Ecological Evaluation Technical Guidance - State of New Jersey

Twelve dioxin-like PCB congeners have been identified by the World HealthOrganization (WHO) and assigned Toxic Equivalency Factors (TEF) becausethey produce biological effects similar to 2,3,7,8-TCDD with varying potenciesand generally act together in an additive fashion. The term “2,3,7,8-TCDD”refers to the single compound, 2,3,7,8-tetrachloro dibenzo-p-dioxin, the mosttoxic form of this class of compounds. Refer to Section 6.4.7 for management ofPCB congener data via the Toxic Equivalency (TEQ) approach.It is important for the field sampling and analysis plan to specify whetherenvironmental media and biota will be analyzed for individual PCB Aroclors,homolog groups, 209 PCB congeners, or the 12 dioxin-like PCB congeners. Inmost cases, sampling conducted for the EE during the SI should be focused onindividual PCB Aroclor analysis. Unless there is clear indication that morerigorous analyses are required, such as for a site known to have elevated PCBs inESNRs, this approach is reasonable because analyzing samples for Aroclors isless time-consuming and less costly than conducting analyses for the homologs orthe congeners (Bernhard and Petron, 2001). For screening purposes, individualPCB Aroclors may be an appropriate level of analysis, particularly where thereare time and financial constraints, and where the size of the potentially impactedarea is relatively small. During the remedial investigation, where the ERA,potential remedy, or source attribution depends on the speciation of the PCBspresent in the samples, it may be necessary to consider the more detailed PCBcongener or homolog analysis. It may be appropriate to conduct PCB congener orhomolog analyses on a subset or percentage of the total samples rather than on allsamples.6.4.8 Chlorinated Dioxin, Furans, and Dioxin-like PolychlorinatedBiphenylsThis section is intended to provide guidance on when a dioxin-like(polychlorinated- dioxin, furan, or biphenyl) investigation is warranted and howto perform the investigation, evaluate the data in the EE and ERA, and presentresults.Polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofuran(PCDF), and polychlorinated biphenyls (PCBs) are persistent biomagnifyingcontaminants typically found in the environment as a mixture of congeners, all ofwhich present similar chemical structures. There are 75 possible PCDDcongeners, 135 possible PCDF congeners, and 209 possible PCB congeners. Thecongener pattern in a mixture will vary depending on the source material oroperation that generated these compounds and their toxicity depends on thenumber and location of chlorine atoms.This guidance document focuses on the internationally recognized subset of themost toxic congeners (i.e., the 7 PCDD, 10 PCDF, and 12 PCB compounds) thatcontain laterally-substituted chlorine in the 2, 3, 7, and 8 positions for the PCDDsand PCDFs and laterally-substituted chlorines in the 3,4,5/3’,4’,5’ positions forthe PCBs. To simplify the assessment of the toxicity of these complex mixtures,the USEPA adopted a WHO procedure based on the relative toxicities of the 29Ecological Evaluation Technical Guidance Document 76Version 1.2 8/29/12