Estimated exposure to mercury from fish consumption among women anglers of childbearing age in the Great Lakes region

Abstract

Women of childbearing age (WCBA) are advised by state, tribal, and federal agencies to limit their consumption of certain fish, in part, because of concerns about the ingestion of methylmercury and its impact on the development of fetuses. We studied the fish-eating habits of WCBA who had a fishing license and lived near the Great Lakes, where mercury in locally-caught fish is a concern, as these women were likely at greater risk of elevated mercury exposure than the general population. We used a web-based diary method to gather fish consumption data from WCBA anglers over a 4-month period in the summer of 2014. We estimated mercury intake based on reported mercury content of species consumed, frequency of consumption, and meal portion size, and calculated percent exceeding the USEPA reference dose (RfD). Based on these calculations, we estimated that study participants (n = 1395) ingested 0.031 ± 0.002 (95% CI) ug/kg/d of methylmercury (arithmetic mean). We also found that 3.4% of study participants exceeded the RfD when we averaged estimated intake over the 4-month study period. While most (82%) of the fish meals WCBA anglers ate were purchased fish meals generally low in mercury, study participants ingested a disproportionate amount of mercury from locally-caught fish meals (18% of meals contributed 37% of mercury intake). We estimated 11% of WCBA anglers who did not follow state and federal guidelines in effect at the time of our study exceeded the mercury RfD, whereas fewer than 1% of WCBA anglers who followed the guidelines exceeded the RfD. These findings highlight the importance of encouraging WCBA to follow guidelines from agencies for locally-caught fish, in combination with guidelines for purchased fish.

Keywords: Dietary mercury exposure; Fish consumption guidelines; Great Lakes; Methylmercury; Women of childbearing age.