1 ITRC s Use of Risk Assessment in Management

1 ITRC’s Use of Risk Assessment in Management of Contaminated Sites (RISK-2, 2008) ITRC Risk-2 Training Course Supplement: Use of Risk Assessment in Management of Contaminated Sites Five Retrospective Case Studies

2 Module 2 Learning Objectives u Risk assessment (RA) & Risk management (RM) is a balancing act among: • • • “Players” Communication Data Iteration Variation

3 Module 2 Learning Objectives Risk assessment (RA) & Risk management (RM) is a balancing act among: Time Money Stakeholders Cleanup Data analysis Certainty Acceptable

4 Case Study Features u Actual sites retrospectively evaluated • Site background • Sampling and data use • Risk-related information u “Simple” sites selected to elucidate key variables • Soil ingestion • Shallow soil contamination • One to few chemicals of concern u NOT reanalysis or effort to “fix” these cases

5 Five Case Study Sites Evergreen, WA LUST Site, WI Whitebridge, CA Grand Street, NJ Spring Valley, WDC

6 Case Study 1 – Evergreen, WA u Army to redevelop firing range for military housing u Active military base Berm

7 Triad Approach Investigation u Real time field data … for Risk Assessment(!) u Portable X-Ray Fluorescence (XRF) u Determined extent of area sampled u Validated by 10% laboratory analyses

8 Lead Characterization Goals 50 mg/kg XRF lead detection limit WA screening level for ecological assessment 250 mg/kg WA human health screening level IEUBK output 400 mg/kg USEPA Region 9 screening level (PRG) 1, 000 mg/kg Hazardous waste screening level

9 Cleanup Goal u No site-specific risk assessment Impact Berm Evergreen Avenue u Impacted berm area only remedial action candidate Pyros Side Berm u Screening level = Cleanup goal Gun Gun Command Island (Not Drawn to Scale)

10 Statistical Criteria for Remedial Success u No excavation area with Pb sample >500 mg/kg u Entire site 95% UCL Pb < 250 mg/kg u ≤ 10% of samples Pb > 250 mg/kg u Entire site meet criteria for all contaminants

11 Summary 1 – Evergreen, WA u Triad Approach + Field data in Risk Assessment u Background [Pb] < Screening level u RA/RM Balancing Act: Limited time/More remedial effort vs. higher screening and cleanup level u Screening level = Cleanup Goal u Statistical approach to remedial criteria

12 Case Study 2 – Whitebridge, CA u u u Former commercial orchard (1930’s to 1980’s) proposed for residential redevelopment Eight COPCs: Lead, arsenic, dieldrin, DDT, DDE, endosulfan, sulfate, and endrin aldehyde. Developer wanted minimal soil removal to meet septic system requirements

13 Risk Assessment – Three Tiers

14 Summary 2 – Whitebridge, CA u RA/RM Balancing Act: Minimal soil removal vs. Risk analysis effort u 3 Tiered Iterative approach: • Preliminary & Site-specific risk assessment Risk Potential • Probabilistic modeling Reduced areas of concern & COCs u Clear communication of goals u Contaminated soil Roadway fill Onsite deed-restricted containment cell

15 Case Study 3 – LUST site, WI u Operating gasoline station u Release discovered during tank system replacement u Benzene primary COC with 13 mg/kg soil

16 Case Study 3 – LUST Site, WI u Benzene concentration exceeded Direct-contact (WI ) [Inhalation & ingestion] (USEPA SSG calculator) u “Hot spot” beneath dispenser Barrier cover (2 ft clean soil) u Institutional control to prevent direct-contact exposure “Detailed closure letter”

17 Summary 3 – LUST Site, WI u Soil sampling • Contamination extent and magnitude • Not systematic • Not supportive of risk assessment u RA/RM Balancing Act: Limited soil data vs. Desire for case closure u Single “Hot spot” drove management u LUST sites Risk Assessment

18 Case Study 4 – Spring Valley, DC u u u Formerly Utilized Defense Site (FUDS), during World War I Chemical warfare research and testing: mustard, lewisite agents, adamsite, irritants, and smoke Long established residents

19 Phase I Investigation u 1921: Area restored, owners reclaim property, redeveloped u 1993: Buried ordinance found u 1993 to 1995: Phase I: ID areas of concern Biased grab samples Background samples 12. 6 mg/kg (95 th percentile) u Arsenic (As) contaminant of potential concern (COPC)

20 Phase II: Uncertainty Management with Different Sampling Strategies Adjacent Area Active Area House

21 Numerical Criteria Arsenic Concentration Source and Use 0. 43 mg/kg EPA Region 3 residential risk-based concentration; Initial site screening; ; 10 -6 cancer risk 12. 6 mg/kg Site-specific statistical ‘background. ’ Screening level triggering additional sampling 20 mg/kg Risk-informed management goal Soil removal 43 mg/kg Remedial goal with home owner approval to preserve landscape features; 10 -4 cancer risk

22 Summary 4 – Spring Valley, DC u Existing residents u Background [As] u Different sampling strategies for management of different levels of uncertainty u RA/RM Balancing Act: Screening level Among “Players”, Communication, Risk assessment, and Risk management

23 Case Study 5 – Grand Street, NJ u > 50 years Mercury gas-lamp & connector-switch production Peter Cooper-Hewitt, 1902 “ the economy of operation [of a mercury gas light in contrast to an ordinary incandescent lamp] will much more than compensate for the somewhat unnatural colour given to illuminated objects. "

24 Exposure to Building Residents u 5 -story former industrial building 16 residences/studios (1993 -1995) u 15/16 conversions completed prior to ID of site-wide Hg contamination in flooring, porous wood, and brick. u Residents relocated (1996) u Urine analysis found 20 residents (inc. 5 children) with Hg levels of concern for neuro- and hepatotoxicity u Superfund site

25 Different Criteria EPA Region II NJDEP Site Remediation Baseline HH RA Required (Human Health Risk Assessment) Yes No 1 x 10 -4 - 1 x 10 -6 1 1 Yes No Typically 0 -2’ for residential “to a clean zone” regardless of depth Discrete vs. Composite Surficial Sampling Both Discrete only Grid or Biased Sampling Either (Gridded) Biased only Risk Range - Carcinogen Hazard Index - Noncarcinogen Surface vs. Subsurface Distinction Depth of Delineation (RDC)

26 Sampling, Goals, and Remediation u Surficial soil cleanup goal = 23 mg/kg Hg (2003) Soil ingestion + protective of inhalation u Subsurface soil cleanup goal = 520 mg/kg Hg (2004) Protective of utility workers u Remediation = demolition, excavation, and off-site disposal of contaminated soil and building debris

27 Summary 5 – Grand Street, NJ u RA/RM Balancing Act: Two regulatory authorities (USEPA and NJDEP ) Two set of criteria u Acute hazard u Remediation = demolition u Redevelopment

28 Summary Table 1 – Site Information Site Whitebridge, CA COC Pesticides Acres Former Land Use Future Land Use 184 Commercial orchard Residential (future) LUST Site, WI Benzene 0. 70 Gasoline station (currently operating) Industrial (ongoing) Grand Street, NJ Mercury 0. 34 Hg gas-lamp + switch manufacture Residential (current) Lead 4 US Army firing range Residential (future) Evergreen, WA Spring Valley, DC Arsenic USDOD chemical 0. 25 warfare testing Residential (current)

29 Summary Table 2 – Risk Assessment Site Risk Assessment Whitebridge, CA • 3 Tiers (Preliminary, Deterministic, and Probabilistic) LUST Site, WI • 1 Tier (No site-specific RA. Screening Level = Cleanup Level) • State & USEPA risk-based screening values. Grand Street, • 2 Tiers • Both USEPA R 2 and NJDEP criteria NJ Evergreen, WA • 1 Tier (No site-specific RA. Screening Level = Cleanup Level. ) • Triad. Statistical criteria. Spring Valley, • 2 Tiers • Integrated into risk management. Community participation. DC

30 Summary Table 3 – Risk Management Site Risk Management Whitebridge, CA Developer + PRA Limited soil excavation (and costs) LUST Site, WI Hot spot beneath dispenser closed in place with barrier. Detailed closure letter with land-use limitation Grand Street, Demolition, excavation and off-site disposal. New residential development planned. NJ Evergreen, WA Quick reuse desire balanced with soil management. Soil excavation balanced by RA Spring Valley, DC Integrated into risk assessment. Community participation

31 Conclusions u Risk assessment and risk management balancing act • • • Players Iteration Data Communication Variation u Programmatic and Technical rationale Variation u Transparency is important “Everyone is on board!!”

32 Thank You u Links to Additional Resources at • http: //www. clu-in. org/conf/itrc/ risk 2/resource. cfm u ITRC Risk Team’s Website • http: //www. itrcweb. org/Risk u ITRC Risk Team’s Documents • http: //www. itrcweb. org/ guidancedocument. asp? TID=44

33 ITRC Disclaimer and Copyright Although the information in this ITRC training is believed to be reliable and accurate, the training and all material set forth within are provided without warranties of any kind, either express or implied, including but not limited to warranties of the accuracy, currency, or completeness of information contained in the training or the suitability of the information contained in the training for any particular purpose. ITRC recommends consulting applicable standards, laws, regulations, suppliers of materials, and material safety data sheets for information concerning safety and health risks and precautions and compliance with then-applicable laws and regulations. ECOS, ERIS, and ITRC shall not be liable for any direct, incidental, special, consequential, or punitive damages arising out of the use of any information, apparatus, method, or process discussed in ITRC training, including claims for damages arising out of any conflict between this the training and any laws, regulations, and/or ordinances. ECOS, ERIS, and ITRC do not endorse or recommend the use of, nor do they attempt to determine the merits of, any specific technology or technology provider through ITRC training or publication of guidance documents or any other ITRC document. Copyright 2007 Interstate Technology & Regulatory Council, 444 North Capitol Street, NW, Suite 445, Washington, DC 20001