Use of Biota-Sediment Accumulation Factors to Assess Similarity of Nonionic Organic Chemical Exposure to Benthically-Coupled Organisms of Differing Trophic Mode

Abstract

The U.S. Environmental Protection Agency is in the process of developing Sediment Quality Criteria (SQC) to specify the acceptable degree of risk from sediment-mediated chemical exposure for the protection of benthically-coupled organisms. In this study, potential differences in chemical exposure for benthic organisms of differing habitats or feeding types were evaluated through the use of Biota-Sediment Accumulation Factors (BSAFs). It was hypothesized that If species of different habitats have similar exposures, then the BSAF values should not be different. The BSAFs are calculated using the concentrations of chemicals in an organism (&mgr;g/g lipid) divided by the concentrations of the same chemicals in sediment (&mgr;g/gOC). Data from both freshwater and saltwater studies that met specified criteria for data quality were obtained from published papers or reports. These included three laboratory and five field studies containing 27 species and 4054 BSAF values. The BSAFs were intercompared for similarity of central tendency as grouped by chemical class (PCBs, PAHs, pesticides), individual species, and species grouped by habitat (infaunal deposit feeder, scavenger, filter feeder, and benthically-coupled fish). Plots of BSAFs grouped by class and KOW revealed that the BSAFs for the PAHs were uniformly lower (mean 0.34) than the PCB (1.03) or pesticide (1.36) classes. For the PCBs, the BSAFs for all species exhibited a KOW dependency with decreased bioaccumulation evident above and below the range of 5.99-7.27 log10 KOW. In order to optimize the detection of species/habitat differences in the BSAFs, further analyses were segregated by chemical class and excluded PCB data outside the above KOW range. These analyses revealed similar BSAF values for various species both within and among habitat groups, and indicated that the sum total of exposures from all routes is similar across species. This similarity of chemical exposure across benthic species, and the similarity of sensitivities between benthic species and species used to derive WQC FCVs supports the applicability of SQC for all benthic organisms as a group.

Optimization of Marine Triterpene Sipholenols as Inhibitors of Breast Cancer Migration and Invasion

“…Polybrominated diphenyl ethers with the largest BSAFs 28 (BDEs 28/33, 66) had log K OW of approximately 6 to 7, with lower accumulation of the more hydrophobic congeners. This trend was generally consistent with other studies investigating BDE uptake by deposit feeders 27, 28, other studies of HOC uptake by deposit feeders 36, and highly chlorinated PCBs specifically 37. For HOCs with log K OW greater than 7, bioavailability generally decreases with increasing molecular weight because of stronger associations with sediment particles and lower solubility in water and digestive fluids.…”

Effects of sedimentary sootlike materials on bioaccumulation and sorption of polychlorinated biphenyls

“…Di-ortho PCBs are numbers 18, 52, 101, and 138; mono-ortho PCBs are numbers 28, 72, 118, and 156; and nonortho PCBs are numbers 77, 126, and 169. The BSAF values increase with increasing degree of chlorination, but for the very hydrophobic hexachlorobiphenyls with octanol-water partition coefficients (K OW s) of approximately Ն10 7.0 , values tend to level off or even decrease [16,[26][27][28]33]. Within a subgraph, BSAFs of PCBs with the same number of chlorine atoms (PCBs with similar hydrophobicity) are pooled together, and the two (trichlorobiphenyls) or three (tetra-hexachlorobiphenyls) bars within each cluster are presented in increasing order of planarity (from left to right).…”

“…Within a subgraph, BSAFs of PCBs with the same number of chlorine atoms (PCBs with similar hydrophobicity) are pooled together, and the two (trichlorobiphenyls) or three (tetra-hexachlorobiphenyls) bars within each cluster are presented in increasing order of planarity (from left to right). Therefore, this leveling off or decrease probably is due to the larger molecular volume of these congeners because of which it is difficult for molecules to penetrate lipid bilayers of cell membranes [16,26,33]. 2a) is a function of both planarity and hydrophobicity.…”

Processes, Assessment and Remediation of Contaminated Sediments

“…The limitations and sources of uncertainty associated with the use of the TBP model are discussed in Moore et al (2005) and references therein. The quality of TBP estimations is highly dependent on selecting adequate BSAF values, for which variability may reach several orders of magnitude for a given species and compound or class of compound (Tracey and Hansen, 1996;Moore et al, 2005). BSAF values are typically derived from single sediment-tissue data pairs derived from laboratory for field bioaccumulation testing or from co-located sediment and tissue collected from a field-site.…”