Cleanup Levels for CERCLA Remedial Actions

Transcription

1 Cleanup Levels for CERCLA Remedial Actions Presented October 10, 2014 David M. Buxbaum, Senior Attorney U.S. EPA Region IV Office of Regional Counsel The information provided in the presentation is based upon CERCLA, the NCP, and available EPA policy and guidance. This presentation does not represent any official Agency position with respect to the matters covered. 1

2 Overview of CERCLA Remedy Selection Process Scoping of Remedial Investigation (RI). Remedial Investigation includes Baseline Risk Assessment (BRA). Feasibility Study (FS). Proposed Plan (along with Notice of Availability to Public). Record of Decision (ROD). CERCLA Section 121(a) (Selection of remedial action), provides that remedial action under Sections 104 or 106 of CERCLA shall be carried out in accordance with Section 121 (Cleanup standards) and, to the extent practicable, the NCP. The overarching mandate of the Superfund program is protect human health and the environment from current and potential threats posed by uncontrolled hazardous waste sites. 2

3 CERCLA Degree of Cleanup Under Section 121(d)(1) remedial actions shall attain a degree of cleanup which assures protection of human health and the environment. Remedial actions shall attain ARARs: any standard, requirement, criteria, or limitation under federal environmental law or more stringent promulgated standard, requirement, criteria or limitation under State environmental or facility siting law that is legally applicable to the hazardous substance (or pollutant or contaminant) concerned or is relevant and appropriate under the circumstances of the release. Remedy shall attain ARARs unless in limited circumstances it is determined one of the waivers specified in Section 121(d)(4) can be invoked. [See also 40 CFR (f)(1)(ii)(B) and (C)] 3

4 ARAR Compliance under NCP Overall protection of human health and the environment and compliance with ARARs are threshold requirements that each remedial alternative must meet in order to be eligible for selection. [Ref 40 CFR (f)(1)(i)(A)] On-site remedial actions selected in a ROD must attain those ARARs that are identified at the time of ROD signature or provide grounds for a waiver. [Ref 40 CFR (f)(1)(ii)(B)] The ROD shall describe the federal and state ARARs that remedy will attain or will not meet, the waiver invoked, and the justification for invoking the waiver. [Ref 40 CFR (f)(5)(ii)(B) and (C)] 4

5 ARARs Purpose CERCLA 121(d) added by Congress with 1986 SARA which codifies EPA s approach to compliance with other laws. EPA uses standards from other environmental laws to help select cleanup levels and design response actions at CERCLA sites. ARARs are enforceable substantive standards, requirements, criteria or limitations borrowed from other federal or state environmental statutes and regulations. Compliance with ARARs often determines the cleanup standard at a site or certain requirements that the response action must meet depending on the location or actions taken at the site. ARARs divided into three categories for ease of identification Chemical-specific Location-specific Action-specific 5

6 Chemical-specific ARARs Promulgated health- or risk-based numerical values or methodologies which when applied to site-specific conditions, result in the establishment of numeric values. Establish an acceptable amount or concentration of a chemical that may remain in, or be discharged to, the ambient environment. Examples: Safe Drinking Water Act - MCLs for groundwater Clean Water Act - AWQC for surface water State cleanup levels - contaminant target levels for soil Identified early in the CERCLA process (RI Scoping) to determine the Contaminants of Concern. The lead agency shall initiate the identification of potential federal and state ARARs, and as appropriate, other criteria, advisories, or guidance to be considered. [Ref 40 CFR (b)(2)(9)] 6

7 Chemical-specific ARARs Example 7

8 To be considered (TBC) category Under 40 CFR (g)(3) both lead and support agencies may, as appropriate identify other advisories, criteria, or guidance to be considered for a particular release. TBCs are not potential ARARs because neither promulgated nor enforceable. However, proposed standards may be TBC. Considerable agency discretion in identifying TBCs. May be necessary to consult TBCs to interpret ARARs or to determine preliminary remediation goals when ARARs do not exist. Examples include health advisories, reference doses, EPA and State technical guidance on how to perform specific response activity. TBC must be attained to the same extent as ARARs if included in final ROD or other decision document. 8

9 Summary of RI and BRA RI determines the nature and extent of contamination and assesses the risks (human health and/or ecological) posed by the contamination. BRA characterizes the current and potential threats to human health and the environment that may be posed by contaminants migrating to ground water or surface water, releasing to air, leaching through soil, remaining in the soil, and bioaccumulating in the food chain. [Ref. 40 CFR (d)(4)] Results of the BRA conducted as part of the RI (which includes exposure assessment, toxicity assessment, and risk characterization components) help establish acceptable exposure levels in the FS for use in developing remedial alternatives. 9

10 Establishment of PRGs during FS FS develops and evaluates remedial alternatives to address the contamination such that the remedial action options can be reviewed and an appropriate remedy be selected. FS process involves developing remedial action objectives (RAOs) for protecting human health and the environment (which should specify contaminants and media of concern), potential exposure pathways, and preliminary remediation goals (PRGs). PRGs are developed based on readily available information such as chemical-specific ARARs or other information (e.g.,tbc). [Ref. 40 CFR (e)(2)(i)] PRGs may be modified by EPA based upon the results of BRA and waste management strategy selected at the time of remedy selection. 10

11 Development of Cleanup Levels Cleanup levels (or remediation goals) establish acceptable exposure levels that are protective of human health and the environment. Developed considering chemical-specific ARARs and risk-based levels (for systemic toxicants and known or suspected carcinogens). For carcinogens, the 10-6 risk level shall be used as the point of departure for determining remediation goals for alternatives when: ARARs are not available, or ARARs not sufficiently protective because of the presence of multiple contaminants at a site or multiple pathways of exposure. [Ref 40 CFR (e)(2)(i)(A)(2)] For non-carcinogens or systemic toxicants, the level shall not exceed a Hazard Quotient of 1. [Ref. 40 CFR (e)(2)(i)(A)(1)] TBC(s) may be used to establish cleanup level when ARARs not available. 11

12 Cleanup Levels con t For remedial actions of contaminated groundwater that is a current or potential drinking water source, non-zero MCLGs or MCLs under the SDWA shall be attained where relevant and appropriate. [Ref 40 CFR (e)(2)(i)(B)] For remedial actions addressing impacted surface water, AWQC under Sections 303 or 304 of the Clean Water Act shall be attained where relevant and appropriate. [Ref. 40 CFR (e)(2)(i)(E)] For remedial actions addressing contaminated soil, EPA will use ARARs where available, TBCs, or establish risk-based levels. EPA will set remediation goals for ecological and environmental effects based on environmental ARARs, where they exist, and levels based on site-specific determination to be protective of the environment. 12

13 ARARs/TBC Compliance Remediation goals shall be measured at appropriate locations in the groundwater, surface water, soils, air, and other affected environmental media. [Ref 40 CFR (f)(5)(iii)] Chemical-specific ARARs that were used to establish cleanup levels apply only at completion of the response action. ARARs must be measurable and attainable since purpose is to set a standard that an actual remedy can attain. Lead agency is responsible for ensuring that all ARARs identified in the ROD are met during the course of the RD/RA. [Ref 40 CFR (b)(2)] Generally, EPA policy is to attain ARARs and TBCs pertaining to contaminant levels or to performance or design standards so as to ensure protection at all points of potential exposure. [53 FR 51440] 13

14 ROD Requirements CERCLA Section 117(b) requires that EPA provide notice of the final remedial action plan (i.e., the Record of Decision or ROD ), and that the ROD be made available to the public before commencement of any remedial action. Lead agency (usually EPA) selects and documents the remedy selection for a site or operable unit ( OU ) in a ROD. [40 CFR (f)(4)] ROD must specify final cleanup levels for each medium (i.e., contaminant specific remediation goals) that the remedy is expected to achieve. [Ref. 40 CFR (f)(5)(iii)(A)] ROD should identify the basis for cleanup levels (ARARs, TBC or risk-based). 14

15 ARARs Frozen at ROD Once a ROD is signed and a remedy chosen, EPA will not reopen that decision based on modified or newly promulgated ARARs unless calls into question the protectiveness of the remedy. EPA believes it is necessary to freeze ARARs when the ROD is signed rather than upon initiation of the remedial action because continually changing remedies to accommodate new or modified requirements would disrupt CERCLA cleanups, whether the remedy is in design, construction, or in remedial action. Identification of new ARARs that significantly affect the remedy in terms of protectiveness, scope, cost, performance etc. would require an ESD or ROD Amendment depending on the extent of the post ROD changes to the remedy. 15

16 Five-Year Review CERCLA Section 121(c) requires periodic reviews (at least every five years) at sites where the remedial action leaves hazardous substances, pollutants or contaminants on-site above UU/UE. In addition, a review will be conducted at sites where substances remain on-site if the standards initially used to define protective exposure levels are subsequently changed. The purpose of a five-year review is to evaluate the implementation and performance of a remedy in order to determine if the remedy is or will be protective of human health and the environment. See EPA, OSWER No B-P, Comprehensive Five-Year Review Guidance, June

17 Determining Protectiveness The following questions should be examined: 1) Is the remedy functioning as intended by the decision documents?; 2) Are the exposure assumptions, toxicity data, cleanup levels, and RAOs used at the time of the remedy selection still valid?; and 3) Has any other information come to light that could call into question the protectiveness of the remedy. If the periodic review shows that a remedy is no longer protective of human health and the environment, additional action will be evaluated and taken to mitigate the threat. [53 Fed. Reg , (Dec. 21, 1988)]. 17

18 Question #2 EPA considers the following that could call into question the protectiveness of the remedy: changes in ARARs identified in the ROD; newly promulgated standards; changes in TBCs identified in the ROD; changes in land use or anticipated land use on or near the site; new human health or ecological exposure pathways of receptors have been identified; new contaminants or contaminant sources have been identified, changes in the physical site conditions, and changes in toxicity factors for COCs. 18

19 Examples Requiring Review Consideration of the vapor intrusion pathway and indoor exposure from VOCs in soil and groundwater. Many older remedies may not have characterized and assessed whether contamination presents unacceptable risk of exposure to human health. Groundwater sampling reveals new COC present that either was not analyzed in the RI, new detection methods available, or contaminant is daughter product from degradation of VOC (e.g. vinyl chloride). Discovery of new soil contamination from land-disturbing activity, or discovery of new sources (e.g., DNAPL) from groundwater monitoring. Toxicity factors of COC re-evaluated by Agency and results in recommendation of a lower concentration to be protective. 19

20 Take Away Points Under Section 121(d)(1) remedial actions shall attain a degree of cleanup which assures protection of human health and the environment. CERCLA Section 121(d) Cleanup standards and NCP provide the process for identifying cleanup levels that are protective of HH&E. Chemical-specific ARARs often the basis for cleanup levels, but TBCs may used or risk-based concentration established where ARARs not available or determined to be not protective. Per CERCLA Section 121(c), EPA reviews remedy protectiveness where contamination remains above UU/UE level. Changes to cleanup levels guided by Five-Year Review process to determine if change necessary. 20