Blood and urine levels of long half-life toxicants by nativity among immigrants to the United States

One's place of birth is a major determinant of his or her exposure to environmental toxicants. By understanding biological burdens of long half-life toxicants by race and nativity we can better understand geographic variation in toxicant distribution. We used the National Health and Nutrition Examination Survey (1999-2006) biomonitoring data to examine differences in blood and urine levels of long half-life environmental toxicants of foreign-born relative to US-born people by race/ethnicity. We log transformed blood and urine measures of 51 environmental toxicants. We then used "seemingly unrelated regression," a robust technique for making multiple comparisons across a group of variables with correlated error terms, to examine differences in blood and urine toxicants by nativity and race. We found that, compared to native-born Americans, the foreign-born are generally more likely to be exposed to metals (p < 0.001) and organochlorine pesticides (p < 0.001), but less likely to be exposed to dioxin-like compounds (p < 0.001) or polyflourinated compounds (p < 0.001). While levels of toxicants varied greatly by region of birth, US-born participants had consistently higher levels of dioxin-like compounds and polyflourinated compounds.