A new study by researchers at Harvard University shows that the water supplies of nearly 6 million Americans are tainted with unsafe levels of polyfluoroalkyl and perfluoroalkyl substances, or PFASs – a class of industrial chemicals linked to potentially serious health problems. 
PFASs have been used for decades in a wide variety of industrial and commercial products, including non-stick coatings on pans, food wrappers, water-repellent clothing, and firefighting foam.
Long-term exposure to PFASs has been linked to a higher risk of kidney cancer, thyroid problems, high cholesterol, and hormone disruption, among other health issues.
Xindi Hu, the study’s lead author, said:
“Virtually all Americans are exposed to these compounds. They never break down. Once they are released into the environment, they are there.”
What the Team Found in the Water
For the study, in Environmental Science and Technology Letters, researchers looked at concentrations of 6 types of PFAS chemicals in 36,000 samples of drinking water from around the U.S. that were collected by the Environmental Protection Agency (EPA) between 2013 and 2015.
Hu and his colleagues also looked at sites where PFASs are commonly found, including industrial plants that use the chemicals in manufacturing, military bases, civilian airports where firefighting foam is used, and wastewater treatment plants.
“PFASs are a group of persistent manmade chemicals that have been in use since 60 years ago. Most current wastewater treatment processes do not effectively remove PFASs.” 
The team discovered that 194 of 4,864 water supplies analyzed from nearly three dozen states had detectable levels of PFASs. Of these water supplies, 66 had at least one sample that exceeded the EPA’s recommended safety limit of 70 parts per trillion (ppt) for perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). 
Those 66 water supplies serve some 6 million people.
About 75% of the unsafe water supply came from 13 states: Alabama, Arizona, California, Florida, Georgia, Illinois, Massachusetts, Minnesota, New Jersey, New York, North Carolina, Ohio, and Pennsylvania. 
The Problem Might be Larger than We Know
But Hu fears the problem may be more widespread than the new study suggests, as researchers lacked data on drinking water from smaller public water systems and private wells that serve nearly 1/3 of the U.S. population – some 100 million people.
PFAS chemicals are not currently regulated by the federal government. However, they are on the EPA’s list of “unregulated contaminants” that are monitored by the agency, with the intent of restricting the chemicals most hazardous to humans. 
The EPA has only even come close to taking action in the 1990’s, when it almost imposed a new standard for the chemical perchlorate, which sometimes occurs naturally but also is found in explosives, road flares, and rocket fuel. It has been found in the drinking water of over 16 million people.
Joel Beauvais, who leads the EPA’s Office of Water, said the system won’t change unless Congress demands the EPA move deliberately. He explained:
“It’s a rather intensive process to get one of these drinking-water regulations across the finish line.”
(However, in January, the Food and Drug Administration (FDA) took the step of banning perfluoroalkyl, along with two other chemicals, in pizza boxes and other food packaging.)
According to Beauvais, this is because a substance may occur in only a low number of drinking-water systems or might only occur in extremely low levels. The EPA must prove that imposing regulations would benefit public health before imposing new limitations on the nation’s water utilities. Beauvais said:
“These are very consequential regulations. They are consequential from a health perspective. They are consequential from an economic perspective.”
We Need to Take Action
But the EPA can potentially prompt state and local officials to take action or at least notify residents about contaminants by issuing health advisories. For example, in May, the agency issued advisories for PFOS and PFOA, urging utilities nationwide to follow more stringent guidelines than the EPA had previously recommended.
The advisory led to one Alabama community declaring its tap water unfit to drink, and advising residents to avoid it until officials could install a temporary, high-powered filter for the water supply.
Some New Hampshire communities received bottled water while authorities determined how to tackle high levels of contaminants in nearby groundwater. And a company in upstate New York agreed to install carbon filters in private homes where testing had revealed high levels of the chemicals.
Richard Clapp, professor emeritus at Boston University’s school of public health, said he believes few people would argue against regulating PFAS compounds, in light of the mounting evidence of potential health risks associated with them. He said:
“We’re definitely overdue. It’s not a question of whether, but rather at what level should they be regulated.”
One of the potential health complications associated with PFASs appears to be altered immune function. A second Harvard study by one of the co-authors of the paper, Philippe Grandjean, looked at the issue. 
The research, published in the journal Environmental Health Perspectives, involved nearly 600 adolescents from the Faroe Islands, located off the coast of Denmark. The youngsters had received various vaccines to protect against tetanus and diphtheria.
The teens who were exposed to PFASs at a young age had lower-than-expected levels of antibodies against diphtheria and tetanus despite receiving vaccinations.
The findings suggest that PFASs, known to interfere with immune function, may play a role in reducing the effectiveness of vaccines in children.
In earlier studies, researchers found lower responses to vaccinations at ages 5 and 7 with exposure to PFASs. The current study in adolescents suggests that this problem persists as children get older.