Mercury exposure in an urban pediatric population

Objective. - To determine the prevalence of elevated urinary mercury (Hg), as a marker of exposure, in a population of children drawn Methods. - A prospective consecutive patient series was conducted from November 1998 to January 1999 at an inner-city clinic in New York. Anonymous urine specimens from subjects (aged 1-18 years) were collected in mercury-free containers, split, acidified with 1:100 hydrochloric acid, and frozen. Cold-vapor atomic absorption spectrofluorometric assays were conducted simultaneously at laboratories at the University of Washington and the New York City Department of Health. Results. - We enrolled 100 children (mean age 9.4 years; 62% male; 55% Hispanic; and 43% African American). Assay results from both laboratories were strongly correlated (r = 0.8, P < .0001). Mean urinary Hg was 1.08 ± 1.82 μg/L. The 95th percentile for urinary Hg was 2.8 μg/L (range 0.2 to 11.7 μg/L). Five subjects had Hg levels above 5 μg/L. Conclusion. - We found that 5% of subjects had unsuspected elevated urinary Hg levels. This finding, in a group of inner-city minority children, strongly supports the need for further investigation of the sources of mercury exposure in this population.