New report shows where cancer-causing chemicals are polluting water for over 200 million Americans
More than 200 million people are at risk of drinking tap water contaminated with chemicals that cause cancer, liver damage, birth defects and other reproductive harms, according to research released Wednesday that includes an interactive map of high-risk hot spots.
The map, developed by the Environmental Working Group (EWG), focuses on arsenic, chromium-6 and nitrate – all scientifically known to cause cancer and other health problems.
Nitrates, commonly generated by the use of fertilizers on farmland, not only have been shown to cause cancer but also to negatively impact blood oxygen levels in babies. Infants who consume nitrates in drinking water can suffer from what is known as “blue baby syndrome.” As well, research shows that pregnant women exposed to nitrates in drinking water face risks of problematic birth outcomes, including low birth weights and pre-term birth.
Of the three chemicals examined in the report, nitrate affects the most people in terms of tap water. EWG said nitrate is affecting the tap water of an estimated 263 million Americans in 49 states served by 26,644 water systems. Nitrate-contaminated drinking water has been a dire problem for many farm states, particularly the top corn-growing state of Iowa in recent years, and researchers fear it is driving skyrocketing cancer rates.
Iowa has the second-highest rate of cancer in the nation, and has become one of only two US states where cancer overall is increasing. Leukemia, as well as cancers of the pancreas, breast, stomach, kidney, thyroid and uterus, are among the different cancer types on the rise across Iowa, according to the National Cancer Institute. Nitrates have routinely been found at levels above the 10 milligrams per liter federal regulators set as a safe standard. And nitrate levels this summer in Iowa were so far above federal standards that the utility serving 600,000 people in and around the state capital of Des Moines restricted water use because the utility could not safely clear the high levels.
Many scientists see the current EPA benchmark of 10 milligrams per liter as far too high to be truly protective. EWG said that standard does not fully protect against cancer risk or harm to a developing fetus. EWG’s health guideline is 0.14 ppm, which it says would reduce the cancer risk level to one in one million.
Also of concern is the widespread contamination of tap water with chromium-6, also known as hexavalent chromium. EWG researchers said it contaminates the tap water of an estimated 260 million people served by 7,538 utilities, primarily in Arizona and California. Even low levels of this contaminant increases the risk of reproductive problems, liver damage and stomach cancer.
Chromium-6 is the toxic form of the metal chromium and primarily is generated by industrial processes. Some forms of chromium occur naturally in the environment in soil and rocks but are less toxic.
The 2000 movie “Erin Brockovich” brought chromium-6 to public attention, focusing on the story of a Californian utility company that poisoned groundwater in the area with chromium-6, sickening families. California has been moving in recent years both to regulate the heavy metal and to reduce its use, and has set a maximum contaminant level of 10 micrograms per liter. EWG says the maximum allowed should be 0.02 parts per billion (ppb).
The mapping research also includes data indicating arsenic contaminates water serving an estimated 134 million people in 50 states through 12,945 utilities. Arsenic also occurs naturally in the environment but is highly toxic in its inorganic form. It is linked to cardiovascular disease and diabetes, harm to childhood cognitive development and increased deaths in young adults.
The EPA’s drinking water limit for arsenic is 10 ppb, though EWG says a better guideline is 0.004 ppb.
The data used to produce the map was reported by utilities to state regulators and gathered by EWG. It is based on data submitted through 2023 and reflects a three-year average, said EWG senior science analyst Sydney Evans.
Evans said the data is yet more evidence that utilities need to install water filtration systems such as ion exchange that can effectively reduce these and other harmful water contaminants. A recently published study shows using specialized filtration to reduce chromium-6 and arsenic concentrations in drinking water could prevent an estimated 50,000 cancer cases.
