Porewater:  NJDEP Site Remediation Program regulatory perspective

SETAC - Hudson Delaware Chapter2015 Fall Workshop

October 7, 2015 Princeton, NJ

Greg Neumann - NJDEP

NJDEP Regulations

o NJDEP Technical Requirements for Site Remediation – NJAC 7:26E

Minimum regulatory requirements

o Ecological Evaluation Technical Guidance (February, 2015)

Ecological Evaluation Technical Guidance

Sections relevant to Porewater:o Section 5 Ecological Evaluation (EE)o Section 6 Ecological Risk Assessment

o Risk Characterization – quantify ecological risko Section 6.2.2.3 Sediment Porewater samplingo Section 6.4.6 PAHs – USEPA White Paper

(2009) SPME – 3 Tiered approach assess risk to benthic community.

o Appendix F Sediment Porewater Sampling Techniques

Porewater – Why?

Bioavailability

Arsenic

Arsenic Sed. Chemistry

Pore Water 100 ppb

45 ppm

45 ppm

340 ppb

o Bulk sediment chemistry results are not accurate predictors of sediment toxicity. Measure solid phase.

o Porewater concentrations more accurately predict benthic toxicity by measuring bioavailable fraction

o Site-specific sediment characteristics influence porewater concentrations (i.e. TOC, AVS, DOC, pH, Eh)

o Porewater results represent the bioavailable fraction of sediment contamination.

Bioavailability/Porewater

Porewater Samplingo Most appropriate during risk

characterization stage of ERAo Predominately used to evaluate risk to

benthic community.o GW Surface Water dischargeso Utilized in a Weight of Evidence approach

o Sediment toxicity testso Tissue sampling PBTs (PCB/DDT)

Porewater Samplingo Post-Remedial Monitoring

o Conventional and Amended Sediment Caps

o In-situ Treatment – activated carbon, apatite, organophylic clay, ZVI

o Remedies effective due to sorptive capacity – longevity

oGW remedy to protect SWo Baseline Conditions

Porewater Sampling Devices

Trident Probe Ultra Seep System

Piezometers Peeper

Push-Point Sampler

Rigid polyethylene

Diffusion Gradient Thin Films

Porewater SamplingConsiderations

o Sampling medium must be capable of detecting site Contaminants Of Concern

o Deployment time – must be able to achieve equilibrium

o Performance Reference Compoundso In-situ vs. Ex-Situo Data generated must be in line with Data

Quality Objectives.

Future Needso Current guidance primarily focuses on the

sampling techniques and design factors related to pore water sampling (characterization of risk)

o Future guidance is needed that clearly documents how porewater sampling results can be used to develop sediment clean-up goals.

o Much of the porewater info. is housed in literature/research based publications. This info. has to be brought forward and presented in more primary based guidance documents (EPA/SETAC/ITRC Publications)

Future Needs

o Standardization of sampling devices and protocols.

o Additional studies to link PW results to benthic toxicity.

NJDEP & Porewater

o NJDEP Regulations and Guidance support the use of Porewater sampling!!

o Porewater sampling can effectively be used to better quantify ecologic risk.

o Porewater sampling can be employed during the risk characterization stage of an ERA and during Post-Remedial Monitoring.

o Porewater sampling can represent an important line of evidence in an overall weight of evidence approach.

Porewater

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