By Julie St. Louis
(CN) – Runoff from U.S. farms may be causing more than 12,000 cases of cancer per year as Americans drink up nitrate-polluted tap water, according to a new study published Monday in the scientific journal Environmental Research.
The nonprofit Environmental Working Group conducted the groundbreaking peer-reviewed study to analyze health and economic impacts of agriculture contamination. The scientists estimated the number of cancer cases in each state that could largely be attributed to fertilizer and manure entering public water systems and that of the $1.5 billion cost of treating those cases each year.
“Nitrate contamination of drinking water is a serious problem, and especially severe in the nation’s farm country,” study author and working group senior science advisor Olga Naidenko said. “Now, for the first time, we can see the staggering consequences of this pollution.”
The current federal drinking water standard for nitrate, set in 1962, is 10 parts per million. Yet several well-regarded epidemiological studies have linked nitrate in drinking water with cancer and other serious health issues at levels less than one-tenth of the legal limit. This year, the U.S. Environmental Protection Agency suspended plans to re-evaluate its outdated nitrate standard.
Colorectal cancer accounts for four-fifths of the estimated cases, with ovarian, thyroid, kidney and bladder cancer making up the rest. Serious neonatal health issues have also been linked to nitrate in tap water. Study authors estimated that nitrate pollution may be responsible for close to 3,000 cases of very low birth weight and nearly 2,000 cases of premature births.
“Millions of Americans are being involuntarily exposed to nitrate, and they are also the ones paying the heavy costs of treating contaminated tap water,” toxicologist and primary study author Alexis Temkin said. “But the federal government is not doing enough to protect Americans from tap water contamination.”
In addition to estimating the cases of cancer caused by nitrates in drinking water, scientists also estimate the level at which no adverse health effects would occur. A level of 0.14 milligrams per liter, or 70 times lower than EPA’s current legal limit, would represent a one-in-one-million risk of cancer.