For decades, chemicals known as per- and polyfluoroalkyl substances, or PFAS, were used in many things from carpets to frying pans to firefighting chemicals for their ability to repel water and oil. However, this was before a wide array of negative health effects ranging from cancer and low birth weights to effects on the immune system were discovered in some kinds of PFAS.
According to UANews, the Environmental Protection Agency places health-based limits on the concentration of contaminants allowed in drinking water and the federal limit for arsenic in drinking water is 10 parts per billion. The federal limit for perchloroethene, a chemical associated with several types of cancer, is 5 parts per billion. The federal health advisory limit for the sum of both PFOS and PFOA – two widely used types of PFAS – is many times more stringent at 70 parts per trillion.
"Not only are the chemicals everywhere, and bad, but the advisory level established by the EPA is so extremely low that it makes it even more challenging to treat them," said Reyes Sierra, a chemical and environmental engineering professor who is affiliated with the UA's Institute of the Environment. "The University of Arizona is doing something about it."
Using a $1.2 million grant from the U.S. Department of Defense's Strategic Environmental Research and Development Program, Reyes is leading a team in developing a new method for removing PFAS contaminants from groundwater, according to UANews.
The research is timely in light of PFAS levels of 30 parts per trillion being found in parts of Tucson's water supply in late 2018, according to the Arizona Daily Star. Thirty parts per trillion is below the EPA advisory level, however, it is almost double the level a June 2018 study by the federal Agency for Toxic Substances Disease Registry found advisable for drinking.
According to UANews, the chemicals' presence in firefighting chemicals means they often are found on military bases and in adjacent groundwater – in this case, in water wells north of Tucson's Davis-Monthan Air Force Base.