Biomonitoring of Mercury and Persistent Organic Pollutants in Michigan Urban Anglers and Association with Fish Consumption

Abstract

The 32-mile Detroit River and surrounding tributaries have been designated as a Great Lakes Area of Concern due to pollution from decades of municipal and industrial discharges, sewer overflows and urban development. Key pollutants in fish samples from the Detroit River include mercury, polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), dioxins and furans. A biomonitoring study was conducted to assess exposures to these persistent toxic substances in Detroit urban anglers who may be at higher exposure risk due to consumption of locally caught fish. Using a modified venue-based sampling approach, 287 adult shoreline anglers along the Detroit River were recruited and participated in the program. Study participants provided blood and urine specimens and completed a questionnaire interview. We examined percentile estimates for total blood mercury, PCBs, DDE, and dioxin-like total toxic equivalency (TEQ) concentrations among study participants compared with the general U.S. population. Multiple linear regression was used to identify important predictors of contaminant concentrations. Quantile regression was used to investigate whether eating locally caught fish had a differential effect at various quantiles of each contaminant. Participants reported eating an average of 20 Detroit River caught fish meals in the past year. The Detroit urban anglers’ total blood mercury and PCB concentrations were 2 to 3 times higher than the general U.S. population. Elevated levels of DDE and total TEQ concentrations were not observed in the cohort. Eating more locally caught fish was associated with higher total blood mercury and serum PCB concentrations, and this effect had a larger impact at higher quantiles of these biomarkers. The biomonitoring data served to inform public health officials and guide state and local public health actions to reduce harmful exposures.