A Method to screen U.S. environmental biomonitoring data for race/ethnicity and income-related disparity

BACKGROUND: Environmental biomonitoring data provide one way to examine race/ethnicity and income-related exposure disparity and identify potential environmental justice concerns. METHODS: We screened U.S. National Health and Nutrition Examination Survey (NHANES) 2001–2008 biomonitoring data for 228 chemicals for race/ethnicity and income-related disparity. We defined six subgroups by race/ethnicity—Mexican American, non-Hispanic black, non-Hispanic white—and income—Low Income: poverty income ratio (PIR) <2, High Income: PIR ≥ 2. We assessed disparity by comparing the central tendency (geometric mean [GM]) of the biomonitoring concentrations of each subgroup to that of the reference subgroup (non-Hispanic white/High Income), adjusting for multiple comparisons using the Holm-Bonferroni procedure. RESULTS: There were sufficient data to estimate at least one geometric mean ratio (GMR) for 108 chemicals; 37 had at least one GMR statistically different from one. There was evidence of potential environmental justice concern (GMR significantly >1) for 12 chemicals: cotinine; antimony; lead; thallium; 2,4- and 2,5-dichlorophenol; p,p’-dichlorodiphenyldichloroethylene; methyl and propyl paraben; and mono-ethyl, mono-isobutyl, and mono-n-butyl phthalate. There was also evidence of GMR significantly <1 for 25 chemicals (of which 17 were polychlorinated biphenyls). CONCLUSIONS: Although many of our results were consistent with the U.S. literature, findings relevant to environmental justice were novel for dichlorophenols and some metals.