A biomonitoring study of lead, cadmium, and mercury in the blood of New York City adults

Objectives: We assessed the extent of exposure to lead, cadmium, and mercury in the New York City (NYC) adult population. Methods: We measured blood metal concentrations in a representative sample of 1,811 NYC residents as part of the NYC Health and Nutrition Examination Survey, 2004. Results: The geometric mean blood mercury concentration was 2.73 μg/L [95% confidence interval (CI), 2.58-2.89]; blood lead concentration was 1.79 μg/dL (95% CI, 1.73-1.86); and blood cadmium concentration was 0.77 μg/L (95% CI, 0.75-0.80). Mercury levels were more than three times that of national levels. An estimated 24.8% (95% CI, 22.2-27.7%) of the NYC adult population had blood mercury concentration at or above the 5 μg/L New York State reportable level. Across racial/ethnic groups, the NYC Asian population, and the foreign-born Chinese in particular, had the highest concentrations of all three metals. Mercury levels were elevated 39% in the highest relative to the lowest income group (95% CI, 21-58%). Blood mercury concentrations in adults who reported consuming fish or shellfish 20 times or more in the last 30 days were 3.7 times the levels in those who reported no consumption (95% CI, 3.0-4.6); frequency of consumption explained some of the elevation in Asians and other subgroups. Conclusions: Higher than national blood mercury exposure in NYC adults indicates a need to educate New Yorkers about how to choose fish and seafood to maximize health benefits while minimizing potential risks from exposure to mercury. Local biomonitoring can provide valuable information about environmental exposures.