Colorado's Conditional Closure Policy and Guidance: Risk-Based Approach to Ground Water Cleanups

Colorado's Conditional Closure Policy and Guidance: Risk-Based Approach to Ground Water Cleanups Walter Avramenko Colorado Department of Public Health and Environment May 3, 2012

In the beginning Evolution of Remedial Technologies Evolution in Thinking Changing Universe of Facilities

Colorado Basic Ground Water Standards Water Quality Control Commission - establish State-wide standards - strict standards for chlorinated solvents Department of Public Health and Environment - implementing agency All cleanup goals must achieve State standards WQCC has sole authority for granting waivers

Difficulties Achieving Standards Recalcitrant chemicals - Chlorinated compounds Hydrogeologic environments - Fractured bedrock aquifers - Fine-grained formations Lack of resources - limited funds available - law of diminishing returns

Standards =/ Threat Meeting numeric standards in an expedited fashion may be difficult to achieve without expending considerable resources, out of proportion to the risks posed by the contamination - it is found at depth - poor quality / insufficient quantity - it is not moving - is naturally attenuating - no one is using the ground water - does not pose a vapor intrusion risk No exposure = No threat / risk

Evolution in Thinking and Approach On July 12, 2001, SB 01-145 became effective, creating authority for environmental covenants A mechanism to ensure that institutional controls are properly implemented and that engineered structures are protected and maintained, so that remedies continue to be protective for as long as any residual contamination remains a risk Prior to 2001, the goal had to be unrestricted use

Evolution in Thinking and Approach July 24, 2002: GUIDANCE FOR DETERMINING THE LENGTH OF TIME NECESSARY TO MONITOR GROUND WATER QUALITY Frequency of monitoring may vary depending on site-specific circumstances Drafted for purposes of ensuring consistency amongst my staff

Internal Discussions To come up with a set of criteria by which it can make a decision that no further action is needed before all areas of a ground water plume have been successfully remediated to state standards Focused on source control measures, data trends, natural attenuation, risk evaluation and the use risk management tools to prove the residual contamination will pose no risk to human health and environment

List Of Possible NFA Criteria 10 to 12 identified Draft criteria underwent a process of review and modification The assumption is that all criteria must be met in order to justify an NFA Supporting documentation must be provided Choice of last resort: when the best available remedial efforts are proving unsuccessful at meeting desired goals

Source Areas Remediated A key requirement of any cleanup if we expect ground water quality to improve Cause of the release eliminated Contaminated soil and NAPL eliminated Mass of sorbed contamination in downgradient formation materials may need to be reduced to the extent possible

Plume Stable or Decreasing A requirement in all dimensions Based on adequate data (measured in years) Plume stability or shrinkage not dependent on active measures We are confident that site conditions will not change to cause a resumption in movement and an expansion of the plume

Natural Attenuation Natural attenuation occurring Some effort to understand and document the mechanism Estimate on the rate of decline Not dependent on active measures Standards met within a reasonable time Reasonable time based on risk to receptors and existing/future land use

No Exposure To Contaminants No present or future exposures No ground water users threatened Not dependent on active measures No cross media transfers: - indoor air - surface water or other aquifers - agricultural or other non-domestic uses

Institutional Controls Environmental covenant, restrictive notice, or intergovernmental agreement placed on all affected properties Restricts use of ground water and any other activities that could potentially cause the plume to move/expand or result in exposures All affected properties notified

Remediation Goal Still The Same State ground water standards Remedial actions meant to move the site in that direction We have discretion deciding how long it takes to get there Risk management is used to decide how long and what level of long-term monitoring and involvement

Caveats Not a substitute for remediation a good faith effort must be made to remediate affected media This is not a technical impractability determination Department s determination may change based on new information Does not preclude the State from seeking damages related to the injury of the resource

Eligible Sites Low threat sites that have a good chance of attaining standards within reasonable timeframes - relatively low concentrations - limited extent - effective actions to remediate - pose low to no threat

Guidance / Policy Development Draft Guidance for the Closure of Low-Threat Sites with Residual Ground Water Contamination Draft Policy for Making Conditional Closure Determinations Late 2010 public comment period A little over a dozen set of comments received Most comments could be satisfied by amending the guidance document Except for EPA s comments

EPA s Comments The proposed policy and guidance are in direct conflict with the ground water monitoring requirements of both federal and state RCRA programs Therefore, the proposed policy and guidance should clarify that they only apply to sites with contaminant concentrations less than MCLs or other cleanup standards, or sites that do not have hazardous constituents

Basis For EPA s Conclusion 264.90(a)(2): Sites where hazardous constituents / waste has been disposed of after July 26, 1982 (hereinafter referred to as a "regulated unit") must comply with the requirements of 264.91 through 264.100 for purposes of detecting, characterizing and responding to releases to the uppermost aquifer.

Basis For EPA s Conclusion 264.96(c) and 264.100(f): Regulated units must comply with all the requirements outlined in this subpart, including monitoring ground water until the owner or operator can demonstrate that the ground-water protection standard of Section 264.92 has not been exceeded for a period of three consecutive years.

The EPA Log Jam February 7, 2011 meeting: EPA dead set against applicability to RCRA facilities, the largest pool of facilities that might benefit from the guidance State seeks a formal legal opinion on the matter from EPA Region 8, HQ and their legal counsel

The EPA Log Jam April 18, 2011 letter to EPA: Legal questions on applicability and flexibility under RCRA Where EPA has allowed similar closures: Wisconsin s Case Closure Rule Florida s Risk-Based Corrective Action Rule Region 8 examples where they have OK ed similar decisions at our and their sites

EPA Responds Off the record: they agree with the approach No formal reply to our April 18, 2011 letter November 16, 2011 meeting: EPA gives conditional approval to proceed - Exclude traditional RCRA permitted TSD facilities - Exclude CERCLA / NPL-caliber sites - Does not limit EPA oversight / enforcement - 12 month pilot basis - EPA invited to first few examples

NFA CANDIDATE 1

NFA CANDIDATE 1 UMTRA remedial actions removed PCE source from under building Monitoring data do not suggest there is a lingering source of contamination beneath the building near former dry cleaning machines Only source of residual contamination is found near MW-8 PCE plume is confined to an area around MW-8, attenuating to below State ground water standards before it reaches downgradient wells Insufficient mass of residual PCE contamination is present in the soil to cause a significant plume under existing conditions.

ND 526 µg/l historic high 28 µg/l last sampled ND ND ND ND ND 1.7 µg/l ND

NFA CANDIDATE 1 continued NFA dependent on: Monitoring ground water quality in a limited number of on-site wells for several years to document the stability of a pocket of ground water contamination. Placing an environmental covenant on the property to prohibit the use of ground water in the affected area.

NFA CANDIDATE 1 continued Environmental Covenant specifies: Prohibits use of ground water or soil disturbing activities in the vicinity of the one contaminated well. Soil management plan defines what will need to be done in the event soil disturbing actives take place in the vicinity of MW08.

NFA CANDIDATE 2

NFA CANDIDATE 2 Source area remediated using soil vapor extraction Ground water treatment by injecting soylactate After several years of monitoring, contaminant levels in ground water have dropped and are continuing to decline Facility requests an NFA

ND 4 µg/l 4 µg/l ND 6 µg/l 12 µg/l 17 µg/l 10 µg/l ND 5 µg/l

NFA CANDIDATE 2 continued Potential problems to NFA request: - TOC levels are still elevated in some wells, suggesting bioremediation amendments are still present - Contamination has migrated onto an adjoining property, beyond the control of the NFA applicant

NFA CANDIDATE 2 continued Potential solutions: - Determine whether rebound has occurred in wells where TOC has declined and assume the similar results in the other wells - Obtain an environmental covenant for the adjoining property

NFA CANDIDATE 2 continued NFA granted if: - Rebound not anticipated - An environmental covenant is placed on the two affected properties limiting future use of ground water NOTE: WQCC scheduled to change PCE standard in August 2012, from 5 to 16.7 µg/l

Former Samsonite Corporation Facility Site 2003 Former Property Boundary Former Hardware Building Former Power Plant Building Former Assembly Building

NFA CANDIDATE 3 Originally built in 1967 to manufacture luggage Formerly used chlorinated solvents until mid 1990s Manufacturing discontinued in early 2000s Volatile Organic Compound (VOC) affected soil Former Hardware and Assembly Building areas

NFA CANDIDATE 3 continued Source Area Control: Soil Vapor Extraction (SVE) System Sumps and Oil/Water Separators sumps cleaned, excavated, soil confirmation samples collected Groundwater Treatment accelerated biodegradation HRC/HRC-X Groundwater injections over approximately 35,000 square feet Groundwater Monitoring: Ten monitoring well onsite, three monitoring wells offsite Quarterly Groundwater Monitoring and Annual Reporting from 2005 to 2007 Decrease in VOC concentrations in response to injections

Main Areas of Affected Groundwater Before Corrective Action

Former Property Boundary

Groundwater Concentrations - November 2011 (7 ppb) (5 ppb) (5 ppb)

NFA CANDIDATE 3 continued Policy mandated Review Board Potential problem: downgradient building prevents data collection to show determine if PCE/TCE greater than standards Some may demand that environmental covenant be placed on the downgradient property due to 14 ppb TCE Opportunity to see how process works and whether we need to amend documents

Walter Avramenko, Unit Leader Hazardous Waste Corrective Action Unit Solid and Hazardous Waste Program Hazardous Materials and Waste Management Division Colorado Department of Public Health and Environment HMWMD-HWC-B2 4300 Cherry Creek Drive South Denver, CO 80246-1530 303-692-3362 FAX: 303-759-5355 walter.avramenko@state.co.us