Remedial Investigation of Sediments in NJDEP s Site Remediation and Waste Management Program

Transcription

1 Remedial Investigation of Sediments in NJDEP s Site Remediation and Waste Management Program Nancy Hamill Bureau of Environmental Evaluation and Risk Assessment nancy.hamill@dep.nj.gov NJ Water Monitoring Council Meeting September 21,

2 Presentation Outline: Remedial Investigation of Sediment 1. Objectives of a Sediment Remedial Investigation 2. Regulatory Background 3. Sediment Sampling, Analysis, QA/QC Plan Design 4. Sediment Screening Criteria for Data Evaluation 5. Site-Specific Risk-Based Remediation Goals 2

3 1. Objectives of a Sediment Remedial Investigation To determine: if site contaminants have migrated from site to surface water body if contaminants are present above NJSWQS and sediment screening criteria Nature and extent (horizontal and vertical) of discharged contaminants if unacceptable risk to aquatic-dependent receptors If yes to all, remediate sediment to protective levels 3

4 2. Regulatory Background NO PROMULGATED SEDIMENT STANDARDS! Sediment remediation goals determined on caseby-case basis in accordance with: - Brownfield and Contaminated Site Remediation Act, N.J.S.A. 58:10B-1 et seq. - Spill Compensation and Control Act, 58: NJDEP Technical Requirements for Site Remediation N.J.A.C.7:26E, May Ecological Evaluation Technical Guidance, (EETG) February 2015 available at: 4

5 N.J.A.C.7:26E-1.16, 3.6 and Ecological Evaluation Technical Guidance Identify co-occurrence of: Environmentally Sensitive Natural Resources (ESNRs) on, adjacent, under influence of the site, Contaminants of Potential Ecological Concern (COPECs)- soil contaminant concentrations on-site are greater than ecological (sediment) screening criteria (ESC), and Contaminant Migration Pathways to ESNR (pipe outfall, ditches, swales, creeks, groundwater, direct discharge) 5

6 N.J.A.C.7:26E-4.8 and Ecological Evaluation Technical Guidance Remedial Investigation of Ecological Receptors: Delineate horizontal/vertical extent of siterelated contamination in all media, including surface water and sediment, to the NJSWQS and sediment screening criteria (background, if higher) Conduct an Ecological Risk Assessment to verify risk and determine site-specific risk-based sediment remediation goals Remediate to site specific remediation goal, sediment screening criteria, or background 6

7 Contaminant Migration Pathway Example LCP Superfund Site, Linden, NJ Hg process waste outfall pipe South Branch Creek Arthur Kill

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9 Contaminant Migration Pathway Example Lail Property Site, Paulsboro, NJ Direct disposal of PCBs into Mantua Creek Embayment 9

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11 3. Sediment Sampling, Analysis, QA/QC Plan Design musts Biased toward areas of suspected contamination/depositional areas to identify contaminant sources, gradients, hot spots Minimum of two depths (0-6 plus one other; if VOAs, 6-12 is first interval) Discrete samples (no composites) Total Organic Carbon, particle grain size Analyte lists: Priority Pollutant, Target Compound List Organics/Target Analyte List Metals from CERCLA, or SW846 List from RCRA; PCB congeners (USEPA Method 1668A/B) and Dioxin (USEPA Mehtod1613B) for sample subset 11

12 3. Sediment Sampling, Analysis, QA/QC Plan Design musts (con t) Co-located surface water samples close to sediment interface Background locations for sediment and surface water required - locations near study site with concurrent data collection - regional databases, e.g., Division of Water Monitoring and Standards Data must be validated; always report detection limits 12

13 4. Sediment Screening Criteria for Data Evaluation NJDEP Ecological Screening Criteria (ESC) Table, updated March 10,

14 Sediment Screening Values Foundation Datasets: 1. Freshwater Lowest Effects Levels (LEL) and Severe Effect Levels (SEL) Ontario Ministry of the Environment, Persaud, et al., Marine/Estuarine Effects Range-Low (ER-L) and Effects Range-Median (ER-M) Long et al., 1995 Large number of studies correlate adverse effects to sediment macroinvertebrates to bulk sediment contaminant concentrations LEL / ER-L: adverse impacts to sediment benthos in approximately 10% of studies SEL adverse impacts in approximately 95% of studies ER-M adverse impacts in approximately 50% of studies

15 Comparison of Sediment Data to Sediment Screening Criteria LEL/ER-L are the sediment screening criteria; SEL/ER-M are provided as frame of reference Screening criteria do not address bioaccumulation Persistent biomagnifying contaminants indicate potential wildlife risk; conduct additional site-specific evaluation Compare maximum and mean site-related data with sediment screening criteria Exceedences indicate potential for adverse ecological effects and more rigorous biological tests may be needed (sediment toxicity test, benthic community surveys, tissue analysis) Alternate or new sediment screening criteria (for contaminants w/o table values) can be proposed Contaminants w/o sediment screening criteria must be carried through the ecological risk assessment process

16 Comparison of Sediment Data to Sediment Screening Criteria (con t) If more than one sediment screening criteria, generally use most conservative Where analytical detection limits are higher than sediment screening criteria (e.g., PAHs), retain contaminant and use estimated concentrations for comparison Professional judgment for marginal exceedence of one or a few sediment screening criteria (e.g. Lead, PAHs in urban waterways); consider TOC where exceedance are borderline Sediment screening criteria used in SRWMP and throughout USEPA Region 2 site remediation programs PAHs, metals, pesticides, PCBs are top contaminant classes that exceed sediment criteria state-wide 16

17 5. Site-Specific Risk-Based Sediment Remediation Goals Sediment benthic macroinvertebrates: - Sediment toxicity tests for concentration-response models over concentration range - Equilibrium Partitioning Sediment Benchmarks (USEPA 2003, 2005, 2008) determine sediment concentration that provides pore water at aquatic toxicity benchmark; use sample-specific TOC/AVS Aquatic-dependent wildlife (birds, mammals): - Back-calculate from food chain models with site-specific prey tissue data Fish, larger macroinvertebrate: - Calculate using critical body residue (aka tissue residue effects levels) See Ecological Evaluation Technical Guidance for sample calculations 17

18 Receptors of Interest vs Prey Sampled

19 Example: Calculation of Site-Specific Sediment Remediation Goal for Piscivorous Wildlife 1. Calculate site-specific sediment-to-biota-accumulation factor, BSAF BSAF = C prey tissue / C sediment ; C tissue = C sediment x BSAF 2. Dose tot = (C prey tissue )(.9)(IR)/BW (e.g., great blue heron) Set desired dose equal to literature based NOAEL and substitute C sediment x BSAF for C tissue : 3. NOAEL = [C sediment x BSAF](.9)(IR)/BW 4. Solve for safe sediment concentration: C sediment, mg/kg = NOAEL x BW BSAF x.9 x IR

20 Program Needs Update Table! Increase use of sediment pore water sampling and comparison with water quality criteria for screening Increase use of Equilibrium Partitioning approach to determine site-specific sediment benchmarks Questions? 20