Researchers at the Columbia University Mailman School of Public Health recently conducted a study on metal concentration in U.S. community water systems (CWS) and patterns of inequality. The study revealed that metal concentrations were particularly concentrated in CWSs serving semi-urban, Hispanic communities independent of location or region, highlighting environmental justice concerns. These types of communities had the highest levels of uranium, selenium, barium, chromium, and arsenic concentration.
Even if the concentration is low, uranium represents an important risk factor for the development of chronic diseases. Unfortunately, until now little epidemiological research has been done on chronic water uranium exposure despite the potential health effects of uranium exposure from CWSs. Uranium has been underappreciated in the literature as a major public drinking water contaminant. The results of the study have been published in the journal The Lancet Planetary Health.
Anne Nigra, Ph.D. is an assistant professor of Environmental Health Sciences at Columbia Mailman School of Public Health. She said, “Previous studies have found associations between chronic uranium exposure and increased risk of hypertension, cardiovascular disease, kidney damage, and lung cancer at high levels of exposure. Our objectives were to estimate CWS metal concentrations across the U.S, and identify sociodemographic subgroups served by these systems that either reported high metal concentration estimates or were more likely to report averages exceeding the US EPA's maximum contaminant level (MCL).”
About ninety percent of U.S. residents depend on public drinking water systems. Most resident rely on CWS that that serve the same population year-round. The researchers evaluated EPA six-year review records for antimony, arsenic, barium, beryllium, cadmium, chromium, mercury, selenium, thallium, and uranium. They were trying to determine if average concentrations exceeded the maximum contaminant levels allowed by the EPA which regulates levels for six different classes of contaminants. The review included about thirteen million from one hundred and thirty-nine thousand CWS serving two hundred and ninety people annually. They created an online interactive map of estimated metal concentrations at the CWS and county levels to use in future analyses.
According to the report, two percent of community water systems reported average uranium concentrations from 2000 to 2011 which exceeded the EPA maximum contamination levels. Uranium was often detected during compliance monitoring. Arsenic, barium, chromium, selenium, and uranium concentrations were also disproportionately elevated in CWSs which served semi-urban, Hispanic populations. This raised concerns for these communities and the possibility of inequalities in public drinking water.
Nigra and her team found that the consistent association between elevated CWS concentrations and semi-urban, Hispanic communities suggested that concentration disparities are either a failure of regulatory policy or water treatment rather than underlying geology. Hispanic/Latin populations show numerous health disparities. These included increased mortality due to diabetes as well as liver, kidney and cardiovascular disease.
Niger said, “Additional regulatory policies, compliance enforcement, and improved infrastructure are therefore necessary to reduce disparities in CWS metal concentrations and protect communities served by public water systems with elevated metal concentrations. Such interventions and policies should specifically protect the most highly exposed communities to advance environmental justice and protect public health.”