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Evaluation of Environmental Hazards at Sites with Contaminated Soil and Groundwater Roger Brewer, Ph. D Hawai‘i Department of Health Hazard Evaluation and Emergency Response (November 21, 2017) 1
HDOH 2017 Webinar Series Part 1: Systematic Planning and Site Investigation Design (TGM Section 3) Part 2: Decision Unit Designation (TGM Section 3) Part 3: Sampling Theory & DU Characterization (TGM Section 4) Part 4: Field Implementation of DU-MIS Methods (TGM Sections 5 & 8) Part 5: Laboratory Processing of MI Samples (TGM Section 4) Part 6: Environmental Hazard Evaluation (TGM Section 13). 2
Hawai′i DOH Guidance for the Investigation, Remediation and Management of Contaminated Properties 1. Testing Soil, Water and Air for Contamination: Technical Guidance Manual: http: //eha-web. doh. hawaii. gov/eha-cma/Org/HEER/ 2. Determining if There is a Problem: Evaluation of Environmental Hazards at Sites with Contaminated Soil and Groundwater: http: //eha-web. doh. hawaii. gov/eha-cma/Leaders/HEER/EALs Hawaii Edition: Environmental Action Levels (EALs) Tropical Pacific Edition: Environmental Screening Levels (ESLs) (excludes HDOH-specific standards, originally developed for use in CNMI & Guam) HEER Webinars: http: //eha-web. doh. hawaii. gov/eha-cma/Leaders/HEER/Webinar 3
There are three methods to gain knowledge: The first, reflection, is the noblest; The second, imitation, is the easiest; And the third, experience, is the bitterest. Confucius
Site Investigation Process Site Investigation Environmental Hazard Evaluation Advanced Evaluation of Targeted Hazards Response Action • Past use of unreliable, “discrete” sample data and excessively conservative action/screening levels added years to project completion; • Primary cause of “brownfields”; • Use of Systematic Planning and DU-MIS investigation methods ensures resulting data useful for final decision making; • Significantly expedites site characterization, remediation and closure.
DU-MIS WEBINARS #1 & #2: SYSTEMATIC PLANNING AND DECISION UNIT DESIGNATION (TGM SECTION 3) SURFACE EXPOSURE DU SOIL TRENCH WORKER DU SOIL 6
DU-MIS WEBINARS #3 & #5: DU CHARACTERIZATION & MULTI INCREMENT SAMPLING METHODS (TGM SECTION 4) Discrete Problems DU-MIS Solutions Brewer, R. , Peard, J. and M. Heskett (2017). A critical review of discrete soil sample reliability: • Part 1 – Field study results • Part 2—Implications Journal of Soil and Sediment Contamination. 7
Multi Increment Samples are not “Composites” Composited Discretes (saves $$$ but unreliable data) Composited MI Samples (a bad idea and not allowed) 8 8
DU-MIS WEBINAR #4: FIELD IMPLEMENTATION OF DUMIS INVESTIGATION METHODS (TGM SECTION 5) 9
Webinar Outline • Environmental Hazard Evaluation (EHE): – – – Site investigation process; Overview of potential environmental hazards; Environmental Action/Screening Levels (EALs/ESLs); Comparison to USEPA RSLs and other screening levels; Initial identification of potential environmental hazards; Advanced evaluation of environmental hazards; • EHE Reports; • Environmental Hazard Management Plans (EHMPs); • Use of discrete vs Multi Increment sample data in “risk assessments”.
Environmental Hazard Evaluation - Multiple Fields of Expertise Required • • Everyone: What are the DUs? Chemistry: What is it? Geology: Where is it? Physics: Where is it going? Toxicology: What can it do to me? Combined: What are the concerns? Attorneys: Who is going to pay? Directly incorporated into EHE guidance and EALs
Environmental Hazards Gross Contamination Human Health Terrestrial Habitats INDOOR AIR Vapor Intrusion Direct Exposure SOIL GAS Leaching Aquatic Habitats GROUNDWATER Gross Contamination Human Health Vapor Intrusion Drinking Water (toxicity)
Hawaii Groundwater Zones (Tier 1 Lookup Tables) Drinking Water Source Nondrinking Water Source Target SW= Acute SW= Chronic GW= DW A-1 A-2 GW= NDW B-1 B-2 “Tier 1” Soil EALs: • Contaminated soil at or near surface; • Over drinking water; • Unrestricted land use (e. g. residential).
EAL Sources Terrestrial Habitats (USEPA) Nuisance (MADEP) Human Health Vapor Intrusion (mod USEPA) Direct Exposure (site-specific) (USEPA RSLs) SOIL GAS Leaching: MADEP Aquatic Habitats (HI AWQC) INDOOR AIR GROUNDWATER Nuisance (Secondary MCL, MADEP) Human Health (mod USEPA) Vapor Intrusion (mod USEPA) Drinking Water (HI MCL)
PCE EALs 0. 46 µg/m 3 Residential, exposed soils, over drinking water Terrestrial Habitats - Gross Cont. 170 mg/kg For Example Only Check for Updates Aquatic Habitats 53 µg/L Human Health INDOOR AIR Vapors to IA 0. 098 mg/kg Direct Exposure 1. 1 mg/kg SOIL GAS Leaching: 0. 64 mg/kg 920 mg/m 3 GROUNDWATER Vapors to IA 190 µg/L Gross Cont. 170 µg/L Human Health Drinking Water 5 µg/L
Environmental Action Levels (EALs) • EALs for 150+ common contaminants; – Volume 1: Tier 1 Final EALs; – Volume 2: Technical background and detailed action levels. • Easy-to-use, Excel-based “EAL Surfer” electronic lookup tables (EAL Surfer Apps being developed): – Select site scenario; – Select chemical by name or CAS #; – Input site data; – Automatically identifies potential environmental hazards; – Summary report generated; • Complete investigation and screen out low-risk areas; • No significant hazards if concentrations <EALs; • Additional evaluation +/- remediation required if EALs exceeded.
Chemical Partitioning in the Environment Versus Potential Environmental Hazards vapors Sorbed NAPL Dissolved Vapor leachate Total Soil Conc. = Sorbed + Dissolved + Vapor + “Free Product” Primary Chemical-Specific Modeling Factors: Henry’s Law Constant (Vapor Conc. /Dissolved Conc. ); Sorption Coefficient (Sorbed Conc. /Dissolved Conc. ); Solubility. Assumed Soil Properties: moist soil, low organic carbon, etc.
Assumed Contaminant Partitioning in Soil (based on default USEPA RSL soil type) Sorbed Dissolved Vapor Eat Drink Breath Benzene Vinyl Chloride Ba. P • Chemical partitioning in soil directly tied to exposure pathway and risk; • Action levels reflect chemical fate and transport + toxicity.
Contaminant Group vs Primary Environmental Concern Leaching *Direct Exposure Chemical Family Light petroleum, solvents, pesticides, inorganic salts Carcinogen PAHs, PCBs, metals, etc. Vapor Emissions Carcinogenic VOCs Terrestrial Ecotoxicity Gross Contamination Noncarcinogenic metals & pesticides Heavy TPH, noncarcinogenic metals & solvents, phenols, etc. *Soil ingestion, inhalation of outdoor vapors and dermal contact
Example: Former Fuel Tank Farm (TPH+BTEX) • TPH data assessed in same manner as individual compounds; • Toxicity factors and action levels for soil, water & air available for all potential concerns; • Often drives direct exposure risk over BTEX (see HEER webinars); • Groundwater metabolites assumed similar toxicity to parent hydrocarbons; • Remediation and/or long-term management often driven by gross contamination concerns (e. g. , short-term vapor emissions during construction, sheens, etc. ). Brewer, R. , Nagashima, J. , Kelley, M. and M. Rigby, 2013, Risk-Based Evaluation of Total Petroleum Hydrocarbons in Vapor Intrusion Studies: International Journal of Environmental Research and Public Health, Volume 10, pp 2441 -2467. http: //www. mdpi. com/1660 -4601/10/6/2441/21
Identification of Potential Environmental Concerns (e. g. , TPHg and BTEX) Gross Contamination (soil & gw) Vapor Intrusion (soil gas) Leaching (soil) Aquatic Toxicity (GW) Direct Exposure (soil) Hypothetical Site. For Example Only! • Identified Potential Environmental Concerns for TPH (including metabolites): • Gross Contamination: TPH soil and groundwater exceeds gross contamination screening levels (heavy contamination of soil, free product on groundwater); • Direct Exposure: TPH soil data (MIS/ISM) exceeds direct-exposure screening levels; • Vapor Intrusion: TPH soil vapor exceeds vapor intrusion screening levels; • Leaching Concerns: TPH soil data (MIS/ISM) exceeds leaching screening levels • Aquatic Toxicity: TPH groundwater data exceeds aquatic toxicity screening levels.
Site-Specific CSM and Considerations Exposure Pathways Complete? Vapors intruding buildings? Exposed soil? Leaching? Groundwater Impacted? Stream Discharges to aquatic habitats? ? Wells Impacted?
Partial Remediation and Long-Term Management -Environmental Hazard Management Plans (EHMPs)Gross Contamination (soil & gw) Vapor Intrusion (soil gas) Leaching (soil) Aquatic Toxicity (GW) Direct Exposure (soil) Hypothetical Site. For Example Only! • Example Remediation and Redevelopment Design: • Active remediation of Gross Contamination and highest-risk Vapor Intrusion and Direct Exposure risk areas; • Passive vapor barrier to future buildings as added measure of protection; • Monitoring of groundwater confirms dissolved-phase plume not migrating offsite above levels of potential concern; • Long-term management of soil & gw required for subsurface activities (EHMP).
Calculation of Toxicity-Based “Direct Exposure” Action Levels 1. Risk = Average Daily Dose x Toxicity 2. ADD = Media Concentration x Exposure Rate Default USEPA Exposure Rates: Inhalation: 10 -20 m 3/day Soil Ingestion: 100 -200 mg/day Drinking Water: 1 -2 L/day 3. Risk-Based Media Conc. = Target Risk : Exposure Rate Toxicity 4. Risk-Based Media Conc. = Max Ave Daily Dose : Exposure Rate
Direct Exposure Action Levels (Water, Soil, Air, etc. ) “Dose Makes The Poison” 1 No Adverse Effect Average Daily Dose Chronic Health Effect Water A few gallons at once Acute Hyponatremia Aspirin 81 mg/day (3 drops/day) G/I tract 2 TPHg 0. 90 mg/day (1 drop/month) Multiple 2 PCBs 0. 0002 mg/day (1 mm grain/20 yrs) Multiple Chemical 1. For example only (safe dose varies with route of exposure, target cancer risk and noncancer hazard, child vs adult, etc. ). 2. Child (15 kg), chronic exposure over 6 years (noncancer HQ = 1. 0). Toxicity factors typically includes 10 -100+ fold safety factor. MTBE maximum daily dose = 28 µg/day Assumed water consumption = 2 L/day Drinking water action level = 14 µg/L
PCE EALs 0. 46 µg/m 3 Residential, exposed soils, over drinking water (10 -6 ECR) Inhalation: 10 -20 m 3/day Soil Ingestion: 100 -200 mg/day Drinking Water: 1 -2 L/day Human Health INDOOR AIR Direct Exposure 1. 1 mg/kg (10 -6 ECR) Alternative Soil & Air Commercial/Industrial DE Action Levels Also Provided SOIL GROUNDWATER For Example Only Check for Updates Human Health PCE MCL: Based on 10 -5 ECR Drinking Water 5 µg/L
Vapor Intrusion Hazards (see separate webinars) (example PCE action levels) Site Investigation Steps Residence Tropical “SSAF” =0. 0005 Indoor Air (0. 46 µg/m 3) USEPA VI Models Soil Gas + Field Data (920 µg/m 3) +/- Step 3: IA data Step 2: SV data Soil 0. 098 mg/kg Groundwater (190 µg/L) Step 1: Soil & G W data
PCE EALs 0. 46 µg/m 3 Residential, exposed soils, over drinking water Alternative C/I VI Action Levels Also Provided For Example Only Check for Updates Human Health INDOOR AIR Vapors to IA 0. 098 mg/kg Direct Exposure 1. 1 mg/kg SOIL GAS 920 mg/m 3 GROUNDWATER Human Health Vapors to IA 190 µg/L Drinking Water 5 µg/L
Step 3. Indoor Air Sampling (Caution!) • Indoor sources of VOCs (e. g. , petroleum & solvents); • Always include soil vapor data (tie to subsurface source? ); • “Large Volume Purge” subslab vapor data preferred (TGM Section 7; see HEER webinar webpage)
Hawaii Vapor Intrusion Action Levels Not Adequately Conservative for Colder Climate Zones VIR Region B 1 (Coastal) Moderate Risk (SSAF = 0. 002) VIR Region C (Mediterranean) Lower Risk (SSAF = 0. 008) VIR Region A (Cold, +Alaska) Highest Risk (SSAF 0. 003) VIR Region B 2 (Warm) Moderate Risk (SSAF = 0. 002) VIR Region D (+Hawaii) Lowest Risk (SSAF = 0. 0005) Brewer, R. , Nagashima, J. , Rigby, M. , Schmidt, M. and O'Neill, H. (2014), Estimation of Generic Subslab Attenuation Factors for Vapor Intrusion Investigations. Groundwater Monitoring & Remediation, 34: 79– 92. http: //onlinelibrary. wiley. com/doi/10. 1111/gwmr. 12086/full
USEPA “Empirical” Database Attenuation Factors Invalid • Vapor attenuation factors estimated for hundreds of homes; • Based on single, one-liter subslab vapor samples; 95% UCL • Only valid if uniform vapor SSAF= 0. 03 plume; • Vapor plumes heterogeneous; • Database can’t be “fixed” by statistical analysis; • Calculated attenuation factors IA: Random Subslab Noise? not “conservative, ” they are technically invalid. Frequency Median HEER Vapor Intrusion Webinars: http: //eha-web. doh. hawaii. gov/eha-cma/Leaders/HEER/Webinar
Leaching of Contaminants from Soil 1. Concentration in soil Csoil = Cgw x [(6207 x H) + (0. 166 x Koc)] 2. Concentration in source leachate x x 3. Concentration in leachate at groundwater interface groundwater plume 4. Concentration in groundwater
PCE EALs 0. 46 µg/m 3 Residential, exposed soils, over drinking water Human Health INDOOR AIR Vapors to IA 0. 098 mg/kg Direct Exposure 1. 1 mg/kg For Example Only Check for Updates SOIL GAS Leaching: 0. 64 mg/kg 920 mg/m 3 GROUNDWATER Vapors to IA 190 µg/L Human Health Drinking Water 5 µg/L
Lab-Based Soil Leaching Tests Sorbed Dissolved Vapor leachate • SESOIL leaching model over predicts contaminant desorption and concentration in leachate; • Synthetic Precipitation Leaching Procedure (SPLP) batch more accurately estimates Kd and leaching hazards (see HDOH guidance and spreadsheet model); – 100 grams soil mixed in 2 liter water; – Kd based on original total mass vs mass dissolved; • Future: “LEAF” soil column leaching tests?
Groundwater Discharges to Surface Water spring Aquatic toxicity action levels should be met a point of groundwater discharge (excluding mixing and dilution)
Groundwater Discharges to Surface Water Freshwater Springs Along Shoreline Aquatic toxicity action levels should be met a point of groundwater discharge (excluding mixing and dilution)
PCE EALs 0. 46 µg/m 3 Residential, exposed soils, over drinking water Terrestrial Habitats Human Health Aquatic Habitats C: 53 µg/L A: 1, 800µg/L Vapors to IA 0. 098 mg/kg Direct Exposure 1. 1 mg/kg (site specific) For Example Only Check for Updates INDOOR AIR SOIL GAS Leaching: 0. 64 mg/kg 920 mg/m 3 GROUNDWATER Vapors to IA 190 µg/L Human Health Drinking Water 5 µg/L
Gross Contamination Hazards Function of short-term exposure risk, odor threshold, solubility, sheens and visible staining/contamination etc. • Short-term vapor emissions; • Explosive vapors; • Odors & nuisance; • Potentially mobile free product; • Staining or visible debris/contamination; • Interference with future development; • Include in site-specific EHMP if left in place.
PCE EALs 0. 46 µg/m 3 Residential, exposed soils, over drinking water Terrestrial Habitats Gross Cont. 170 mg/kg Human Health Aquatic Habitats 53 µg/L Vapors to IA 0. 098 mg/kg Direct Exposure 1. 1 mg/kg (site specific) For Example Only Check for Updates INDOOR AIR SOIL GAS Leaching: 0. 64 mg/kg 920 mg/m 3 GROUNDWATER Vapors to IA 190 µg/L Gross Cont. 170 µg/L Human Health Drinking Water 5 µg/L
EHE Report (separate or part of site investigation report) • Site Background • Summary of investigations • Comparison of site data to action levels • EHE: Identification of potential hazards • Advanced evaluation of targeted hazards • Conclusions & Recommendations • Summarize findings • Addition site investigation? • Advanced evaluation of targeted hazards? • Prepare remedial action plan? • Prepare EHMP? • No further action required?
Environmental Hazard Management Plans (long-term management of residual contamination) • Same information as in EHE • Appendix to closure report (simple) or separate document (complicated) • Include to-scale maps of affected areas • Summarize site restrictions & management needs • soil & groundwater management • caps, vapor barrier systems, etc. • land-use restrictions, etc. • Consider EHMP in budget for future development & maintenance: • Construction EHMP • Post-Construction EHMP (include upsdated EHE)
EAL Target Risk and “Site-Specific” Risk Assessment Considerations USEPA 1991 (OSWER DIRECTIVE 9355. 0 -30): “For sites where the cumulative site risk to an individual based on reasonable maximum exposure… is below 10 -4, (remedial) action generally is not warranted. ” USEPA 1994 (National Contingency Plan): “In cases (which) result in a cumulative risk in excess of 10 -4, (technical limitations, uncertainty and other pertinent information) may be considered when determining … (final) cleanup level(s). ”
Risk vs Remediation USEPA 2017 (Removal Management Levels): “Where the cumulative carcinogenic site risk… is less than 10 -4 and the non-carcinogenic (index) is less than 1, action generally is not warranted. ” *Ensure No Further Cumulative Risk Investigation Limits Not Remediation Warranted Exceeded Warranted Cancer Risk: 0 Noncancer Hazard: 0 … 10 -4 10 -6 1. 0 0. 2 Increasing Health Risk ……. . *Other considerations include remediation feasibility, exposure scenario, target COPCs, confidence in toxicity factors, etc.
Cumulative Risk vs EAL Target Risk Cumulative Risk = “Chemical A Risk” + “Chemical B Risk” + “Chemical C Risk” + “Chemical D Risk”. . . • • • Individual chemicals might not pose risk but in combination potentially significant risk present; Target risk for individual chemical typically set lower than maximum acceptable; Additional consideration of cumulative risk required if number of chemicals with similar health effects present exceeds number assumed in action level target risk (rare; see Appendix 1 Table J Target Health Effects).
Example PCE Target Risk Versus Selection of Soil Direct Exposure Action Level (residential) Soil Action Level 110 mg/kg selected as final action level 10 -5 10 -6 11 mg/kg 1. 1 mg/kg Noncancer Hazard Quotient Target Risk Range Excess Cancer Risk 10 -4 *Soil Action Level 1. 0 87 mg/kg 0. 2 17 mg/kg 0. 1 8. 7 mg/kg Considerations: Volatile chemical, inhalation risk, high confidence in cancer studies, often present with other carcinogenic VOCs.
Example Arsenic Target Risk Versus Selection of Soil Direct Exposure Action Level (residential) 10 -5 10 -6 4. 1 mg/kg 0. 41 mg/kg Noncancer Hazard Quotient *Soil Action Level selected as final action level Target Risk Range Soil Action Level 41 mg/kg Target Risk Range Excess Cancer Risk 10 -4 1. 0 23 mg/kg 0. 2 0. 1 4. 6 mg/kg 2. 3 mg/kg Considerations: Natural background, higher confidence in noncancer studies, primary risk driver if present, *bioaccessible arsenic.
Chemical-Specific Target Risks (App 1, Sect 4. 2. 2) Chemical Target Risk Rationale *Default (most VOCs) ECR = 10 -6 HQ = 0. 2 Conservative consideration of cumulative risk Ethylbenzene, Naphthalene, ECR = 10 -5 Heptachlor, Heptachlor Epoxide HQ = 0. 2 Higher confidence in noncancer toxicity factors PAHs ECR = 10 -5 HQ = 0. 2 Anthropogenic background, (Ba. P ECR = 5 x 10 -5, focus on nc) Chlordane, PCBs ECR = 10 -5 HQ = 1. 0 Focus on noncancer hazard, primary risk driver Aldrin, Dieldrin, ECR = 10 -4 HQ = 0. 5 Focus on noncancer hazard, cooccur, primary risk drivers Arsenic, TEQ Dioxins, Cr. VI ECR = 10 -4 HQ = 1. 0 Focus on nc hazard, primary risk drivers, nat background TPH HQ = 1. 0 Primary noncancer risk driver Lead separate model Reduced target blood level, anthropogenic background. *Tapwater default ECR = 10 -6 HQ = 1. 0 (see Appendix 1 for variances).
HDOH EALs versus Cal. EPA ESLs and USEPA RSLs GW Soil Environment Hazard 1 HDOH 2 Cal. EPA EALs ESLs USEPA RSLs Direct Exposure X X X Vapor Intrusion X X - Leaching X X - Gross Contamination X X - DW Toxicity X X X Vapor Intrusion X X - Aquatic Habitats X X - Gross Contamination X X - 1. HDOH: Vapor intrusion action levels reflect tropical climate. 2. Cal. EPA: Vapor intrusion screening levels reflect moderate climate with warm summers and short, cold winters.
HDOH EALs versus Cal. EPA ESLs and USEPA RSLs Risk Category Excess Cancer Risk Noncancer Hazard Quotient 1 HDOH 2 Cal. EPA 3 USEPA EALs 10 -4 to 10 -6 ESLs RSLs 10 -6 1. 0 0. 1 and 1. 0 0. 2 to 1. 0 1. HDOH: Chemical specific considerations made for both target cancer risk and noncancer hazard (default 10 -6 ECR and 0. 2 noncancer HQ; see App 1, Section 4. 2. 2). 2. Cal. EPA: Most conservative target cancer risk and least conservative target noncancer hazard applied to all chemicals (ignores potential cumulative risk). 3. USEPA: Most conservative target cancer risk for all chemicals. Two sets of noncancer action levels presented based on both most conservative and least conservative target noncancer hazard
Last Notes… • Don’t I need to compare the EALs to a 95% UCL? • Only if replicate MI samples RSD >50% (getting rare); • 95% UCL applied to discrete sample data in attempt to address distributional heterogeneity (aka “variability); • Field representativeness of single data set unknown; • Sampling theory for particulate matter not considered; • “Outlier” data inappropriately excluded; • Discrete sample data not allowed for final decision making; • Sampling theory used to address distributional heterogeneity under Multi Increment sampling methods; • Don’t I need to look for acute “hot spots” within DUs with discrete samples? Refer to recording of DU-MIS Webinar #3 (Sampling Theory) 52
How Do I Assess “Acute Risk”? 20’ x 20’ front yard Hypothetical Regulatory Requirement “No single discrete sample in upper 3” of soil shall exceed 400 mg/kg lead (short-term risk). ” Total Soil Mass = 3, 000 kg What soil mass does 400 mg/kg apply to? What is the Decision Unit? • 100 g? (discrete sample mass; 30, 000 potential DUs); • 1 gram? (standard laboratory subsample mass; 3, 000 potential DUs); • 200 mg? (default child soil ingestion rate; 15, 000 potential DUs); • 10 grams? (pica child soil ingestion rate; 300, 000 potential DUs); • Reality: • “Acute” soil screening levels not available for most contaminants; • Not feasible to negate presence of small masses of “acutely toxic” soil with any degree of confidence based on either discrete or MI soil sample data; • Scrape or cap site if realistic, exposure risk suspected (e. g. , lead paint chips); • Evaluate chronic risk with Multi Increment (MI) samples; 53 • Assume theoretical acute risk acceptable if long-term, chronic risk acceptable.
Summary • Environmental Hazard Evaluation (EHE): – Use of reasonably conservative, HDOH Environmental Action/Screening Levels (EALs/ESLs) expedites the risk assessment & remediation process; – Comprehensive action levels ensures that common, potential environmental hazards are not overlooked; – Cumulative risk and commonly accepted adjustments for target risks incorporated; – Advanced, site-specific evaluation for identified, potential hazards as necessary (rarely time/cost beneficial for Direct Exposure and Vapor Intrusion); • Results and recommendations summarized in EHE report; • EHMP prepared for remaining contamination (e. g. , construction, final closure, etc. ).
Questions? Discrete Sample Data + Excessively Conservative Screening Levels and “Site. Specific” Risk Assessments DU-MIS Data + Comprehensive, Reasonably Conservative EALs/ESLs and EHEs Faster, more reliable and cheaper in the long run 55