Ecological Evaluation Technical Guidance - State of New Jersey

Appendix I - Using the Toxic Equivalency (TEQ) Approach to Evaluate Dioxin,Furan, and Dioxin-like PCB ResultsAnalytical MethodsLaboratories performing dioxin analysis must be certified by NJDEP for either USEPASW846 Method 8290 or USEPA Method 1613B (N.J.A.C. 7:26E-2.1(a)1) (USEPA1994b and 1994c). Laboratories performing PCB congener analysis must be certified byNJDEP for USEPA Method 1668A/B (USEPA 1999c). Full laboratory deliverables arerequired per N.J.A.C. 7:26E 2.1(a)15i.If a phased approach to sampling is used, samples from outside the source area may bestored at the laboratory until source area results are reviewed. Samples for dioxinanalysis in soil, sediment, wipe, and chip samples may be archived at the laboratory forup to one year to extraction, followed by one year to analysis. Stored nonaqueoussamples are to be kept in the dark at or below -10 o C. Stored aqueous samples are to bekept in the dark at zero to four degrees C. Sample extracts from both may be stored inthe dark, below -10 o C for one year.TEQ ApproachAs described in 6.4.7, 17 dioxin and furan congeners and 12 dioxin-like PCBs producesimilar biological effects with varying potencies and generally act together in an additivefashion. To facilitate the assessment of the most toxic components of these complexmixtures, the 29 dioxin-like congener concentrations from biotic and abiotic media aremultiplied by internationally recognized toxic equivalency factors (TEFs), which areorder of magnitude estimates of the toxicity of the individual congeners relative to2,3,7,8-TCDD that have been developed by the World Health Organization (WHO);2,3,7,8 - TCDD is assigned a TEF of 1. The resulting concentrations are summed todetermine the TEQ concentration. Each of the 29 designated dioxin-like compounds hasbeen assigned a fish, avian, and mammalian TEF (Van den Berg et al., 1998, 2006;www.who.int/ipcs/assessment/tef_update/en/print.html). Only the 2,3,7,8-substitutedPCDDs and PCDFs are factored into the summation for the sample TEQ (i.e., those listedby the laboratory as “other dioxins,” per congener category, are not included in the TEQ).Evaluation of Dioxins, Furans, and Dioxin-like PCBs for initial screening in theEcological EvaluationIn the ecological evaluation (EE), the TEQ approach is used to initially characterize,screen, and present dioxin, furan, and dioxin-like PCB data by using TEFs for onereceptor class for a consistent and streamlined evaluation. The application of the avianTEFs to dioxin, furan, and dioxin-like PCB concentrations in abiotic media (soil,sediment, surface water) is recommended. The reasons for selecting the avian TEFs areas follows: Among the avian, mammalian, and fish TEFs, the avian and mammalianTEFs are generally similar and more conservative than the fish TEFs. Between the avianand mammalian TEFs, while the TEFs for PCB 126 (a highly toxic WHO PCB congener)are identical, the avian TEF for PCB 77 is higher than the mammalian, resulting in amore conservative TEC for PCB 77. It is appropriate to focus on PCB 77 in thescreening process since it is detected in media samples at greater frequency and at higherconcentrations than PCB 126. Therefore, using avian TEF scheme is the mostEcological Evaluation Technical Guidance Document 125Version 1.2 8/29/12