Researchers from the Environmental Working Group (EWG) in Washington, DC, used a new approach to analyze cumulative cancer risk due to cancer-causing chemicals in tap water across the U.S.
They note that the study is the first to apply a “cumulative cancer risk framework” to the analysis of tap water contaminants for the whole of the U.S.
The analysis drew on water quality data from 48,363 community water systems across the country.
The dataset did not include private wells, which supply drinking water to around 14% of the U.S. population, or about 13.5 million households.
The analysis revealed that the most significant impact on cancer risk came from arsenic, followed by byproducts of disinfection.
“Drinking water contains complex mixtures of contaminants, yet government agencies currently assess the health hazards of tap water pollutants one by one,” says first and corresponding study author Sydney Evans, an EWG science analyst.
“In the real world,” she adds, “people are exposed to combinations of chemicals, so it is important that we start to assess health impacts by looking at the combined effects of multiple pollutants.”