Environmental justice and drinking water quality: are there socioeconomic disparities in nitrate levels in U.S. drinking water?

Epidemiological evidence for health effects associated with drinking water above 5 mg/L NO₃-N raises concerns about increased risk for the 5.6 million Americans served by public water supplies with average nitrate concentrations above this level. The associations we observed between nitrate concentrations and proportions of Hispanic residents support the need for improved efforts to assist vulnerable communities in addressing contamination and protecting source waters. Future studies can extend our methods to evaluate disparities in exposures to other contaminants and links to health effects.