South Dakota Activities
Investigation of Blood Mercury Concentrations in Fish-Consuming People Residing on the Cheyenne River Sioux Reservation
The National Center for Environmental Health (NCEH) Health Studies Branch (HSB) collaborated with the EPA to determine blood mercury concentrations among people living in areas that currently have: (1) a high environmental burden of mercury; (2) plans in place to reduce environmental emissions and deposition of mercury over time; (3) mercury concentrations in fish tissue are high; (4) consumption of locally caught fish is common. The purpose of study was to determine the feasibility of identifying persons with high Methylmercury (MeHg) concentrations that are living in areas identified by EPA to have high mercury emissions and deposition. The study was implemented at three sites, one of which included the Cheyenne River Sioux Tribe (CRST) from South Dakota. The CRST residents regularly consume locally caught fish despite consumption advisories due to elevated mercury in surface waters and fish. This study aimed to quantify mercury exposure among tribal residents who consumed at least two weekly servings of locally caught fish. Participants completed a questionnaire designed to collect demographic data, the average number of servings of all fish and locally caught fish consumed per week during the preceding month, locations where fish were caught, and types of fish consumed. Blood specimens were collected to quantify mercury levels. All laboratory analyses and epidemiologic analyses have been completed at each site, and results have been provided to study partners and presented at national conferences. Analyses combining data from all three sites has begun, with manuscript writing to follow.