Nearly 100million Americans are being exposed to water contaminated with potentially cancer-causing substances. 

A new study found one-third of the country is drinking water full of unregulated – and unknown – contaminants that could have major impacts on their health. 

Researchers from the Silent Spring Institute, a nonprofit studying the effects of the environment on cancer, looked at data from more than 4,800 water sources and found 27 percent – supplying 97million people – had detectable levels of at least one of four chemicals.

Several of which have been linked to organ damage, cancer, and hormone imbalances.

Co-author Laurel Schaider, a scientist at the Silent Spring Institute, said: ‘We know there are thousands of other harmful chemicals that are not regulated that make their way into groundwater and surface waters, and some of these chemicals can ultimately end up in drinking water supplies.’ 

Researchers also found communities with a higher proportion of Hispanic and Black residents generally had higher levels of the contaminants and were more likely to be closer to major polluters, such as wastewater treatment plants, airports, military training sites, and industrial areas.

Lead author Aaron Maruzzo, also a scientist at Silent Spring Institute, added: ‘Our findings show that the percentage of Hispanic and Black residents in a community is a consistent predictor of poorer water quality.’

The federal government only regulates a fraction of the total number of contaminants lurking in millions of Americans’ water. This leaves it up to states to set safety limits, but only in certain areas, meaning many people are unknowingly exposed.

The map compiled by the US Geological Survey shows the number of PFAS detections across a sprawling number of sites nationwide between 2016 and 2021

The team analyzed data from the 4,815 water sources part of the Environmental Protection Agency’s (EPA) Unregulated Contaminant Monitoring program collected between 2013 and 2015.

This program collects data for contaminants suspected to be present in drinking water that do not have established standards set under the Safe Drinking Water Act.

The program monitors all public water systems, including small (serving 3,300 to 10,000 people) and large (serving more than 10,000 people), as well as a set of water systems that serve fewer than 3,300 people.

It was developed to investigate a list of contaminants that are not currently regulated, are suspected of or anticipated to be present in public water systems, and those that experts believe should be regulated under the Safe Drinking Water Act, which currently tests for and regulates nearly 100 contaminants.

The four chemicals Silent Spring analyzed included 1,4-dioxane, a solvent classified by the EPA as a probable human carcinogen. It is found in consumer products like cosmetics, laundry detergents, and shampoos.

Long-term exposure can increase the risk of liver and kidney damage and liver tumors.

Second was the group of ‘forever chemicals’ known as PFAS (per- and polyfluoroalkyl substances). These nonstick chemicals are widely used in consumer products, from rain jackets to cookware. 

They have been associated with cancer, thyroid disease, high cholesterol and a myriad of other health problems.

The third substance was chlorodifluoromethane (Freon 22), an ozone-depleting gas previously used as a refrigerant and used in the production of fluoropolymers, such as Teflon.

Researchers from the Silent Spring Institute found detectable levels of at least one of four chemicals in 27 percent of over 4,800 water sources, affecting 97 million people

The contaminant is particularly harmful when inhaled, causing confusion, drowsiness, heart palpitations, and organ injury.

Lastly, they analyzed levels of 1,1-dichloroethane, a solvent used in paints, plastics, and pesticides that has been associated with cancer.

Of the sites they tested, 22 percent had detectable levels of 1,4-dioxane, six percent had levels of chlorodifluoromethane, 4.7 percent had levels of 1,1-dichloroethane, and four percent contained PFAS.

Unregulated contaminated water systems were more likely to be found in larger systems (serving more than 10,000 people), urban systems, and systems using groundwater.

Larger water systems were nearly three times as likely to contain potentially harmful contaminants compared to smaller systems.

Further, systems with PFAS-producing industries in their areas, such as manufacturing plants, were 10 times more likely to detect PFAS in the water. 

The chemicals can linger in the body for years after being ingested, becoming lodged in bodily tissues. They can then cause inflammation and wreck havoc throughout the body.

For higher contaminant levels in urban areas and areas with a higher percentage of Hispanic Dr Maruzzo said racial disparities could not be accounted for by income or other socioeconomic factors.

He said this indicates systemic issues like racism and redlining — a discriminatory practice that withholds financial services to people in high-minority neighborhoods, something that contributed to the disproportionate placement of industrial facilities in communities of color — may be influencing the outcomes. 

The Environmental Working Group, an activist organization centered on environmental pollutants, mapped out the communities and military sites confirmed to have PFAS contamination  

The latest research builds on 2023 findings that showed areas in 18 states with a higher proportion of Hispanic and Black residents had higher levels of PFAS in their drinking water. 

Another study by researchers at Silent Spring also found Hispanic residents are more likely to be exposed to higher nitrate levels in their drinking water.

Exposure to the chemical can bind to hemoglobin in red blood cells and reduce their ability to carry oxygen, resulting in bluish skin, otherwise known as blue baby syndrome, most common in infants under six months.

Some studies also suggest a link to cancers, spontaneous abortion in pregnant women, thyroid dysfunction and heart problems.

Dr Schaider said: ‘Ultimately, we need to do a better job at protecting source waters and reducing discharges of pollutants into water bodies that feed into our drinking water supplies.’