Water is essential for life, but contaminants can put people at risk of cancer and other disease. Now a new report has discovered cancer-causing industrial chemicals may be present in the drinking water of six million people across the United States.
The study comes from Xindi Hu and other researchers at the Harvard T.H. Chan School of Public Health and the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS). The study authors published their findings August 9th in the journal Environmental Science and Technology Letters. Since polyfluoroalkyl and perfluoroalkyl substances (PFASs) are common industrial chemicals, and they are linked to cancer and other health problems, the researchers wanted to discover just how prevalent these chemicals are in drinking water across the country.
For their study, the researchers examined data from 36,000 water samples collected between 2013 and 2015 by the U.S. Environmental Protection Agency (EPA). These samples were from locations across the country. The researchers also looked at locations that may have PFASs, such as industrial properties where companies are either making or using the chemicals; civilian airports and military fire training sites that use fire-fighting foam that contains PFASs; and wastewater treatment plants. PFASs from all these locations could enter the groundwater, either directly or through the use of sludge from industrial plants for fertilizer. This contaminated water is then taken up for use in the public water supply.
The EPA has a minimum level of PFAS that needs to be reported in groundwater. Out of 4,864 water supplies across 33 states, 194 of them met or exceeded these levels set by the EPA. About 75% of these water supplies with PFAS were in just 13 states, with the highest frequency in California. After that came New Jersey, North Carolina, Alabama, Florida, Pennsylvania, Ohio, New York, Georgia, Minnesota, Arizona, Massachusetts, and Illinois.
According to EPA standards, the safety limit for PFASs in the water supply is 70 parts per trillion (ng/L). Of the public water supplies studied, sixty-six had at least one water sample meeting or exceeding this safety limit. The highest concentration was in Newark, Delaware, which had 1,800 ng/L of PFOS, which is perfluorooctanesulfonic acid. The next highest concentration was in Warminster, Pennsylvania, with 349 ng/L of PFOA, which is perfluorooctanoic acid. Not surprisingly, when the authors examined the locations with the highest levels of PFAS in the water supply, these were watersheds near military bases, industrial sites, and wastewater treatment plants that may be releasing these chemicals into the environment.
The biggest concern is that the sixty-six water supplies with unsafe levels of PFASs provide drinking water to six million people. These people are exposed to cancer-causing chemicals every day just drinking, cooking with, or bathing in water in their own home. Even more concerning is that PFAS data is missing for the drinking water of about 100 million people, about a third of the country’s population. There is no telling how many of these people also face high levels of PFAS.
These chemicals have been around for about sixty years, and although many major manufacturers have stopped using PFASs, they persist in the environment and people continue to be exposed through drinking water and other sources. It seems that although the EPA is warning of the dangers of PFAS, everyone is still living with the legacy of six decades of use.
PFAS chemicals are used in a wide variety of consumer products, such as food wrappers, clothing, carpets and upholstery, and Teflon cooking pots, and they are also used industrially and in firefighting foam. The chemicals are useful for their resistance to heat, water, and oil and they have hundreds of applications. PFAS tend not to degrade easily, so they tend to persist in the environment and accumulate in the blood and organs of humans and other animals. Over time, this bioaccumulation means that people and animals will have higher and higher concentrations of these chemicals in their body.
Previous studies using laboratory animals found that exposure to high concentrations of certain PFASs are linked to health problems such as high cholesterol, low birth weight, delayed puberty, and poor response to vaccination. Other human studies have suggested PFAS chemicals could be linked to prostate, kidney, or testicular cancer; developmental delays; hormone disruption; decreased fertility; changes to liver enzymes and the immune system; and increased uric acid. Some have also suggested a link between PFAS and obesity.
Unfortunately, there is not much that people can do to reduce their exposure to PFAS, since it persists in the environment and in the water supply. They can avoid eating fish caught in areas with high PFAS levels, but most consumer products are already reducing the use of PFAS. Wastewater treatment plants also have difficulty removing PFASs before discharging their water into the environment, so only technological developments could reduce this PFAS source. It seems the damage may already be done, but monitoring the presence of PFAS in drinking water and examining its effect on human health may help cope with six decades of using this chemical.