Ecological Evaluation Technical Guidance - State of New Jersey

While there are many laboratories that can produce acceptable analyticalresults for soil and sediment samples, not all laboratories are capable of tissueanalysis. Tissue processing requires specialized equipment in addition to thestandard analytical instrumentation, and some laboratories cannot work withsmall samples. Tissue samples, particularly samples with high lipid content,may also present analytical interference that can yield excessively highanalytical detection limits for insufficiently experienced laboratories.It is critical to discuss bioaccumulation study objectives with both the toxicitytesting laboratory and the analytical laboratory, to ensure that data qualityobjectives are met.6.1.3.3 Toxicity Reference ValuesToxicity reference values (TRV) are literature-based levels defined as a doseabove which ecologically relevant effects might occur in wildlife speciesfollowing chronic dietary exposure and below which it is reasonably expectedthat such effects will not occur (USEPA, 2005a). TRVs provide a basis forestimating whether the exposure to COPECs at a site is likely to result inadverse ecological effects (e.g., survival, growth, and reproduction of wildlifespecies). The TRVs selected in the ERA are based on LOAELs and/orNOAELs from laboratory and/or field-based studies reported in the scientificliterature (USEPA, 2005a and Sample et al., 1996).Risks are estimated for appropriate feeding guilds by comparing the results ofthe measured or modeled dietary contaminant doses to receptors of concern tothe TRVs. The ratio of these two numbers is called a Hazard Quotient (HQ).HQs equal to or greater than one (HQ ≥ 1) are typically considered to indicatepotential risk to ecological receptors. If an HQ suggests that effects are notexpected to occur for the average individual, then the effects are likely to beinsignificant at the population level; however, if an HQ indicates risks arepresent for the average individual, then risks may be present for the localpopulation.The basic equation used for calculation of an HQ value for exposure of awildlife receptor to a chemical by ingestion of an environmental medium is:HQi, j, r = ADDoTRVi,rwhere:HQi,j,r = HQ for exposure of receptor “r” to COPEC “i” in medium “j”ADD = Average Daily Dose (mg/kgBW-day)oTRVi,r = Oral TRV for COPEC “i” in receptor “r” (mg/kg-day)Because all receptors are exposed to more than one environmental medium,the total hazard to a receptor from a specific COPEC is calculated as the sumof HQs for that COPEC across all media:HQi, r = Σ HQi, j, rEcological Evaluation Technical Guidance Document 46Version 1.2 8/29/12