What can we learn from twenty-eight years of monitoring of fish tissue PCBs in Michigan's rivers?

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Department of Civil, Environmental, and Geospatial Engineering


Polychlorinated biphenyls (PCBs) are an important part of chemical legacies in the Laurentian Great Lakes basin. Used in industrial products worldwide, PCBs are now extensively monitored because of their potential toxicity to humans. Fish consumption is a major pathway for exposure. Edible portion (i.e., fish fillet) data from Michigan's fish tissue PCB monitoring program were evaluated using regression statistics, principal component analysis, and t-tests to answer three questions: 1) How do fish tissue total PCB concentrations vary across Michigan's rivers? 2) Are the PCB congener patterns uniformly distributed among tested sites and species? 3) Do monitoring methods limit our ability to discern trends in fish tissue PCB concentrations? Our results indicate that although contaminated sites have been successfully identified, based on higher PCB concentrations in samples from Areas of Concern (AOC) compared to non-AOC sites, 77% of fish samples from 2010-2015 exceeded the safe fish tissue PCB concentration for unrestricted consumption (97 g/day) by sensitive populations. PCB congener profiles vary among species and locations. Results demonstrate that these data are not useful for supplementing ongoing spatial and temporal trend analysis. Only 15 of the 83 species+waterbody pairs had adequate data for evaluating temporal trends with more than three data points. In general, the trends at each location varied based on the analytical method. Conclusions from this work can inform revisions to existing monitoring programs and improve our ability to protect human health.

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This article is protected by copyright. All rights reserved.© 2022 Society of Environmental Toxicology & Chemistry (SETAC). Publisher’s version of record: https://doi.org/10.1002/ieam.4613

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Integrated environmental assessment and management