Concentrations of blood and hair mercury and serum PCBs in an Ojibwa population that consumes Great Lakes region fish

Objective: This paper describes an exposure assessment of an American Indian population using blood and hair samples as indicators of mercury and polychlorinated biphenyl exposure from the consumption of fish taken from the Great Lakes region. Methods: Questionnaires regarding fish consumption were completed by 89 Ojibwa tribal members. Mercury concentrations were determined in human hair and blood samples, and polychlorinated biphenyl concentrations were determined in serum. Results: Fish were consumed at the highest rates in April, May, June, and July. Lake trout, whitefish, and walleye were the preferred fish consumed by 91.4% of the respondents. Concentration of blood mercury were all below 55 mu g/L (ppb), while concentrations of mercury in hair were all less than 3 mg/L (ppm). Hair mercury concentrations were correlated with the previous year's fish consumption (p = .05). Dental amalgams and blood mercury concentrations were also significantly correlated (p < .002). Serum polychlorinated biphenyl concentrations, determined as the sum of 89 congeners, were all below 9.6 ppb total polychlorinated biphenyls. Subject age and total serum polychlorinated biphenyls were correlated (p < .001). Conclusions: The concentrations of mercury and polychlorinated biphenyls in this Ojibwa population were relatively low, but several individuals were identified as having elevated concentrations and additional testing may be warranted. Since the accumulation of contaminants was related to fish consumption and age, a long-term monitoring program that assesses chronic exposure to fish diets would be beneficial.