Tap water across the nation is contaminated with an agricultural pollutant linked to cancer, and the problem is worst in small communities that can least afford to fix it, according to a new EWG analysis.
The contaminant is nitrate, a chemical in commercial fertilizers and manure. EWG’s analysis of tests by public water systems found that 1,700 U.S. communities regularly have levels of nitrate the National Cancer Institute says can increase the risk of cancer. About two thirds of those systems, serving more than three million Americans, have no nitrate treatment process.
The vast majority of systems without nitrate treatment serve 3,300 or fewer people, making the potential treatment cost per person served much more expensive than in larger communities. EWG calculated that in the smallest communities, adding nitrate treatment could cost more than $50 a month per person.
“This is a lose-lose situation for small-town Americans,” said Anne Weir Schechinger, EWG’s senior economic analyst. “If rural communities can’t afford to clean up this problem, which they didn’t cause, residents end up paying with their health. But we can both protect people and spare their pocketbooks by keeping nitrate out of drinking water in the first place.”
Under the federal Safe Drinking Water Act, the legal limit for nitrate in drinking water is 10 parts per million, or ppm, which was set in 1962. But more recent research from the National Cancer Institute has found that drinking water containing 5 ppm or more of nitrate increases the risk of colon, kidney, ovarian and bladder cancers. Other studies have shown links between this level of nitrate pollution and birth defects.
EWG’s Tap Water Database compiles tests by almost 50,000 public water systems nationwide. It shows that in 2014 and 2015, the latest figures available, at least 1,155 communities with average nitrate levels above the increased cancer risk level did not have a treatment system to remove the contaminant from their water.
Nearly 70 percent of these communities were found in ten states: Arizona, California, Illinois, Kansas, Nebraska, New York, Oklahoma, Pennsylvania, Texas and Washington. But nitrate is known to contaminate drinking water in 43 states.
Removing nitrate from tap water is expensive. Larger utilities can spread the cost across many residents, but that’s not an option for smaller utilities, many of them in rural areas with higher than average poverty rates and lower than average household incomes.
Six out of 10 of the water utilities in communities with elevated nitrate levels are classified by the Environmental Protection Agency as very small, serving 500 or fewer people. Nearly 30 percent more are classified as small, serving between 501 and 3,300 people.
EWG found that to fund the treatment needed to reduce nitrate to safe levels, these utilities would need to charge customers additional fees on top of what they already pay for water. Estimated costs per person range from about $30 a year for people served by large utilities to hundreds of dollars for those served by very small utilities. To get nitrate to safe levels in all affected communities could cost as much as $765M a year.
The report didn’t examine the cost of cleaning up nitrate pollution of private wells, which supply drinking water to more than 43 million Americans, including many farm families. In a 2009 study, the U.S. Geological Survey found that 4 percent of the private wells it tested had nitrate levels above the legal limit, but the problem is likely worse in farming areas.
Most nitrate enters drinking water supplies from farm runoff containing fertilizer and animal manure. Agriculture is largely exempt from federal Clean Water Act standards, and the federal government’s attempts to keep farm pollution out of drinking water have relied on farmers’ voluntary efforts through conservation programs subsidized by taxpayers.
“Voluntary efforts aren’t enough,” Weir Schechinger said. “Farmers should do more to help themselves and their neighbors, and they should be required to meet basic standards to prevent pollution. The billions of dollars taxpayers already spend each year to help farmers implement conservation practices should go to farmers willing to exceed these standards.”