A Comparative Analysis of the Role Race and Socioeconomic Status Play in Chemical Exposure in the United States

Abstract

Environmental justice concerns arise when historically underrepresented groups are disproportionately exposed to toxins in the environment. Analysis of environmental biomonitoring data provides a method to analyze chemicals for race/ethnicity and income-related disparity. Using data from the US National Health and Nutrition Examination Survey 2013-2014, biomarker concentrations of 167 chemicals were analyzed. Ten subgroups were defined on the basis of race/ethnicity and income. To examine disparity, geometric mean (GM) concentrations of chemical biomarker for each subgroup were compared to a reference group (i.e., the non-Hispanic white individuals with poverty to income ratio ≥ 2). Of the 167 compounds considered, 95 were detected in >60% of samples and were evaluated for disparity. There was evidence of an environmental justice concern for 42 compounds (GM ratios significantly > 1) in at least one of the identified subgroups. For 21 of these compounds, disparity was present only in the low-income non-Hispanic Black subpopulation. Disparity was particularly pronounced for cotinine, propyl paraben, and dichlorophenol. GM ratios were significantly <1 for 16 chemicals, indicating higher exposure among high-income non-Hispanic whites. Cumulatively, this project demonstrates disproportionate exposure to environmental contaminants by income and race/ethnicity. Results suggest that the low-income non-Hispanic Black subpopulation experiences much higher instances of disparity. Comparing with prior research, results also suggest that disparity in environmental exposure may be increasing.