Industrial chemicals are in a lot of things: nonstick cookware, clothing, cosmetics, firefighting foam, the list goes on. One particular family, per- and polyfluoroalkyl substances (PFAS), are both everywhere and potentially harmful in high concentrations. And now, scientists have found these chemicals in household pets, too.
Researchers at the New York State Department of Health tested the feces of cats and dogs for the presence of 15 different kinds of PFAS and found measurable traces of 13 of these so-called “forever chemicals.” What’s more, the traces of chemicals found indicate that the pets—and by extension their human owners—had been exposed to some PFAS at levels above the accepted minima for humans.
“The estimated daily fecal excretion suggested that both dogs and cats are exposed to some PFASs at doses above the provisional minimum risk level recommended for humans,” the authors concluded in their study. That all but two of the chemicals tested for were detected suggests “widespread exposure of pets to PFASs.”
They published their findings on Wednesday in the journal Environmental Science & Technology Letters, an American Chemical Society publication.
PFAS are a family of man-made chemicals that have been used since the 1950s due to their durability and resistance to heat, oil, and water. This ability comes from their chemical makeup: long chains of carbon atoms bonded to fluorine atoms. Because of the strength of a carbon-fluorine bond, PFAS do not easily degrade in the environment, leading to the nickname "forever chemicals."
Although the use of PFAS in the U.S. has declined since 2002, the chemicals have been found in drinking water across the country. Studies of some PFAS suggest that at high concentrations, they may increase cancer risk, interfere with hormones, and affect the immune system. PFAS exposure may harm non-humans, too: in the study, the authors cited research on laboratory animals showing that PFAS had toxic effects on their livers, brains, and genes.
According to the study, the collection and analysis of human feces for PFAS can be “demanding,” which is why pets may be a good stand-in.
“Pets such as dogs and cats share a common living environment with humans and have been used as sentinels of human exposure to environmental contaminants, including PFASs,” the authors wrote in the study.
Kannan and his team collected 41 fecal samples from cats and 37 from dogs living in the Albany area. After grinding them with a porcelain mortar and pestle, they subjected the samples to rigorous chemical testing.
The authors found an average of 54.7 nanograms of PFAS per gram of dry feces for dogs, and 85.4 nanograms per gram of feces for cats. Age and gender did not affect the concentrations of the chemicals in the pets.
It is unclear how the pets in Kannan’s study were exposed to PFAS, though the chemicals can be taken in by ingesting, inhaling, or touching them. Once in the body, the chemicals are mostly concentrated in the blood, liver, and kidneys. Some of the first inklings that PFAS may be harmful came when cows began dying on a West Virginia ranch. A nearby creek was later found to have been polluted by tons of chemicals from the local DuPont plant. Animals may once again be an early sign of PFAS exposure.