Department of Health Seal

TGM for the Implementation of the Hawai'i State Contingency Plan
Section 16.2
SETTING REMEDIAL ACTION OBJECTIVES AND CONDUCTING A REMEDIAL ALTERNATIVES ANALYSIS

16.2 SETTING REMEDIAL ACTION OBJECTIVES AND CONDUCTING A REMEDIAL ALTERNATIVES ANALYSIS (RAA)

Identifying the primary remedial action objectives is the first step in the RAA process. The objectives are specific goals to be achieved by the selected remedy; these will include fulfilling applicable requirements (See Subsection 16.2.1.1>). The remedial action objectives should identify questions requiring answers, site characteristics, chemicals of potential concern (COPCs), and potential outcomes.

Examples of remedial action objectives for a site with soil contamination are:

  • Remove exposure pathways between contaminants and receptors (either human or ecological receptors)
  • Achieve cleanup of soil to below applicable HDOH EALs for a residential (unrestricted use) scenario
  • Utilize USEPA presumptive remedies to the to the extent practicable
  • While conducting the cleanup, follow all applicable federal, state, and local regulations pertaining to the site and the response actions
  • Minimize potential adverse impacts to the community and the environment during implementation of the remedial action
  • Properly dispose of waste streams generated by the remedial action

The Remedial Alternatives Analysis (RAA) Report is a formal presentation of the evaluation of different possible cleanup measures (remedial alternatives) that could be taken in response to a particular release. Therefore, the RAA Report:

  • Identifies possible remedial alternatives
  • Analyzes each remedial alternative's effectiveness, implementability, and cost
  • Recommends a preferred remedial alternative

16.2.1 Threshold Criteria For Remedial Alternatives

All remedial alternatives evaluated must meet certain threshold criteria, described in subsections below. These are minimum requirements for a cleanup measure that may be considered for selection. If a cleanup measure cannot meet the threshold criteria, it is not an acceptable alternative and cannot be included in the remedial alternatives analysis.

16.2.1.1 Applicable Requirements

Remedial alternatives must comply with all applicable requirements, which are: any federal, state, or local requirements that are legally applicable to a hazardous substance, the response action, location, or other circumstance at a particular site. Examples of applicable requirements are:

  • Air pollution emission limits on an on-site incineration process - regulated by the United States (U.S.) Clean Air Act and HRS 342B.
  • Effluent discharge limits on wastewater discharges from an on-site treatment process - regulated by the U.S. Clean Water Act and HRS 342D.
  • Grading, stockpiling, trenching - regulated by various county ordinances.

However, these actions may not require state or county permits if the activity controlled by an applicable requirement will be conducted entirely on site, and if the response action involving the activity is being conducted in compliance with HRS 128D. In these cases, the remedial alternative being applied must comply with all substantive requirements of the law authorizing the actions (e.g. grading permits), since the law is an applicable requirement.

16.2.1.2 Human Health and Ecological Risk Levels

All remedial alternatives considered must use cleanup levels meeting the following criteria:

Systemic toxicants: Cleanup levels must represent concentrations to which the human population, including sensitive subgroups, may be exposed without adverse effect during a lifetime or part of a lifetime (as appropriate), incorporating an adequate margin of safety. 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 that represent an excess upper bound lifetime cancer risk to an individual of between 10E-4 and 10E-6, using information on the relationship between dose and response. The 10E-6 risk level will be used as the point of departure for determining acceptable cleanup levels for remedial alternatives in most situations, and when (1) individual chemical-specific federal or state cleanup levels are not available, or (2) individual chemical-specific federal or state cleanup levels are not sufficiently protective due to the presence of multiple contaminants or multiple pathways of exposure. Refer 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 should address impacts to ecological receptors. For example, on sites that have significant ecological risk concerns, the applicable HDOH Tier 1 EAL may be 200 mg/kg in soil rather than 400 mg/kg in soil for those sites where only human health concerns are being addressed. Alternatives for sites with ecological risk concerns must incorporate findings of any natural resource assessments conducted to address such impacts.

The HEER Office has developed an environmental hazard evaluation (EHE) process, presented in Section 13, to address these protectiveness criteria. Remedial actions that reduce contaminants below the appropriate HDOH Tier 1 EALs for the site will meet these criteria for protection of health and the environment. Information and lookup tables regarding HDOH EALs for specific contaminants is available in the guidance document (HDOH, 2016), and may be accessed quickly through the use of the on-line HDOH EAL "Surfer" tool

16.2.2 Development of Remedial Alternatives

If possible, a preliminary list of likely cleanup alternatives developed earlier in the remedial action process should be used as a starting point for the detailed development of remedial alternatives (see Subsection 16.1.2).

16.2.2.1 Hierarchy of Remedial Alternative Selection

A primary objective of any remedial action is to reduce the toxicity, mobility, volume, and extent of released hazardous substances. As noted in the Hawai`i SCP [HAR 11-451-8(c)] (HAR, 1995), all removal and remedial response actions should consider a hierarchy of response action alternatives in this descending order:

  1. Reuse or recycling
  2. Destruction or detoxification
  3. Separation, concentration, or volume reduction
  4. Immobilization of hazardous substances
  5. On-site or off-site disposal, isolation, or containment
  6. Institutional controls or long-term monitoring

When selecting and analyzing remedial action alternatives, this general hierarchy of response actions should be considered to help prioritize the alternatives.

  1. Reuse or recycling. Released hazardous substances may sometimes be directly reused or recycled after recovery, depending on the quality of the recovered materials. Examples include:
    • Reuse or recycling of recovered petroleum "free product" as motor fuel or boiler fuel
    • Recycling of metallic lead fragments as recycled scrap metal
  2. Destruction or detoxification. Organic hazardous substances can be destroyed or detoxified by altering their molecular structures, and, in principle, may be converted into carbon dioxide, water, and inorganic salts. Hazardous substances that pose a threat due to corrosivity or reactivity often can be neutralized. Examples include:
    • Biodegradation of organic hazardous substances
    • Combustion or incineration of organic hazardous substances
    • Neutralization of extremely acidic (low pH) or basic (high pH) corrosive substances
    •  Detonation of unexploded ordnance or other explosive substances
  3. Separation, concentration, or volume reduction. Contaminated material may be completely or partially separated from material that is not contaminated, or contamination may be reduced in a large volume of material by concentrating the contaminant in a smaller volume. Examples include:
    • Soil vapor extraction to extract volatile contaminants from subsurface soils
    • Groundwater extraction, filtration by activated carbon, and disposal of the carbon in an approved landfill
    • Soil particle size separation to reduce contaminated soil volume
  4. Immobilization of hazardous substances. The physical state of a contaminant may be changed so it is no longer mobile in the natural environment. Examples include:
    • Binding of mobile heavy metals into low-mobility phosphates, sulfides, etc.
    • Chemical additives to reduce the bioavailability of contaminants
    • Vitrification of contaminated soil
  5. On-site or off-site disposal, isolation, or containment. Contaminated material may be placed in an engineered facility or feature designed to minimize future release of hazardous substances and in accordance with applicable requirements. Examples include:
    • Off-site disposal at permitted landfills
    • On-site isolation of contaminated soil by covering the soil with a concrete cap
    • On-site containment of soil gas with 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 or groundwater by removing petroleum to residual saturation or less
  6. Institutional controls or long-term monitoring. Site uses may be restricted through administrative methods and/or long-term monitoring to assess changes in contaminant distribution over time. Examples include:
    • Environmental covenant to prohibit disturbance of contaminated soil
    • Establishment of a monetary trust to fund environmental response efforts if contamination 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 foodstuffs

16.2.2.2 Preliminary Screening of Alternatives

Initial identification of all potentially applicable remedial alternatives should be fairly broad. This initial list of alternatives can be narrowed by ruling out those alternatives that, while applicable in theory, will not work at the site due to factors such as site conditions or technology limitations. Typically, a minimum of five alternatives are considered initially, one of which is the null or "no action" alternative to use as a baseline.

A comparison table depicting the various alternatives considered, practicality of implementation at the site, and costs associated with each option will assist in clearly documenting the advantages and disadvantages of each alternative considered. Generally, at least 3 alternatives that have been screened and judged potentially feasible and practical for the site are carried forward for more in-depth review and analysis (see Subsection 16.2.3). In some cases, the remedy eventually selected will be a combination of remedial actions that are required to achieve the remedial action objective.

16.2.2.3 Source Control Actions

A "source control action" prevents the continued release of hazardous substances into the environment, primarily from a source on top of or within the ground, or in buildings or other structures. Typical source control actions include:

  • Removal of hazardous substances from drums, tanks, or pipelines to prevent leakage into the ground
  • Removal of floating petroleum "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 soil to prevent leaching impacts to groundwater

When remedial alternatives for source control actions are developed, the remedial alternatives analysis should present:

  • At least one alternative where the principal element is treatment that reduces the toxicity, mobility, or volume of the hazardous substances. As appropriate, a range of treatment alternatives should be presented, including:
    • An alternative that removes or destroys hazardous substances to the maximum extent feasible, eliminating or minimizing the need for long-term management.
    • Alternatives that vary in the degree of treatment used and the residuals and untreated wastes that must be managed.
  • At least one alternative where protection is provided primarily by preventing or controlling exposure through engineering controls and, as necessary, institutional controls.

16.2.2.4 Groundwater Remedial Actions

Analysis of remedial alternatives for groundwater contamination must assess varying restoration time periods utilizing different cleanup technologies.

16.2.3 Evaluation of Cleanup Alternatives

Once all potential remedial alternatives are identified and screened to eliminate those that are not practical or technologically feasible at the site, the remaining alternatives are further evaluated relative to each other. The additional evaluation is based on three criteria:

  • Effectiveness
  • Implementability
  • Cost

As noted previously, the evaluation of selected remedial alternatives should be presented in a table format. The table should be supplemented with detail provided in narrative form. For example, the narrative text could present the criteria used for detailed evaluation of remedial alternatives, and a table could summarize the main considerations in the detailed analysis of remedial alternatives selected. Concise summary presentation of remedial alternative comparisons is very helpful with respect to public participation requirements (see Subsection 16.3.2)

Based on the evaluation of these criteria, a preferred alternative (or combination or remedial actions) that meets the site's remedial objectives is selected by the responsible party/site consultant and identified in the results or summary portion of the RAA report (see Subsection 16.2.4)

16.2.3.1 Effectiveness

Effectiveness means the degree to which an alternative:

  • Reduces toxicity, mobility, and volume through treatment
  • Minimizes residual risks
  • Affords reliable long-term protection
  • Complies with applicable requirements
  • Minimizes short-term impacts
  • Quickly achieves protection

Effectiveness must consider both short-term and long-term elements.

16.2.3.2 Implementability

Implementability means the technical and administrative feasibility of the alternative:

Technical feasibility includes:

  • Availability of equipment, facilities, and specialists needed
  • Compatibility of the technology with site conditions

Administrative feasibility includes:

  • Availability of necessary approvals
  • Degree of community acceptance

16.2.3.3 Costs

Each alternative must be considered in terms of total life-cycle cost, not just the up-front capital cost. This is especially important when evaluating alternatives that involve long-term operation and maintenance or other long-term costs that may be incurred by current or future responsible parties. Costs evaluated should include:

  • Capital costs
    • Direct construction costs
    • Indirect costs
    • Opportunity costs imposed by the remedial alternative (for example, reduction in property value due to activity and use limitations)
  • Annual cost of operation and maintenance (O&M)
    • Sampling and analysis, equipment maintenance, labor
    • Oversight costs (HEER Office or private consultant)
    • Opportunity cost (for example, reduction in annual revenue due to activity and use limitations)
  • Contingency costs – possible cost of repairs / restoration in case of remedy failure

Costs should be presented in two formats: (1) as a lump-sum dollar amount in current dollars, with future costs amortized; and (2) as a graph showing projected costs over time.

16.2.4 Remedial Alternatives Analysis Report

The RAA report presents a concise discussion of the remedial alternatives identification and evaluation process for the site, including rationale for the preferred alternative. The content and level of detail in the RAA report will vary depending on the nature and extent of the release, as well as the remedial action or combination of remedial actions selected. The completed report is submitted to the HEER Office for review and comment. See Section 18 for an example outline of a RAA report.