the laboratory.
Due to the potential phase changes of metals that may occur during groundwater sampling
and filtration, the HEER Office may require that analytical data for filtered samples
...
...filtered samples
be accompanied by data for unfiltered samples, especially at sites where groundwater
is used as a water supply or may discharge into a nearby surface water body.
...
...150 to 200 milliliters
of sample to allow the filter to chemically equilibrate with the groundwater. Preserve
the sample immediately upon filtration using proper preservation methods, in the
...
6.7 Aquifer Data Collection Methods
...determination of key characteristics
used for evaluation of contaminant transport through groundwater. Hydraulic conductivity
is a measure of the formation's ability to transmit water. It is therefore ...
... a certain change in hydraulic head. Hydraulic head is most commonly represented
by groundwater elevation.
Permeability of soil/rock samples can be determined in the laboratory and ...
...conductivity
are slug tests and pumping tests. Both tests require access to one or more groundwater
monitoring well(s) on site. Ensure that the wells are properly developed and in
equilibrium ...
...commencing aquifer tests.
On sites that are tidally influenced or show temporal groundwater fluctuations,
monitor groundwater fluctuations in background wells throughout the duration ...
...fluctuations,
monitor groundwater fluctuations in background wells throughout the duration of
the aquifer test. The background ...
...may also be required at sites
with stratified aquifers or those sites where vertical groundwater movement is significant.
The guidance presented below is adequate for porous formations. ...
... hydraulic conductivity in fractured rock requires a different approach, since the
groundwater flow may be turbulent.
The slug test assumes that the aquifer is confined. For pumping ...
...of known volume (referred to as a "slug") from a well
and continuously monitoring the groundwater level while the well recovers to its
original level (Freeze et. al., 1979). Addition or
...
...The change in hydraulic head is monitored, usually
in terms of drawdown, or change in groundwater elevation in the aquifer in response
to pumping and removal of water from the formation. The ...
...is withdrawn from confined aquifers, the aquifer does not undergo dewatering,
unless the groundwater elevation/head is lowered below the confining layer. The
water is released from storage through ...
6.8 Groundwater Modeling
... '
6.8 GROUNDWATER MODELING
The purpose of groundwater modeling is to generate a visual representation of ...
...MODELING
The purpose of groundwater modeling is to generate a visual representation of an
aquifer including the overall groundwater ...
...modeling is to generate a visual representation of an
aquifer including the overall groundwater movement, and in the case of contaminated
sites, the fate and transport of contaminants. Groundwater ...
...movement, and in the case of contaminated
sites, the fate and transport of contaminants. Groundwater modeling is also used
to predict contaminant plume movement into the future or to predict the ...
...or to predict the aquifer
and plume response to remedial activities.
Groundwater modeling may be done manually by using a calculator or spreadsheet and
then creating a graphical ...
...spreadsheet and
then creating a graphical depiction of the data using flow nets. Manual groundwater
modeling methods may be useful for creating preliminary site conceptual models intended
...
...and the initial contaminant plume extent.
However, if the purpose of groundwater modeling is to predict how a contaminant
plume changes over time or how it will respond to ...
...tool in the design of sampling strategies
during site monitoring and in the design of groundwater remediation systems. Computer
groundwater models are based on the geologic and hydrologic field ...
...remediation systems. Computer
groundwater models are based on the geologic and hydrologic field data collected
during drilling, geotechnical ...
... 6.8.1 Gradient and Flow Direction Determination
The simplest way to determine the groundwater gradient and flow direction is by
graphically constructing a flow net for the site. A flow ...
...lines
connect points of equal head and the flow lines depict the interpreted groundwater
flow path or flow direction.
To construct a flow net for a site, measure the ...
...a flow net for a site, measure the hydraulic head in wells across the
site following the groundwater gauging procedures detailed previously in this section.
Enter the measurements onto a site ...
...above mean sea level or other datum plane.
Add flow lines to depict the movement of groundwater at the site. Groundwater follows
the path of steepest groundwater gradient. At a site where ...
...at the site. Groundwater follows
the path of steepest groundwater gradient. At a site where the aquifer formation
...
...follows
the path of steepest groundwater gradient. At a site where the aquifer formation
is isotropic and porous, the steepest groundwater ...
...gradient. At a site where the aquifer formation
is isotropic and porous, the steepest groundwater gradient is the shortest path
between equipotential lines. The shortest path is perpendicular ...
...lines such that the flow is equally divided between adjacent lines.
Calculate the groundwater gradient as follows: Measure the distance between two
equipotential lines along a flow line, ...
... loss between the equipotential lines. Divide the head loss by the distance.
The groundwater flow direction is along the flow lines. Depict flow lines as arrows
pointing in the direction ...
...is along the flow lines. Depict flow lines as arrows
pointing in the direction of groundwater flow, i.e., in the direction of declining
hydraulic head.
6.8.2 Velocity, ...
...listed in Subsection 6.7, Aquifer Data
Collection Methods.
Calculate the groundwater velocity (v) using the following equation:
v = q/ne = (K dh/dl) / ne
...
... v = q/ne = (K dh/dl) / ne
Where:
v = actual groundwater velocity
q = Darcy velocity
ne = effective porosity (connected ...
...Darcy velocity
ne = effective porosity (connected pore space through which groundwater can flow)
K = Hydraulic conductivity
dh/dl = groundwater ...
...can flow)
K = Hydraulic conductivity
dh/dl = groundwater gradient (change in groundwater elevation in two wells over
distance between the wells)
...
...gradient (change in groundwater elevation in two wells over
distance between the wells)
Compare the ...
...wells over
distance between the wells)
Compare the calculated groundwater velocity to the velocity range expected based
on aquifer lithology.
Note that ...
...has many consequences.
For example, in a hydraulically isotropic, porous formation, the groundwater flow
direction is perpendicular to the equipotential lines of the water table/potentiometric
...
...may be used at a site for many different goals including: (1) estimating
how the actual groundwater system functions; (2) selecting sampling approaches,
objectives and locations; (3) predicting ...
...are relatively more simplistic, offer an inexpensive method to conduct
preliminary groundwater analysis, and may be useful during the early phases of a
project. Numerical approaches are ...
...knowledge and software. However, numerical approaches easily deal with variability
in the groundwater flow and contaminant transport parameters, which provides flexibility
in representing complex ...
...remedial solutions and for the evaluation
of environmental hazards.
A groundwater modeling report should, at a minimum, include (USEPA,
1992a):
Previous studies
...
6.9 Surface Water Sample Collection Methods
...Filtration
For surface water filtration follow the same procedures outlined for groundwater
filtration of groundwater samples (Subsection 6.6, Filtration).
...
... filtration of groundwater samples (Subsection 6.6, Filtration).
...
7.0 Soil Vapor and Indoor Air Sampling Guidance
...risks posed to outdoor
air and overlying buildings. The development of HDOH soil, groundwater and soil
gas (�vapors�) action levels for evaluation of vapor intrusion hazards is described
...
...the document Evaluation of Environmental Hazards at Sites with Contaminated Soil
and Groundwater (�EHE guidance;� HDOH 2016,
see also HDOH, 2016b.). The discussion provided below
...
7.1 Soil Vapor Transport Mechanisms and Conceptual Models
...storage tanks.
The emission 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
...
...(see HDOH 2016). Vapors in vadose-zone soil could also
migrate downwards and impact groundwater that has otherwise not been directly affected
by the release. This has been recognized, for ...
...associated with
the presence of relatively shallow, free product in vadose-zone soil or groundwater
(see USEPA 2013). Under most site scenarios, the breakdown
of petroleum compounds ...
...lead to potential vapor intrusion concerns
even in the absence of free product in soil or groundwater. Dilute plumes of solvent-contaminated
groundwater have, for example, been documented to travel ...
...Dilute plumes of solvent-contaminated
groundwater have, for example, been documented to travel thousands of feet downgradient
of initial release ...
...during an earlier
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.
...
...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.
...
7.2 Soil Vapor Intrusion to Indoor Air
...soil of equal magnitude, especially in the case of petroleum releases
that have reached groundwater. As the water table falls and exposes this smear zone,
an increase in vapor emissions can occur. ...
...on the expected subsurface geology,
depth to the potential source contaminants or groundwater, and actual or potential
human or environmental receptors, as well as other specific information ...
...transport includes the outward diffusion
of vapor-phase chemicals from impacted soil or groundwater and the potential advective
flow of the vapors into an overlying building (Figure 7 1).
...
...observed with petroleum
hydrocarbon or volatile organic compounds (VOC) impacted soil and groundwater (Figure 7-2). The biodegradation processes include
aerobic and anaerobic degradation of contaminants ...
7.3 Characterization, Delineation and Monitoring
...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 ...
7.4 Soil Vapor Probe Installation
...air samples are collected following the discovery
or identification of subsurface soil or groundwater contamination containing volatile
or semi-volatile constituents. In addition to the evaluation ...
...be carried out in a manner that minimizes stripping of VOCs from free product
in soil or groundwater or stripping of VOCs otherwise sorbed to soil particles or
dissolved in groundwater and not ...
...or stripping of VOCs otherwise sorbed to soil particles or
dissolved in groundwater and not initially present in the vapor phase. This is accomplished
primarily by minimizing ...
...additional stripping of VOCs in product,
sorbed to soil particles or dissolved in groundwater.
HDOH is currently studying approaches for the collection of representative and ...
7.6 Soil Vapor Sample Collection Procedures
...samples are collected to help locate and characterize areas
of contaminated soil and groundwater that might require remediation or long-term
management. The direct collection of groundwater ...
...that might require remediation or long-term
management. The direct collection of groundwater samples is generally adequate to
identify contamination with volatile chemicals. This is because ...
...contamination tends
to become dispersed over relatively large areas due to diffusion and groundwater
flow. The additional collection of soil vapor samples to assist in the identification
...
...collection of soil vapor samples to assist in the identification
of areas of contaminated groundwater is typically not necessary or required.
Note, however, that groundwater action ...
...is typically not necessary or required.
Note, however, that groundwater action levels presented in the HDOH EHE guidance
are not applicable for sites where the depth ...
...levels presented in the HDOH EHE guidance
are not applicable for sites where the depth to groundwater is less than ten feet
due to limitations in the models and data used to develop the levels. ...
...also be considered. Direct collection of soil vapor samples regardless of soil
and/or groundwater data is also recommended for sites with a very high potential
for the release of volatile chemicals. ...
...stations and dry cleaners
(see Section 7.6.2.2).
As is the case for groundwater, volatile chemicals in subsurface soils tend to more
evenly disperse over relatively large ...
...approach
for the initial evaluation of vapor intrusion hazards at sites where soil or groundwater
is contaminated with volatile chemicals (HDOH 2016):
...
...
Contaminants in Vadose Zone 2Soil and/or 3Groundwater Pose
Potential Vapor Intrusion Hazards
...
...suspected (e.g., PCE vapors under a dry cleaner).
Free product on
groundwater table or dissolved VOC concentrations above Tier 1 groundwater action
levels for vapor ...
...table or dissolved VOC concentrations above Tier 1 groundwater action
levels for vapor intrusion.
VOC concentrations
...
...intrusion.
VOC concentrations
below Tier 1 EALs for both soil or groundwater and significant volume (e.g.,
>10m3) of VOC-contaminated soil or other potential ...
... vapors under a building slab not suspected.
Compare groundwater
and soil analytical data to appropriate HDOH environmental action levels (EALs)
...
...in Evaluation of Environmental Hazards at Sites with Contaminated Soil
and Groundwater (HDOH 2016) or site-specific
action levels approved by HDOH. See Table C-1a for Groundwater ...
...(HDOH 2016) or site-specific
action levels approved by HDOH. See Table C-1a for Groundwater Action Levels and
Table C-1b for Soil Action Levels, located in Appendix 1 of the EHE document; ...
...results to Shallow Soil Gas Action Levels for
areas over or near a plume where Groundwater and/or Soil EALs for vapor intrusion
are approached or exceeded or sites where a potentially ...
...vapor sampling is recommended (Step 2) based on the occurrence of VOCs
in soil and/or groundwater and the distance between the building and the source
area.
The initial ...
...soil; see Appendix
1 in HEER EHE guidance, HDOH 2016). Thin lenses of
perched groundwater can further reduce upward vapor flux. Aerobic biodegradation
of non-chlorinated, vapor-phase, ...
...within a few feet of a source area (e.g.,
heavily contaminated soil or free product on groundwater).
A discussion of targeted chemicals of concern for petroleum releases is provided
...
...mass or concentration of petroleum in underlying soil or the presence of free
product on groundwater (e.g., Abreu et. al 2009, McHugh 2010; USEPA 2013).
For dissolved-phase contaminants a �vertical ...
... is at a depth of greater than fifteen feet year round and no free product is present
on groundwater and contaminated soil is not present in the vadose zone, then
potential vapor intrusion hazards ...
...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
...
...Large volumes of shallow, contaminated soil or widespread free
product on shallow groundwater (i.e., <30ft deep) could lead to the accumulation
of vapors under caps and a progressive ...
...overlie
deep (i.e., >30ft) widespread, heavily contaminated soil or free product on groundwater.
Such scenarios could be possible with large releases from fuel pipelines, fuel hydrant
...
...provided in the HEER guidance Long-Term Management of Petroleum-Contaminated Soil
and Groundwater HDOH 2007c).
7.6.2 Soil Vapor Sampling Design
...
...vapor sampling strategy depends on site-specific conditions, including soil
types and groundwater levels, the number and size of existing buildings, and current
site use or future development ...
...of the source area because soil vapor can migrate in a different
direction than groundwater flow. When assessing upward, vertical migration, vapor
samples from multiple depths may be ...
... Figure 7-4: Schematic of Soil Vapor Concentration Profile. VOCs volatilize
out of a groundwater plume and diffuse vertically toward the surface. Vapor phase
concentrations are highest ...
...diffuse vertically toward the surface. Vapor phase
concentrations are highest at the groundwater-vadose zone interface and decrease
with decreasing depth. Vapors can accumulate under buildings ...
...likely might not mimic the shape of the primary
source area (i.e., contaminated soil or groundwater). This is because the outward,
lateral migration of vapors away from the source area is strongly ...
...a depth of five to ten feet below ground surface (or no more than two to three
feet above groundwater for shallow water tables) in order to take into consideration
the potential buildup of vapors ...
...periods of time in the vadose zone
following active, in situ remediation of contaminated groundwater (�residual
vapor plume,� see Table 7-1). The San Diego County
Site Assessment and ...
...as the nature and magnitude of the release,
the subsurface geology and the depth to groundwater. The investigation of potential
vapor intrusion hazards will require the placement of sample ...
...of ten feet for petroleum-contaminated sites or no more than
two to three feet above groundwater for sites with a shallow water table. This is
necessary in order to take into consideration ...
...site conditions. Note
that the same is true with respect to the representativeness of a groundwater sample
collected from a five-foot, monitoring well screen or from a much smaller interval
...
7.7 Indoor Air Sample Collection Procedures
...potential vapors is present below the
building (e.g., petroleum free product on shallow groundwater) then the collection
of source area soil vapor samples is also recommended (see
...
7.8 Soil Vapor or Indoor Air Sample Analysis
...of soil vapor or indoor air samples can be more involved and complex
than soil or groundwater sample collection. This is due in part to the need for
special sampling equipment and containers ...
...of these approaches is provided
in Table 7-3.
Similar to soil and groundwater sample collection, a combination of sampling approaches
can be used if analyzing for a broad ...
...environment
(e.g., to evaluate TPH in vapors associated with diesel-contaminated soil or groundwater)
and the volume of vapors to be drawn is less than one liter then the concurrent
collection ...
...to the PDS sample after collection
should be considered in the similar manner as done for groundwater samples (see
Section 6). The water is then analyzed for targeted VOCs,
with results ...
7.9 Gas Phase Sample Evaluation
...
7.9.2 Permanent Probes
Permanent probes are constructed similar to groundwater monitoring wells installed
using auger or direct push drilling techniques. However, permanent ...
7.10 Documentation of Soil Vapor or Indoor Air Sampling
...seasonal weather variations and associated
water table fluctuations and tidal effects on groundwater elevation. Multiple sampling
events are recommended if the conceptual model identifies the ...
...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
...
...
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 ...
...A minimum
of one round of samples should be collected at chlorinated solvent sites where groundwater
action levels are approached or exceeded or a significant source is present in the
...
...1) Sites with widespread,
heavy contamination in vadose-zone soil and/or floating on groundwater within 30
vertical feet or 100 lateral feet of a building slab that do not meet the above-noted
...
7.0 Soil Vapor and Indoor Air Sampling Guidance
...document Screening for Environmental Hazards
at Sites with Contaminated Soil and Groundwater (Environmental Hazard Evaluation
[EHE] guidance [HDOH 2016]). In the EHE guidance,
...
9.1 Pesticide Contamination at Former Agricultural Facilities and Sites
...contamination could also pose leaching hazards
and subsequent contamination of underlying groundwater resources (e.g., triazine
pesticides and fumigants). This generally requires that the full ...
...from four to fourteen inches below ground surface.
DBCP and EDB have been detected in groundwater wells on Oahu and Maui and have not
been used since the mid-1980s (HDOH 1985,
...
...(TCP) is an impurity associated with D-D
and has also been detected in groundwater wells in the state (see
HDOH 1985)
Fumigants are not likely to be ...
...direct-exposure concern, these chemicals can still pose leaching threats
to underlying groundwater. Comparison to screening levels that do not consider leaching
is therefore not appropriate ...
9.3 Petroleum Contaminated Sites
...category of Total Petroleum Hydrocarbons (TPH). The concentration
of TPH in soil and groundwater is typically reported in terms of "carbon ranges,"
or the number of carbon molecules in individual ...
...aliphatics (HDOH 2016, 2012).
Although not studied in detail, dissolved-phase gasoline in groundwater is also
likely to be biased towards more soluble, lighter-range compounds.
...
... releases of middle distillate fuels. Dissolved-phase, middle-distillate fuel in
groundwater could also be biased towards more soluble, "gasoline-range" compounds.
A dominance of "TPHg" ...
...also be biased towards more soluble, "gasoline-range" compounds.
A dominance of "TPHg" in groundwater samples does not in itself indicate that the
source of the contamination is associated with ...
...not practicable. This guidance, Long-Term
Management of Petroleum-Contaminated Soils and Groundwater (HDOH,
2007c) is included in TGM Section 19 as Appendix 19-A.
The document includes ...
...database is possible in scenarios where
the area and volume of contaminated soil and/or groundwater is minimal.
Table 9-5 Target Analytes for Releases of Petroleum Products
...
...and methane
Groundwater
Same as soil
...
...and methane
Groundwater
Same as soil
...
...and methane
Groundwater
same as soil
...
...Analytes
Recommended target analytes for petroleum contaminated soil and groundwater are
provided in Table 9-5.
Petroleum contamination in soil, water or air/soil ...
...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, ...
...warranted.
Silica gel cleanup of samples, in particular for surface water and groundwater,
should not be carried out without consultation with HDOH. Two options are recommended:
...
...for the sample. The polar compounds, which can dominate the overall
mass of TPH in groundwater at aged-release sites, are primarily organic acids/esters
and alcohols with variable amounts ...
...for comparison to data. In most cases, it is anticipated
that long-term management of groundwater contaminated primarily with polar, TPH
breakdown compounds above HDOH action levels will still ...
...(e.g., via impacts to drinking water resources).
Comparison of data for groundwater samples tested with and without silica gel cleanup
could be useful for assessing the state ...
...assessing the state of natural biodegradation within a plume
of petroleum-contaminated groundwater and optimizing remedial and monitoring actions.
For example, no further active remediation ...
10.3 Data Quality Assurance Procedures
...replicates (triplicates for MIS).
Groundwater duplicates
1 per day for every 10 samples
...
...as a Relative Standard Deviation
(RSD) percent:
Groundwater field duplicates are evaluated by determining a RPD for the replicates,
using RPD formula as ...
...In some
cases, additional care must be taken to evaluate comparability. For instance, groundwater
samples handled in the exact same fashion, collected within the same sampling event,
...
10.6 Field QA/QC
...or triplicate samples collected from within
the same decision unit or from the same groundwater well to evaluate the precision
of the sampling effort. Replicates are to be collected, preserved, ...
... 10.6.1.1 Discrete Sampling Replicates
In general, for discrete sampling of groundwater or soil the HEER Office recommends
collecting one replicate QA/QC sample per field day per ...
...and co-located sample data compared to ensure these
DQO are met.
Duplicate groundwater samples
For non-volatile groundwater contaminants collected in vials, generally two sample
...
...samples
For non-volatile groundwater contaminants collected in vials, generally two sample
containers are "alternately" filled. ...
...would be filled by going back and forth with the discharge tubing.
For volatile groundwater contaminants, where multiple 40 ml vials are commonly used
for each sample and loss of volatiles ...
Contents
...
Laboratory Methods, Containers, Preservation, and Holding Times for
Groundwater
Samples
...
11.0 HANDLING AND ANALYSIS OF SAMPLES
...analytical methods for each sampling event.
This section focuses on soil and groundwater samples collected as part of an environmental
investigation, which are sent to a fixed laboratory ...
...is presented on the use of soil sampling equipment in
Section 5 and on the use of groundwater or surface water sampling equipment
in Section 6. A discussion of gas phase samples is not
...
Appendices
...
Laboratory Methods, Containers, Preservation, and Holding
Times for Groundwater
Samples
...
11.1 SAMPLE CONTAINERS
... Table 11-B in the Appendix 11-B present the recommended sample containers
for groundwater. The sample volumes for the containers listed in the tables represent
the recommended size ...
...one sample container may be required
for the associated parameter and method. If soil or groundwater samples are to be
analyzed for multiple contaminants, the sample volumes listed in the tables ...
...Containers
The type of sample container used for collecting surface water or groundwater samples
is dependent upon the specific analysis to be performed. Other factors, such as
...
...in 1 liter
amber glass jars without the use of chemical preservatives. When collecting groundwater
samples, fill the water sample containers by directing the outlet of the sampling
...
...should be carefully placed
on the jars and sealed with zero headspace. When collecting groundwater samples
for volatile analysis, fill the 40 mL jars by directing the outlet of the sampling
...
11.2 SAMPLE PRESERVATION AND HOLD TIMES
...in the Appendices,
present the recommended preservation and hold times for soil and groundwater, respectively.
Sample preservation consists of methods to assure the samples analyzed ...
... chemical reagents from the analytical laboratory. Carefully place the soil or groundwater
samples into the sample containers to minimize loss of chemical preservative as
well ...
...the sample media. For example,
calcareous soil may react with sodium bisulfate; turbid groundwater collected from
a coral aquifer formation may react with hydrochloric acid. If the sample media
...
...
Some samples collected for specific analysis, such as dissolved metals in groundwater,
may require pre-treatment prior to collection, as well as preservation (see
...
11.3 SAMPLE CONTROL AND CHAIN-OF-CUSTODY PROCEDURES
...sample media in chain-of-custody
batches for submittal to the laboratory (i.e., submit groundwater samples on one
chain-of-custody batch separate from soil samples collected for the same project).
...
11.4 SAMPLE SHIPPING
...(i.e., no chemical preservatives added during
collection).
For groundwater samples specifically, very small quantities of certain dangerous
goods may be transported without ...
11.5 APPROVED ANALYTICAL METHODS
... 11-B in the Appendices provide the recommended analytical methods for soil
and groundwater analysis, respectively.
Use other EPA-approved methods (such as Methods for Chemical ...
Appendix 11-B Tables
... Laboratory Methods, Containers, Preservation, and Holding
Times for Groundwater Samples
...
Contents
... 13-4.
Summary of Action Levels Used to Select Tier 1 Soil and Groundwater
EALs for Benzene
...
...Hazard Identification
Page, Using
Benzene at Noted Concentration in Soil and Groundwater as an Example
13-5c.
...
...EAL Surfer EHE Summary Report, Using Benzene at Noted Concentration
in Soil and Groundwater as an Example
13-6.
...
...
13-7.
Environmental Hazard Map for Hypothetical Site with Groundwater Contamination
...
13.0 Environmental Hazard Evaluation
...document Screening for
Environmental Hazards at Sites with Contaminated Soil and Groundwater
(HDOH, 2016). Environmental Hazard Evaluation (EHE)
is the link between site investigation
...
...actions carried out to address hazards posed by the presence
of contaminated soil and groundwater, as shown in Figure 13-1.
Figure 13-1. Expanded ...
...or absence of potential
environmental hazards associated with contaminated soil and groundwater is determined
and summarized in an EHE (i.e., a review of potential environmental hazards), ...
... absence of a basic understanding of environmental hazards posed by contaminated
soil or groundwater run the risk of being incomplete, and require unanticipated,
additional field work. This can ...
... entitled Screening for Environmental Hazards at Sites with Contaminated Soil and
Groundwater (HDOH, 2016). Readers unfamiliar
with the concept of environmental
hazard evaluation ...
Figures
... 13-4.
Summary of Action Levels Used to Select Tier 1 Soil and Groundwater
EALs for Benzene
...
...Hazard Identification
Page, Using Benzene at Noted Concentration in Soil and Groundwater as an Example
13-5c.
...
...EAL Surfer EHE Summary Report, Using Benzene at Noted Concentration
in Soil and Groundwater as an Example
13-6.
...
...
13-7.
Environmental Hazard Map for Hypothetical Site with Groundwater Contamination
...
13.1 TARGET ENVIRONMENTAL HAZARDS
...
Contaminated Groundwater
...
...
Toxicity concerns related to contamination of groundwater that is a current or potential
source of drinking water
...
...
Emission of volatile contaminants from groundwater and intrusion into overlying
buildings
...
...
Discharges of contaminated groundwater and toxicity to aquatic organisms. Includes
contamination of fish and shellfish ...
...water (rainfall, irrigation,
etc.) and subsequent contamination of groundwater resources
...
...
Emission of volatile contaminants from soil or groundwater into overlying buildings
and/or outdoor air.
...
...Levels.
The four target media tested to evaluate these potential hazards are groundwater,
soil, soil gas and indoor air.
A summary ...
...or subsurface utility activities that require disturbance of
heavily contaminated soil or groundwater.
Leaching of contaminants from soil is also important to consider, even though ...
...this
is rarely included in traditional risk assessments. Discharges of contaminated groundwater
or free product into nearby surface water bodies, either naturally or via leakage
...
...pose significant environmental
hazards to aquatic habitats. When large plumes of impacted groundwater threaten
fisheries, the discharge of contaminated groundwater to surface water and subsequent
...
...threaten
fisheries, the discharge of contaminated groundwater to surface water and subsequent
uptake of contaminants into seafood may also be of concern. ...
...aquifers.
Potential vapor intrusion hazards will also usually be identified for groundwater
contaminated with carcinogenic, volatile chemicals. Chemicals that have a low taste
...
... drinking water standards. This can drive remedial actions if discharge of contaminated
groundwater into a sensitive aquatic habitat is possible. Free product could pose
both toxicity and gross ...
...attention at some sites, including
exposure of construction workers to contaminated groundwater and the potential uptake
of contaminants in garden produce. The need to include additional ...
13.2 DEVELOPMENT OF VAPOR INTRUSION SCREENING TOOLS
... Hazard Evaluation (EHE) guidance (HDOH 2016.). The
guidance also presents soil and groundwater action levels for screening of potential
vapor intrusion hazards. The collection of soil vapor ...
13.3 TIER 1 ENVIRONMENTAL ACTION LEVELS
...Action Levels (Tier 1 EALs) are concentrations of contaminants
in soil, soil gas and groundwater below which the contaminants are assumed to not
pose a significant threat to human health or ...
...document Screening for Environmental Hazards at Sites with Contaminated
Soil and Groundwater (HDOH, 2016). The EALs
described in the EHE document
are not intended to establish ...
...representation of site environmental
conditions with respect to contaminated soil and groundwater and related environmental
hazards (see Section 3.4.3). Four default CSMs
were used ...
...Four default CSMs
were used to develop The Tier 1 EALs (HDOH, 2016):
Groundwater affected or potentially
affected by the release is a current or potential drinking water ...
...drinking water resource; site
located within 150m of a surface water body.
Groundwater affected or potentially
affected by the release is a current or potential drinking water ...
...water resource; site
not located within 150m of a surface water body.
Groundwater affected or potentially
affected by the release is not a current or potential drinking ...
...drinking water resource;
site located within 150m of a surface water body.
Groundwater affected or potentially
affected by the release is not a current or potential drinking ...
...water body.
Only surface water bodies that are hydraulically connected to groundwater are considered
to be potentially threatened by contaminated groundwater. For the purposes of ...
...are considered
to be potentially threatened by contaminated groundwater. For the purposes of the
Tier 1 EALs, it is further assumed under each default CSM that contaminated ...
...HDOH document Evaluation of Environmental
Hazards at Sites with Contaminated Soil and Groundwater for additional information
on site conditions assumed for development of the Tier 1 EALs (HDOH,
...
...Tier 1 EAL [refer to lookup tables in HDOH EAL document (HDOH,
2016)].
For groundwater, the action level for drinking water toxicity concerns drives environmental
hazards and is ...
...
Figure 13-4. Summary of Action Levels Used to Select Tier 1 Soil and Groundwater
EALs for Benzene. CSM A based on (1) groundwater is a drinking water resource, and
...
... EALs for Benzene. CSM A based on (1) groundwater is a drinking water resource, and
(2) site within 150m of a surface water body. For ...
...water resource, and
(2) site within 150m of a surface water body. For soil and groundwater, the lowest
action level for environmental hazards is selected as the final Tier 1 ...
...Surfer, simply select the appropriate site scenario information from
the pull-down list (groundwater utility, distance to nearest surface water body,
land use, etc.), select the target contaminant, ...
...and (optional) input the representative
concentration of the contaminant in soil and/or groundwater. If included, the input
concentration is compared to action levels for specific environmental ...
... levels for leaching hazards are unchanged because land use does not alter the threat
to groundwater. Groundwater action levels for vapor intrusion hazards are also higher
for a commercial/industrial ...
...Groundwater action levels for vapor intrusion hazards are also higher
for a commercial/industrial land ...
...soil is located
within three meters of the ground surface ("shallow") and overlies groundwater that
is a current or potential source of drinking water. The site is within 150 meters
...
...are not flagged as potential hazards. The input concentration
of 150 ug/L benzene in groundwater flags drinking water toxicity concerns and aquatic
ecotoxicity concerns, but no other potential ...
...Data used for this example
was 5.1 mg/kg benzene in soil, and 150ug/L benzene in groundwater. Also, check for
updates. The EAL Surfer is updated periodically and the page configurations ...
...Hazard Identification
Page, Using Benzene at Noted Concentration in Soil and Groundwater as an Example.
Refer also to Figure13-5a.
...
...EAL Surfer EHE Summary Report, Using Benzene at
Noted Concentration in Soil and Groundwater as an Example. Refer also to Figure13-5a.
This page can be printed and included in ...
...is to determine the extent of investigation
needed at a site where contaminated soil or groundwater is identified. The list
of Chemicals of Potential Concern (COPCs) can be quickly narrowed down ...
...Potential Concern (COPCs) can be quickly narrowed down by direct
comparison of soil and groundwater data to the Tier 1 EALs (HDOH,
2016). Further
consideration of contaminants that ...
...3 and Section 9 ).
If the reported concentration of volatile contaminants in soil or groundwater exceed
action levels for vapor intrusion concerns, then soil gas data can be collected
...
...identification of potential
environmental hazards associated with contaminated soil and groundwater (refer to
Section 3.4). With the exception of gross contamination,
most of the environmental ...
...gas action levels in this guidance helps expedite
this evaluation. A detailed review of groundwater data can sometimes be used in
place of soil action levels to better evaluate leaching and groundwater ...
...data can sometimes be used in
place of soil action levels to better evaluate leaching and groundwater contamination
concerns. In other cases, additional laboratory tests and/or use of environmental
...
...action levels to understand the
specific environmental hazards posed by contaminated groundwater is especially important.
Identifying toxicity hazards and taste and odor hazards in groundwater ...
...is especially important.
Identifying toxicity hazards and taste and odor hazards in groundwater that is currently
used as a source of drinking water is obviously important. Expeditious actions ...
...soil are usually warranted.
In contrast, long-term monitoring may be acceptable for groundwater that poses only
gross contamination hazards (e.g., toxicity-based action levels for currently ...
...surface water.
Long-term management will be required for sites where soil and groundwater contaminated
above levels of potential concern cannot be remediated in a relatively short time
...
... acceptable alternatives) should be used to delineate areas of contaminated soil
and groundwater that will require long-term management as well as the specific environmental
hazards posed ...
...below commercial
laboratory Method Reporting Limits (MRLs) for a number of chemicals in groundwater.
This is not generally the case for soil. As discussed in the EHE guidance, the laboratory
...
...2016).
Chemicals with laboratory MRLs that could exceed the HDOH EALs for groundwater are
given in Table 13-2.
If the reported concentration of a chemical exceeds ...
...
Groundwater
...
13.4 CHEMICALS NOT LISTED IN LOOKUP TABLES
...'
13.4 CHEMICALS NOT LISTED IN LOOKUP TABLES
Soil, groundwater, soil gas and/or indoor air action levels should be developed
and approved by HDOH for chemicals ...
13.5 STEPS TO ENVIRONMENTAL HAZARD EVALUATION
...to begin to identify potential environmental hazards at a site as
soon as initial soil, groundwater and other data are received. As discussed above,
this is used to guide completion of the site ...
...to the HDOH Screening
for Environmental Hazards at Sites with Contaminated Soil and Groundwater
guidance document (HDOH, 2016).
The list of COPCs can be quickly narrowed ...
...(DU) and the
representative concentration of target COPCs within each DU determined. For groundwater
and soil gas samples, direct reference to reported concentrations of COPCs in single
...
...document Screening for Environmental Hazards at Sites
with Contaminated Soil and Groundwater ["EHE guidance" (HDOH,
2016)]. A summary of commonly used approaches is provided in ...
...a much lower vapor intrusion
hazard than predicted by simple comparison of soil or groundwater data to HEER Office
action levels. The additional data could negate the need for remedial actions ...
...can help identify
the presence of contamination that was not detected in earlier soil and groundwater
sample collection.
Preparing a traditional human health risk assessment ...
...focuses on toxicological risks
associated with direct exposure to contaminated soil, groundwater, or air. While
this is important, direct exposure is only one of several potential environmental
...
... Table 13-3 Commonly Used Approaches for Evaluating Environmental Hazards
in Groundwater
...
...
� Identification and monitoring of nearby, groundwater supply
wells and guard wells
...
...
� Long-term monitoring of groundwater to evaluate plume migration
potential
...
...
� Use of groundwater plume fate & transport models in combination
with long-term monitoring ...
...
� Use of groundwater data to evaluate plume expansion and migration
over time
...
...fate and transport models to predict long-term migration
potential of groundwater contaminant plumes
...
...
� Check groundwater for free product
� ...
...
� Collection of groundwater data
� ...
...spill area, not the
site as a whole, is the target where the "receptor" of concern is the groundwater
directly underneath the contaminated soil. If Tier 1 soil action levels for leaching
...
...carried out. Keep in mind that
soil data are not necessarily good indicators of potential groundwater contamination.
This is especially true for chlorinated solvents. Releases of wastewater contaminated
...
...of the solvent compounds, even though the release results
in significant contamination of groundwater.
Soil or groundwater data flagged for potential vapor intrusion almost always indicates
...
...
Soil or groundwater data flagged for potential vapor intrusion almost always indicates
that soil gas samples should ...
...soil gas samples should be collected 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 ...
...located in this area.
Documenting where grossly contaminated soil and groundwater will be left in place
at a site is also important (e.g., Figure 13-7). Gross contamination ...
...13-7). Gross contamination hazards often
drive the cleanup of contaminated soil and groundwater, not direct exposure or even
leaching hazards. Over time, grossly contaminated soil and groundwater ...
...not direct exposure or even
leaching hazards. Over time, grossly contaminated soil and groundwater can generate
methane and related explosive hazards. Although the contamination may not pose ...
...under current site conditions, the unexpected discovery of grossly contaminated
soil and groundwater during subsurface construction or utility activities can result
in significant delays and project ...
...
Figure 13-7. Environmental Hazard Map for Hypothetical Site with Groundwater
Contamination. Hypothetical site contaminated with petroleum. Areas delineated by
...
...vapor intrusion hazard so property can be
redeveloped. Aggressive remediation of groundwater that poses acute aquatic toxicity
hazards and gross contamination (odors, sheens) within ...
...50 meters of the shoreline
is also recommended. Long-term monitoring of remaining groundwater contamination
required (see text).
...
...of contaminants
over time, etc. When practicable, full cleanup of contaminated soil and groundwater
to permit future, unrestricted use of the property is desirable. A detailed discussion
...
...capping
of contaminated soil to prevent exposure or leaching, long-term monitoring of groundwater,
etc. These actions must be described in a site-specific EHMP. The preparation of
...
13.6 PREPARATION OF ENVIRONMENTAL HAZARD EVALUATION REPORTS
...HDOH document Screening for Environmental Hazards at Site
with Contaminated Soil and Groundwater (HDOH, 2016).
A summary of the type of information that should be included in the report is ...
... to-scale maps with a north arrow):
Identify all types of impacted media
(soil, groundwater, surface water, etc.).
Identify all sources of chemical
releases.
Identify initial ...
...and applicable (include maps of site
with isoconcentration contours for soil and groundwater as practicable).
Identify nearby groundwater extraction
wells, bodies of surface water ...
...as practicable).
Identify nearby groundwater extraction
wells, bodies of surface water and other potentially sensitive ecological habitats.
...
...risk assessment (in
addition to an Environmental Hazard Evaluation)?
Do soil and groundwater conditions
at the site differ significantly from those assumed in development of the lookup
...
...noncarcinogenic health effects been identified?
Selection of soil and groundwater
categories:
State the regulatory beneficial use
of impacted or potentially ...
...
State the regulatory beneficial use
of impacted or potentially impacted groundwater beneath the site; discuss the actual,
likely beneficial use of groundwater based on measured ...
...beneath the site; discuss the actual,
likely beneficial use of groundwater based on measured or assumed quality of the
groundwater and the hydrogeologic nature of the ...
...based on measured or assumed quality of the
groundwater and the hydrogeologic nature of the soil or bedrock containing the groundwater.
Characterize ...
...and the hydrogeologic nature of the soil or bedrock containing the groundwater.
Characterize the soil type(s) and
location of impacted soil as applicable to ...
... Compare site data to the selected
summary Tier 1 EALs and identify areas of soil or groundwater that pose potential
environmental hazards.
Identification of potential ...
... to assess the need for potential cleanup actions at sites where contaminated soil
and groundwater are identified.
...
14.2 Removal Actions for Non-Emergency Environmental Cleanups
...2016] for soil
and surface waters)
Reducing possible future impacts to groundwater
Restoring the pond to stable conditions where vegetation and animals may be re-established
...
...longer-term threats posed by residual contamination
of subsurface soils and non-drinking groundwater also exist, these less imminent
hazards may be left for a non-emergency removal or remedial ...
15.1 FTC Overview
... entitled the "Evaluation of Environmental Hazards at Sites with Contaminated Soil
and Groundwater" (HDOH, 2016).
15.1.1 Difference from Other Approaches
While ...
15.3 Screening And Eligibility
... Contamination that is known or likely to extend across a property boundary
Groundwater contamination, especially in a drinking water aquifer
Soil contamination that has a migration ...
15.5 Site Assessment Process
...characterize site conditions in order to identify
the necessity for remediating soil or groundwater that poses unacceptable environmental
hazards, either under current site conditions or under ...
... The site assessment is carried out by the collection and analyses of samples of
soil, groundwater, soil gas, surface water, sediment, air and/or other media as
needed. The EALs may be used ...
...presence or absence
of potential hazards may be identified and the contaminated soil or groundwater
quickly remediated without further assessment. In cases where cleanup costs could
...
15.6 Site Cleanup Process
... Cause of release or threat
Site history
General site geology, hydrology, groundwater status, adjacent land uses
Distance to surface water bodies
Site investigation and ...
Contents
...
16.2.2.4
Groundwater Remedial Actions
...
16.0 Remedial Actions
...may decide on a remedial action approach under the
following conditions:
Groundwater contamination, especially in a drinking water aquifer
Soil contamination with a direct migration ...
...with a direct migration pathway to a nearby drinking water aquifer
Contamination (soil or groundwater) crosses property boundaries
Contaminants are present at high levels or consist of complex ...
16.1 Conducting a Remedial Investigation
...sites, municipal
landfills, volatile organic compounds (VOCs) in soils, and contaminated groundwater
for Comprehensive Environmental Response, Compensation & Liability Act (CERCLA)
...
16.2 Setting Remedial Action Objectives and Conducting a Remedial Alternatives Analysis
...Refer to the EALs provided in Evaluation of Hazards at
Sites with Contaminated Soil and Groundwater (HDOH, 2016).
Known or suspected carcinogens: Cleanup levels should be concentrations ...
... to the EALs provided in Evaluation of Hazards at Sites with Contaminated Soil and
Groundwater (HDOH, 2016).
Ecological receptors: Where these concerns are identified, cleanup levels
...
... Soil vapor extraction to extract volatile contaminants from subsurface soils
Groundwater extraction, filtration by activated carbon, and disposal of the carbon
in an approved ...
...vapor barriers or active ventilation systems
On-site containment of contaminated groundwater with sheet piles or slurry walls
Reducing mobility of free phase petroleum in soil ...
...sheet piles or slurry walls
Reducing mobility of free phase petroleum in soil or groundwater by removing petroleum
to residual saturation or less
...
... left in place is disturbed in the future.
Long-term monitoring of a "stable" groundwater contaminant plume
Public notices and advisories against consumption of contaminated ...
..."free product" from the water table to prevent continued
contamination of soil and groundwater
Cleanup of contaminated soil to prevent direct exposure to the public
Cleanup of contaminated ...
...direct exposure to the public
Cleanup of contaminated soil to prevent leaching impacts to groundwater
When remedial alternatives for source control actions are developed, the remedial
...
...and, as necessary, institutional
controls.
16.2.2.4 Groundwater Remedial Actions
Analysis of remedial alternatives for groundwater contamination must ...
...Remedial Actions
Analysis of remedial alternatives for groundwater contamination must assess varying
restoration time periods utilizing different cleanup technologies.
...
16.4 Implementing the Cleanup Remedy Selected
...remedial design
prior to remedial action implementation. In some cases, such as at groundwater cleanup
sites, once the remedial system has been constructed and installed, it may operate
...
...generated at sites where long-term
cleanup or monitoring activities are planned, such as groundwater treatment and
monitoring, or periodic inspections of engineered controls such as soil caps. ...
18.4 Common Report Elements
...
Climate
Soils/Geology/Hydrology
Surface Water
Groundwater (including location of drinking water and other known wells on or near
to the site)
...
18.5 Document Outlines
...
Actual or probable release to groundwater that is a drinking water supply
...
...
2.1.4
Groundwater
...
...
5.2
Groundwater Sampling Activities
...
...
2.1.4
Groundwater
...
...
5.2
Groundwater Sampling Activities
...
...
6.2
Analytical Results of Groundwater Samples
...
...
2.1.4
Groundwater
...
...
5.3
Groundwater Investigation
...
...
6.3
Groundwater Sampling Procedures
...
...
2.1.4
Groundwater
...
...
5.4
Groundwater Sampling Activities
...
...
7.3
Groundwater Sampling Observations
...
...
8.1.3
Groundwater Samples
...
...
9.3
Groundwater Sampling Analytical Results
...
...
10.3
& Groundwater
...
... document Evaluation of Environmental Hazards at Sites
with Contaminated Soil and Groundwater (HDOH, 2016)
for a detailed discussion of Environmental Hazard Evaluation. A suggested outline
...
...
2.1.4
Groundwater
...
...
9.3
Targeted Tier 1 Groundwater EALs
...
...
9.4
Comparison of Selected Groundwater EALs to Site Data
...
...
2.1.4
Groundwater
...
...
2.1.4
Groundwater
...
...
5.5
Groundwater Sampling Activities
...
...
2.1.4
Groundwater
...
...
6.2
Groundwater Sampling Activities
...
...
9.0
Soil and Groundwater Management for Future Site Activities
Affecting On-Site Contamination
...
... 9.2
Pre-Excavation Evaluation of Soils and Groundwater
...
...
9.6
Groundwater Handling
...
...
9.7
Groundwater Disposal
10.0
...
18.6 Supporting Forms and Other Documents
...6, Figure 6-7.
18.6.3 Monitoring Well Abandonment Form
A groundwater monitoring well that is no longer needed, sustains damage, or is determined
to be improperly ...
... Owner Information
Well Construction Information, including installation date, depth to groundwater,
casing and screening material, etc.
General Abandonment Information, including ...
Contents
...
Long-Term Management of Petroleum-Contaminated Soil and Groundwater
...
19.1 Site Closure Scoping
...implications
include:
Will the remedy restrict future land (or groundwater) use at the site?
Will stakeholders concur with the land use restrictions?
Will current ...
...prospective purchasers in future real estate
transactions if contaminated soil and/or groundwater remains on site?
What will be the long-term costs of institutional and engineering controls ...
...effective
in preventing future site occupants from digging into contaminated soil or groundwater?
What potential legal liabilities may be caused by managing contaminated soil or
...
... What potential legal liabilities may be caused by managing contaminated soil or
groundwater on site? Are landowners and other stakeholders willing to accept those
liabilities?
...
19.3 Closures with Use Restrictions
...applied in situations
where representative contaminant levels are above the soil or groundwater "residential
use" EALs, but below applicable "commercial/industrial use" EALs at a site zoned
...
19.4 No Further Active Remediation Letter
...conditions of further work when (or if) the site is redeveloped.
The need for on-going groundwater monitoring or soil gas monitoring may indicate
a No Further Active Remediation Letter is not ...
...is presented
in HDOH guidance on Long-Term Management of Petroleum-Contaminated Soils and Groundwater
(HDOH, 2007c; included as Appendix
19-A). This document outlines procedures for ...
19.6 Environmental Hazard Management Plan
... capping of contaminated soil to prevent exposure or leaching, or long-term monitoring
of groundwater, etc.
The EHMP must include the following at a minimum (also see
Section ...
... Clear depiction of the extent and magnitude of remaining contamination in soil,
groundwater and/or soil gas, presented on easily readable, to-scale maps with a
north arrow
...
...environmental hazards
Requirements for long-term monitoring of contaminants in soil, groundwater, and/or
soil gas
Discussion of engineering and/or institutional controls needed ...
...pathways
Guidance on proper handling, reuse and disposal of contaminated soil and/or groundwater
that is encountered during future site activities
Specific description of construction ...
19.7 Institutional and engineering Controls
...measures include:
Prohibition on excavation of soil
Prohibition on use of groundwater
Prohibition on residential or other sensitive land use
HDOH's primary ...
... unlined borrow pits may be adequate for on-site management.
Groundwater Contamination
Hydraulic Containment � measures are used to control the hydraulic gradient ...
...� measures are used to control the hydraulic gradient to minimize
the spread of a groundwater plume. One example is the use of pumping wells to actively
prevent the plume from spreading ...
...permeability
materials, such as grout, are injected into the subsurface to contain a groundwater
plume. Institutional controls are necessary to restrict groundwater use.
Alternative ...
... plume. Institutional controls are necessary to restrict groundwater use.
Alternative Water Source � an alternative water source can be provided to an area
...
...Water Source � an alternative water source can be provided to an area
where groundwater is contaminated and not suitable for ingestion. Institutional
controls are necessary to ...
...and not suitable for ingestion. Institutional
controls are necessary to restrict groundwater use.
Sediment Contamination
Capping systems - contaminated sediments ...
Log of TGM Updates
...
6
Groundwater and Surface Water Sampling Guidance
Dec 31, 2008
...
...
Screening for Environmental Hazards at Sites with Contaminated Soil and Groundwater
Feb, 2005
Listed in additional ...
PDF Download Page
...
Section 6 - Groundwater
and Surface Water Sampling Guidance
...
... Appendix 19-A - Long-Term
Management of Petroleumcontaminated Soil and Groundwater
231kb
...
... Long-term Management
of Petroleum-Contaminated Soil and Groundwater.
161kb
...
Additional Guidance Documents" Language="VB" MasterPageFile="~/lib/Content.master
... and estimate contaminant concentration in source area leachate and in groundwater.
Refer to April 12, 2007 guidance on "Use of Laboratory ...
... Soil:
Guidance for assessing the potential impact to groundwater posed by leaching of
contaminants from vadose-zone soils. This model uses site-specific ...
...estimate contaminant concentrations in soil leachate
and future impacts to groundwater based on leachate dilution assumptions.
See October 2008 ...
...
Screening for Environmental Hazards at Sites with Contaminated Soil and Groundwater
(or "EHE Guidance"). The HEER Office EHE Guidance and HEER Office TGM are the two
...
...
Environmental Action Levels for Soil, Soil Gas, and Groundwater
Environmental Action Levels Surfer (electronic lookup tables)
...
...direct
exposure, vapor intrusion, leaching and contamination of groundwater, impacts to
drinking water resources, impacts to aquatic and terrestrial ...
7.10 Documentation of Soil Vapor or Indoor Air Sampling
... the magnitude and nature of subsurface contamination (e.g., free product on shallow
groundwater), concentrations of targeted VOCs in source area and subslab soil vapor
samples, presence or ...
7.10 Documentation of Soil Vapor or Indoor Air Sampling
...In general,
passive sample collectors should be deployed as near to the suspected soil or groundwater
source as possible in order to reduce the chance of placing the sampler in a pocket
...
7.10 Documentation of Soil Vapor or Indoor Air Sampling
...of petroleum fuels, including
diesel and other middle distillate fuels. Unlike soil or groundwater, reporting
of TPH compounds as �gasoline-range� or �diesel-range� is not applicable to soil
...
...level (see also Volume 1 of the EHE guidance).
Do soil or groundwater analytical results, or other field data, indicate that concentrations
of chemicals ...
7.10 Documentation of Soil Vapor or Indoor Air Sampling
...vapor concentrations
significantly higher than would otherwise be predicted by soil or groundwater data,
see HDOH 2016):
Unidentified source in nearby, vadose-zone
...
...in vapor
phase (e.g., PCE vapors in dry soil beneath slab of a dry cleaner);
Groundwater source area closer than
ten feet from soil vapor sample point (default depth to water table ...
...from discrete samples is very low; see Section
4);
Non-representative groundwater data
(e.g., heterogeneous plume with isolated �hot spots� nearby); or
Relict vapor ...
... Relict vapor plume associated with
earlier migration of more heavily contaminated groundwater through area in past
or post remediation of groundwater contamination.
...
...through area in past
or post remediation of groundwater contamination.
The heterogeneity of contaminants in groundwater plumes has not ...
...contamination.
The heterogeneity of contaminants in groundwater plumes has not been studied in
detail. Heterogeneity can be expected to be significantly greater ...
...among others:
Source area size and volume (e.g.,
free product on groundwater >100m2 in area and/or >10m3
contaminated soil present; refer to HDOH 2007c);
...
...2007c);
Mass of VOCs present in the source
media (e.g., soil or groundwater) and associated volume of contaminated soil necessary
to sustain long-term, vapor emissions ...
...are associated with a relatively
small source area of petroleum-contaminated soil or groundwater. In contrast, measures
to eliminate potential vapor pathways might be required at a site where ...
...regardless of the absence 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 ...
...the HDOH technical memorandum Long-Term Management of Petroleum-Contaminated Soil
and Groundwater (HDOH 2007c).
As a general rule a home or building should not be flagged for potential
...
...and within
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 ...
7.10 Documentation of Soil Vapor or Indoor Air Sampling
...soil vapor or indoor air sampling locations. The relative
location of soil and groundwater contamination with respect to locations of sampling
probes and all current or proposed future ...
13.7 HUMAN HEALTH RISK ASSESSMENTS
... for each environmental medium (e.g., COPCs for soil may be different that the COPCs
for groundwater). The identified list of COPCs will be the focus of the HHRA.
13.7.1.2 EXPOSURE ...
Appendices
...
Long-Term Management of Petroleum-Contaminated Soil and Groundwater.
...
Appendix 19-A Long-Term Management of Petroleum-Contaminated Soil and Groundwater
...
APPENDIX 19-A
Long-Term Management of Petroleum-Contaminated Soil and Groundwater.
(see PDF file)
...
9.6 Methamphetamine Laboratory Cleanup
...building if residues enter the heating,
ventilation and air-conditioning system. Soil or groundwater may become contaminated
if chemicals are disposed of in a septic system or dumped outside.
...
Appendix 9-B Initial Shortlist of Pesticides Used in Sugarcane and Pineapple Operations
...
1
Montgomery, J.H. 2000. Groundwater Chemicals. Desk Reference (3rd Ed).
...
...
8
Knisel & Davis. 2000. Groundwater Loading Effects of Agricultural Management
Systems.
...
Appendix 9-D Guidance Fact Sheet for Use When Petroleum Contamination is Encountered
...surface water, or any navigable water of the State.
Any free product that appears on groundwater.
Any amount of oil released to the environment greater than 25 gallons.
Any ...
...Office (808) 586-4249 during business hours for assistance.
Groundwater Management:
Groundwater that contains free product or a sheen can ...
...Management:
Groundwater that contains free product or a sheen can assumed to be contaminated
with dissolved ...
...disposal, or discharge
are all acceptable options for the disposition of groundwater generated during subsurface
excavation that encounters contaminated groundwater. Of ...
...generated during subsurface
excavation that encounters contaminated groundwater. Of these choices, re-infiltration
within the Work Area where the water was extracted ...
...water was extracted is the least expensive and easiest
way to manage contaminated groundwater; however this option may not be feasible
at all project locations.
...
...feasible
at all project locations.
Groundwater should be reused within the Work Area and within the same aquifer where
it ...
...
At a minimum, all groundwater discharged to storm sewers must be analyzed for constituents
...
... the vicinity of the work area.
The groundwater must be analyzed for known or suspected contaminants and the results
...
...Hazards at Sites with Contaminated Soil
and Groundwater, Fall 2011 Updates, Revised January 2012 (and updates)
For some ...
...
The trench must be within the Work Area, especially if the groundwater is extracted
from a Work Area in the vicinity of known or observed ...
5.10 Investigation Derived Waste
...with detergent/wash water mixes avoided.
Management and disposal of waste groundwater generated during developing and purging
activities is discussed in Section 6 and summarized ...
...immediately downgradient
of the well provided that it is generated from the uppermost groundwater unit, is
not impacted above action levels applicable to the site, does not contain free product
...
8.5 FIELD SCREENING WITH CONE PENETROMETER AND SENSORS/PROBES
...deploy. The devices developed for these platforms
are: samplers for soil, soil gas and groundwater; geotechnical sensors for soil
texture and hydraulic conductivity; and chemical sensor sampling ...
...with grain size but also with soil
water content and ionic strength of the pore water or groundwater. Ionic strength
of the groundwater can change due to contaminant content. Dense non-aqueous ...
...Ionic strength
of the groundwater can change due to contaminant content. Dense non-aqueous phase
liquids (DNAPL) have a very ...
...can be used to determine the hydraulic conductivity of subsurface soils
and the depth to groundwater. These data can be used to identify potential contaminant
pathways in the subsurface, or to ...
...Hydrosparge™ systems for the detection of
volatile organic compounds in soil and groundwater (USEPA 2004 and
2005).
USEPA evaluation of chemical sensors used with ...
...a method for real-time,
in situ, field screening of hydrocarbons in subsurface soil and groundwater.
The technologies are intended to provide highly detailed, qualitative to semi-quantitative
...
...heat to
volatilize and mobilize contaminants for sampling. Heating the soil and/or groundwater
adjacent to the MIP�s semi-permeable membrane volatilizes the VOCs, which then pass
...
...near the membrane to 80 to 125 �C (160 to 232 �F), which allows VOCs in
the soil and groundwater to partition across the membrane in saturated or unsaturated
soil. The subsurface temperature ...
... in the soil�s electrical behavior that can be related to changes in stratigraphy
or groundwater quality. Analytical devices commonly used with an MIP include gas
chromatography (GC)-grade ...
...provide screening-level data
that need to be supplemented with analytical soil or groundwater data to fully support
human health risk assessments or remediation decisions.
...
8.6 FIELD SCREENING EQUIPMENT TO SUPPORT HEALTH AND SAFETY PROGRAMS
...instruments discussed in the following subsections
are typically used during soil and groundwater investigations. Additional air monitoring,
radiation monitoring or other specialized equipment ...