Alternatives for Managing the Nation s Complex Contaminated Groundwater Sites

Transcription

1 Alternatives for Managing the Nation s Complex Contaminated Groundwater Sites Webinar 1 pm Eastern Time Zone Wednesday December 12, 2012 Water Science and Technology Board National Research Council

2 Committee on Future Options for Management in the Nation s Subsurface Remediation Effort MICHAEL KAVANAUGH, NAE, Chair, Geosyntec WILLIAM ARNOLD, University of Minnesota BARBARA BECK, Gradient Corporation YU-PING CHIN, The Ohio State University ZAID CHOWDHURY, Malcolm Pirnie DAVID ELLIS, DuPont Engineering TISSA ILLANGASEKARE, Colorado School of Mines PAUL JOHNSON, Arizona State University MOHSEN MEHRAN, Rubicon Engineering Corporation JAMES MERCER, Tetra Tech GEO KURT PENNEL, Tufts University ALAN RABIDEAU, State University of New York, Buffalo ALLEN SHAPIRO, U.S. Geological Survey LENNY SIEGEL, Center for Public Environmental Oversight WILLIAM WALSH, Pepper Hamilton LLP

3 Background For 30 years, remediation has eliminated or controlled acute risks; many hazardous waste sites with contaminated groundwater now closed. But, reaching unlimited use and unrestricted exposure (UU/UE) (i.e., drinking water standards or highest beneficial use) remains a significant challenge. A substantial number of sites exhibit attributes that make restoration unlikely for many decades. DoD has invested heavily in addressing legacy contamination in groundwater ($30 billion to date). Central theme of this report is how the nation should deal with sites where residual contamination remains above UU/UE levels

4 Stringfellow, CA, cerca million gallons of liquid hazardous waste released Site placed on NPL in 1983 Exposure pathways controlled Restoration will take ~ 500 yrs Future cost in excess of $200 million; Cost to Date > $500 M. State is RP. Have requested a TI Waiver for two of the four zones. ROD 5 in progress. Long-term management!

5 Statement of Task What is the size of the nation s hazardous waste problem? How much contamination can current technologies remove? What is the future of treatment technologies? Can mass removal be better correlated with sitespecific risk? How can better decisions be made?

6 Magnitude of the Problem Estimated the number of sites that have not yet reached closure Tabulated remediation costs expended to date Summarized costs estimated by others to reach closure as defined by regulatory program Estimated number of sites affecting public water supply sources Information listed above was not available for some programs DoD CERCLA (Superfund) RCRA UST DOE Other federal sites State Sites Sources: DoD & DOE annual reports to Congress; EPA website; RCRA and UST program managers; EPA (2004); USGS reports

7 Estimated Number of Sites/Facilities with Conditions not allowing for Closure and Costs to Complete Program/Agency Number of Facilities Number of Sites Estimated Cost to Complete ($B) DoD 4,329 $12.8 CERCLA 1,364 $16-23 RCRA 2,844 $32.4 UST 87,983 $11 DOE 3,650 $ Other Federal Sites >3,000 $15-22 State Sites >23,000 $5 TOTALS >126,000 $ See Table 2-6 in report

8 Chapter 2 Main Conclusions 126,000 sites that have not yet reached closure is likely an underestimate. Could not determine the total number of sites with residual contamination above levels allowing for UU/UE (must be > 126,000). More than 12,000 sites are complex. Estimated future cost of $ billion likely an underestimate. ~10% of Superfund sites affect drinking water supply sources. Nomenclature for site closure inconsistent between federal agencies, the states, and the private sector; confusing for public. More consistent and transparent terminology needed.

9 Analysis of 80 NPL-Delisted Groundwater Sites The Committee evaluated 80 contaminated groundwater sites, identified by EPA personnel, already deleted from the NPL. Site documents* were queried to consider several questions: What were the remedial goals? (e.g., MCLs or other) Contaminants of concern? Were MCLs met? If not, what levels were achieved? What remedial actions were used? Does monitoring continue? Were alternative strategies used? (e.g., TI Waivers) *SOURCES: CERCLIS, including 5-year reviews, fact sheets, Records of Decision, and close-out documents available on-line.

10 Did the 80 Delisted NPL Sites Reach MCLs? MCL Characterization Not a Groundwater Site MCL Achievement Unknown MCLs Achieved: Active Remedy, No LTM Remedial Objective Other Than Meeting MCLs 12 4 MCLs Achieved: Active Remedy, LTM MCLs Not Achieved: Deleted Based on Risk Assessment: LTM MCLs Achieved: No Active Remedy, No LTM MCLs Not Achieved: Deleted Based on Risk Assessment: No LTM 14 MCLs Not Achieved: LTM

11 Chapter 2 Main Conclusions 126,000 sites that have not yet reached closure is likely an underestimate. Could not determine the total number of sites with residual contamination above levels allowing for UU/UE (must be > 126,000). More than 12,000 sites are complex. Estimated future cost of $ billion likely an underestimate. ~10% of Superfund sites affect drinking water supply sources. Nomenclature for site closure inconsistent between federal agencies, the states, and the private sector; confusing for public. More consistent and transparent terminology needed.

12 Capabilities of Current Technologies An Update TECHNOLOGIES PERFORMANCE Thermal Treatment In Situ Chemical Oxidation Surfactant and Co-solvent Flushing In Situ Bioremediation Pump and Treat for hydraulic containment Physical Containment Permeable Reactive Barriers Monitored Natural Attenuation Combined Remedies Thermal Treatment In Situ Chemical Oxidation Surfactant Flushing Cosolvent Flushing In Situ Bioremediation <10X to X concentration and flux reduction; 95 to 99+ percent mass reduction of what is captured 55 to 90 percent mass reduction 65 to 90+ percent mass recovery 65 to 85 percent mass recovery 60 to 90 percent mass reduction

13 Chapter 4 Conclusions While significant reductions in mass, mass discharge, and concentration are reported, significant technical limitations persist that make achievement of MCLs throughout the aquifer unlikely at most complex groundwater sites for many decades. There are limited data upon which to base a scientifically supportable comparison of remedial technology performance. Since NRC (2005), only thermal and ISCO have undergone a thorough independent review Additional independent reviews needed on most promising technologies Research needed on how to combine existing or new remediation technologies to optimize mass removal and cost-effectiveness.

14 Implications of Contamination Remaining in Place Potential failure of engineering and institutional controls. Changes in toxicity and dose-response relationships (e.g., TCE) could result in site reopeners. New contaminants (e.g., NDMA/1,4-dioxane/nano) and exposure pathways (vapor intrusion) may emerge. Legal/economic issues like Natural Resource Damage and trespass may need to be addressed. Risks associated with well head treatment to prevent exposure. Economic impacts: property values may be negatively affected.

15 Technology Development to Support Long Term Management R&D investments have been unable to keep pace with the needs of practitioners conducting remediation. There is no national strategy for technology development to support long-term management of complex sites. It is not clear that the pertinent federal agencies will be capable of providing the funding and other support for R&D. A comprehensive assessment of future research needs, involving coordination between federal agencies, would allow research funding to be allocated in an efficient and targeted manner

16 Innovations to Support Long-Term Management Need research in several areas to meet the requirements of effective long-term management of complex sites Monitoring Sensors and other tools to assess vapor intrusion risks Molecular biological and isotope diagnostic tools precision treatment and to quantify the transformation capacity of subsurface Modeling More accurate estimates of time-to-reach-restoration goals Better accounting for back-diffusion and desorption Remediation Technologies Combined remedies may increase mass removal but no breakthrough technologies appear imminent

17 Better Decision Making: Overview Attainment of MCLs unlikely for decades or longer at large number of complex sites. Where costs are incurred with a diminishing reduction in concentration or risk, alternative strategies are needed. When the effectiveness of optimum site remediation reaches a point of diminishing returns prior to reaching cleanup goals, a Transition Assessment should be conducted. The Transition Assessment, which is like a Focused Feasibility Study, determines the appropriate end state for the site. EPA 2011 Road Map does not include this decision point (although some federal and state cleanups have used similar logic).

18 EPA Recognizes Alternate Approaches Are Needed for Sites Where Restoration is Unlikely EPA Roadmap July, 2011

19 Alternative Decision Making Process

20 Point of Diminishing Returns

21 Key Decision Points in the Transition Assessment Is a new remedy warranted and not precluded by a legal release? On case-by-case basis, is active or passive long-term management appropriate? Evaluate each alternative based on protectiveness ability to attain remedial action objectives implementability (including costs) more comprehensive risk analysis sustainability

22 Is a New Remedy Warranted? Only if no legal release from future liability applies or PRP offers to perform new remedy. Yes, under the following conditions: New technology satisfies remedy selection criteria and will meet RAOs in reasonable time frame. No, under the following conditions: RAOs cannot be achieved in a reasonable time frame use of realistic prediction models needed.

23 What are the Costs and Risks of Alternatives? Cost considerations should expand beyond typical net present value comparisons Appropriate net discount rate for current and future economic conditions Consideration of probabilistic cost models Risk analysis should expand beyond traditional methodologies Risk reduction over time Risk analysis if residual contamination unavoidable In-depth uncertainty analysis

24 Is Passive Long-Term Management Appropriate? If Active LTM not appropriate, evaluate Passive LTM. Decision should consider the following factors: Potential use of MNA time frame beyond 100 years Optimum monitoring program to ensure protectiveness and confirm degradation New diagnostic tools (e.g., CSIA, molecular biological tools, etc.) Effective institutional controls Acceptable community relations plan

25 Transition Assessment Other Factors to Consider Requires continued and transparent communication with community advisory groups (e.g., EPA CAGs, DoD RABs). Could utilize data and information from the five-year review process. MNA may eventually transition to natural attenuation without monitoring. Could eventually achieve UU/UE over longer time frames.

26 Summary of Key Points ~ 12,000 of the 126,000 remaining sites are complex and unlikely to reach UU/UE within years with current technologies. No major technological breakthroughs anticipated. When the active remedy reaches a point of diminishing returns prior to reaching cleanup goals, conduct Transition Assessment to accelerate decision for long-term management. Transition Assessment will require renewed community involvement. Cost savings anticipated from implementation of Transition Assessment but funding will still be needed for long-term management at these complex sites. Refocus R&D program to support optimum long-term management of complex sites.

27 Questions? Report available as pdf through National Academy Press website Hard copy available by February For further information, contact Dr. Laura Ehlers The webinar audio and pdf will be available on the WSTB website in a week: (