Total blood mercury concentrations in the US population: 1999-2006

We describe the distribution and demographic characteristics of total blood Hg levels in the U.S. general population among persons ages I year and older who participated in the 2003-2006 National Health and Nutrition Examination Survey (NHANES). We also describe trends in the total blood Hg of children ages 1-5 (n = 3456) and females ages 16-49 during 1999-2006 (n = 7245). In the combined 2003-2006 survey periods, the geometric means for non-Hispanic blacks, 0.853 mu g/L (95% confidence interval [CI], 0.766-0.950 mu g/L), and non-Hispanic whites, 0.833 mu g/L (95% Cl, 0.752-0.922 mu g/L), were higher than the geometric mean for Mexican Americans, 0.580 mu g/L (95% Cl, 0.522-0.645 mu g/L). Also in 2003-2006, regression analysis of log total blood Hg with age, race/ethnicity and gender showed that total blood Hg levels in the population exhibited a quadratic increase with age (p<0.0001), peaking at ages 50-59 in non-Hispanic blacks and whites, at ages 40-49 in Mexican Americans, and then declining at older ages. Over the four survey periods (1999-2006), regression analysis showed that total blood Hg levels increased slightly for non-Hispanic white children and decreased slightly for non-Hispanic black and Mexican American children. Over the same four survey periods, female children had slightly higher total blood Hg levels than males (0.356 vs. 0.313 mu g/L, p = 0.0050) and total blood Hg levels in non-Hispanic black women aged 16-49 years were significantly higher than in non-Hispanic white women (1.081 vs. 0.850 mu g/L, p<0.0001) and in Mexican American women (1.081 vs. 0.70 mu g/L, p < 0.0001). Published by Elsevier GmbH.