Ecological Evaluation Technical Guidance - State of New Jersey

6.1.3.2 BioaccumulationIn calculating levels of exposure, either direct toxicity to plants and wildlife orsecondary toxicity to animals feeding on contaminated plants and animals,one issue that the investigator should be aware of is bioaccumulation.Bioaccumulation is the net extent to which a substance may be accumulatedby an organism because of uptake from various media, including food. A listof contaminants considered to be bioaccumulative can be found in Table 4-2of USEPA (2000c) Bioaccumulation Testing and Interpretation for thePurpose of Sediment Quality Assessment, Status and Needs. A similarconcept is bioavailability, which is the net extent to which the form of achemical occurring in a medium is susceptible to being taken up by anorganism. Bioavailability is (1) the cumulative expression of physical,chemical, and biological processes evident in air, water, soil, and sediment,and (2) biological factors present in the bodies, organs, tissues, or cells ofexposed organisms that act to change that organism's rate of COPEC exposure(Suter et al., 2000).To be consistent with the first two steps of ERAGS, the EE must assume that100 percent of a particular COPEC that is identified in a particular media isavailable to the representative receptors being evaluated (N.J.S.A. 58:10B-12). While this is generally considered to be an overestimation of ecologicalrisk, it provides a level of certainty if the conclusion of the EE is that noecological risks are evident. However, in the ERA, the investigator shouldconsider bioaccumulation when calculating the levels of exposure to beevaluated in the risk assessments, particularly in calculations of impacts tohigher trophic level organisms through food chain transfer of a COPEC.When sediment and soil chemistry data are available, but tissue chemistry isnot, Sediment/Soil-to-Biota Bioaccumulation Factors (BSAFs) andBioaccumulation Factors (BAFs), respectively, can be estimated for selectcompounds using published accumulation factors(http://el.erdc.usace.army.mil/bsafnew/,andhttp://www.epa.gov/med/Prods_Pubs/bsaf.htm). Such data should be usedwith caution because it is not site specific and could overestimate orunderestimate accumulation.The BSAFs and BAFs are the ratios of tissue concentrations to the sedimentandsoil-associated concentrations of organic compounds or metals. A sitespecificBSAF or BAF can be empirically determined through collection andchemical analysis of collocated sediment or soil, respectively, and organismtissue. Because some contaminants bind to organic matter in sediment andsoil or to lipids in the tissue of exposed organisms, site-wide BSAF and BAFvalues need to be normalized for TOC and for lipid content (USEPA, 2009c).In ERAs for complex situations, studies to more accurately predictbioaccumulation and the movement of a COPEC through the environmentshould be considered. Generally, these studies will consist of field-collectedtissue samples (both plant and animal) at different trophic levels of theEcological Evaluation Technical Guidance Document 41Version 1.2 8/29/12