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95% of U.S. drinking water contains unsafe levels of toxic contaminants

Contamination in U.S. drinking water exposes millions of Americans to health risks, including cancer, according to a new study led by Johnnye Lewis of the University of New Mexico (UNM). In collaboration with scientists from various parts of the country, Lewis warns that drinking water from many wells and community water systems contains unsafe levels of toxic contaminants.

While many Americans believe the water from their taps is unpolluted and safe for consumption, this research suggests this is not always the case. 

Alarmingly, the experts report that people living in tribal areas or underserved communities are at a higher risk. The research also raises concerns about the exacerbating effects of climate change on sourcing safe drinking water.

Focus of the study 

The researchers investigated the presence of seven contaminants frequently found in drinking water: arsenic, fracking fluids, lead, nitrates, chlorinated disinfection byproducts, synthetic chemicals (specifically PFAS or per- and polyfluoroalkyl substances), and uranium.

“There were several of us that have expertise in dealing with these particular contaminants, and we were seeing that they’re not always at safe levels in drinking water sources for a number of reasons,” said Lewis.

Several of the contaminants, such as arsenic, uranium, lead, and nitrates, are known or suspected to cause cancer. Prolonged exposure to many of these contaminants has also been associated with neurological and developmental disorders.

“Some of these, like uranium and arsenic – and even nitrates – are just common,” Lewis said. “They commonly occur in groundwater, and sometimes it is the source that you have access to.”

Emerging new threats

On the other hand, chemicals such as fracking fluids and PFAS, which are human-induced, are emerging as new threats. Notably, PFAS, due to its nature, can persist in the environment for extended periods without breaking down.

The research emphasizes that the identified seven contaminants are just a drop in the bucket. Thousands of chemical agents potentially pollute drinking water, and the possibility of their combined effects poses further threats.

“We’re only really now starting to come up with good methods to assess what those mixtures do,” said Lewis. “There’s always a lot of uncertainty, because a mixture is not the same in one community as it is in the next.”

Public water systems 

The report highlights the varying capacities of water systems in detecting and eliminating these contaminants. Of the 150,000 public water systems in the United States, about a third are community water systems that cater to 320 million Americans – a staggering 95% of the population. 

A significant 91% of these community water systems provide for fewer than 10,000 individuals, which amounts to 52 million people. Meanwhile, over 43 million Americans depend on private wells for their drinking water.

With these findings, the authors stress the urgent need for enhancing the nation’s drinking water infrastructure, solidifying water standards, advancing water treatment procedures, and enforcing more rigorous chemical safety tests.

Study implications 

Highlighting the broader implications, Lewis pointed out that the changing climate, especially in the western U.S., is complicating the quest for clean water sources. 

“For me the thing that is most concerning is that you start looking at drought and the stresses that that puts on looking for additional water sources,” said Lewis. “The potential for making sure those sources are clean could become more limited.”

The impact of climate change will most heavily burden those who are least equipped to handle it, such as people living in communities with minimal or no water monitoring.

“When we talk about racial injustice and societal injustice in communities that are underserved, they’re the ones that are going to bear the brunt of this,” said Lewis. 

The study is published in the Journal of Exposure Science and Environmental Epidemiology.

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