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A National Probabilistic Study of Polybrominated Diphenyl Ethers in Fish from US Lakes and Reservoirs
Citation:
Stahl, L., B. Snyder, Tony Olsen, AND L. Walters. A National Probabilistic Study of Polybrominated Diphenyl Ethers in Fish from US Lakes and Reservoirs. ENVIRONMENTAL MONITORING AND ASSESSMENT. Springer, New York, NY, 185(12):10351-10364, (2013).
Impact/Purpose:
As part of U.S. EPA’s National Study of Chemical Residues in Lake Fish Tissue, this study generated the first national freshwater fish contamination dataset to allow a statistically valid evaluation of PBDEs in lakes and reservoirs of the conterminous U.S. The probabilistic design allowed the development of cumulative distribution functions (Figure 3) to quantify PBDE concentrations versus the cumulative number or percentage of U.S. lakes from the sampled population of 76,559 lakes for predator species and 46,190 lakes for bottom dwellers. These probability distributions provide the means for applying emerging human health risk-based screening values to estimate the percentage of the nation’s lakes with PBDE fish tissue concentrations that exceeded a particular health protection endpoint at the time of this study. The results of this probabilistic survey also provide national baseline information to track changes in PBDE concentrations in U.S. freshwater fish over time. Further efforts are warranted to examine temporal trends in PBDE levels in U.S. freshwater fish (particularly considering the known and proposed changes in PBDE production and uses) and to develop national risk-based consumption limits or human health screening values for PBDEs in fish.
Description:
National estimates were developed for polybrominated diphenyl ethers (PBDEs) in fish from lakes and reservoirs of the conterminous United States (excluding the Laurentian Great Lakes and Great Salt Lake) using an unequal probability design. Predator (fillet) and bottom-dweller (whole-body) composites were collected from 166 lakes selected randomly from the target population of 147,343 lakes in the lower 48 states. Both composite types comprised nationally representative samples that were extrapolated to the sampled population of an estimated 76,559 lakes for predators and 46,190 lakes for bottom dwellers. Fish tissue samples were analyzed for 34 individual PBDE congeners and six co-eluting congener groups of two congeners each. All fish samples contained detectable levels of PBDEs; however, four congeners were not detected in any samples. Frequency of occurrence was dominated by 9 congeners or congener pairs based on detections in greater than 75% of all samples. The predominant congeners for both predators and bottom dwellers were BDE-47, BDE-49, BDE-99, and BDE-100. The highest single congener concentrations were reported for BDE-47. The maximum aggregated sums of analyzed PBDE congeners ranged from 38.3 ng/g in predator fillets to 125 ng/g in bottom dweller whole bodies. Maximum PBDE concentrations in fish from this national probabilistic study were higher than those reported from other targeted studies of inland lakes in the U.S. but lower than those published for Great Lakes studies. The probabilistic design allowed the development of cumulative distribution functions to quantify PBDE concentrations versus the cumulative number or percentage of U.S. lakes from the sampled population. These probability distributions provide the means for applying emerging human health risk-based screening values to estimate the percentage of the nation’s lakes with PBDE fish tissue concentrations that exceeded a particular health protection endpoint.