This study has investigated the relationships between socioeconomic status and chemical concentrations in the body, finding that chemical body burdens are affecting people across the poverty spectrum – not just those from economically deprived backgrounds as previously thought.

Taking data from five cross-sectional waves of the U.S. National Health and Nutrition Examination Survey (NHANES), we used linear regression models to investigate the association between 179 toxicants and poverty income ratio. We then selected a subset of chemicals that were associated with poverty in 3 or more NHANES waves, and assessed the potential factors linking chemical build up with income.

Our analysis has shown that Poverty Income Ratio was associated with 18 chemicals in 3 or more NHANES waves.

Individuals with higher socioeconomic status had higher burdens of serum and urinary mercury, arsenic, caesium, thallium, perfluorooctanoic acid, perfluorononanoic acid, mono(carboxyoctyl) phthalate and benzophenone-3.

Whilst lower socioeconomic status was associated with higher levels of serum, urinary lead, cadmium, antimony, bisphenol A and three phthalates: mono-benzyl, mono-isobutyl, mono-n-butyl.

These findings contradict the standard environmental justice hypothesis, which states that lower socioeconomic status will lead to a greater prevalence of harmful elements in the body. Instead, we’ve shown that lifestyle and diet are likely to play a key role in the accumulation of chemicals.

Fish and shellfish consumption was shown to be linked to increases in mercury, arsenic, thallium and perfluorononanoic acid associations, whilst the use of sunscreen was found to be an important factor in the accumulation of benzophenone-3, with people from higher socioeconomic groups more likely to use products containing the chemical.

Cigarette smoking, poor diet and occupation were amongst the factors likely to lead to the build-up of cadmium and lead in those with a higher poverty rating.

Low level chronic exposure to toxicants is associated with a range of adverse health effects and understanding the various factors that influence the chemical burden of an individual is of critical importance to public health strategies. These results provide a comprehensive analysis of exposure patterns as a function of socioeconomic status in US adults, providing important information to guide future public health remediation measures to decrease toxicant and disease burdens within society.

This study is published in the journal Environment International.

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