By Study Finds

Chemicals found in everything from cleaning products to stain-resistant carpets could be harming our pets. In a groundbreaking study, scientists from North Carolina State University discovered elevated levels of PFAS – chemicals that resist grease, oil, water, and heat – in the blood of pet dogs and horses from Gray’s Creek, N.C., even among dogs that exclusively drank bottled water.

This research not only highlights the significance of horses as sentinel species but also takes us closer to understanding the potential impact of PFAS exposure on the liver and kidney function of dogs and horses.

The study involved 31 dogs and 32 horses from the community, following concerns raised by local members about the health of their pets. All the households included in the study relied on well water, which had been previously identified as contaminated with PFAS by state inspectors.

During the research, the animals underwent general veterinary health check-ups, and their blood serum was screened for 33 different PFAS chemicals. The selection of these PFAS compounds was based on their presence in the Cape Fear River basin and the availability of analytical standards.

Among the targeted PFAS compounds, the researchers identified 20 different chemicals in the animals. Every single animal in the study had at least one PFAS detected in their blood serum, with over 50 percent of dogs and horses having a minimum of 12 out of the 20 PFAS detected.

In terms of concentrations, PFOS, a long-chain PFAS commonly used in industrial and commercial products, showed the highest levels in dog serum. The surfactant PFHxS, used in consumer products and firefighting foams, was detected in dogs but not in horses. Interestingly, certain ether-containing PFAS, including HFPO-DA (known as GenX), were only found in dogs and horses that consumed well water, confirming the wells as the known source of contamination.

Dogs that consumed well water exhibited median concentrations of two PFAS compounds – PFOS and PFHxS – similar to those found in children during the Wilmington GenX exposure study. This suggests that pet dogs could serve as important indicators of household PFAS contamination. On the other hand, dogs that consumed bottled water had different types of PFAS in their blood serum, although 16 out of the 20 PFAS detected in the study were also present in these dogs.

Overall, horses showed lower concentrations of PFAS compared to dogs. However, they displayed higher levels of Nafion byproduct 2 (NBP2), a byproduct of fluorochemical manufacturing. This finding indicates that environmental contamination, potentially from PFAS deposition on forage, contributed to their exposure.

“Horses have not previously been used to monitor PFAS exposure,” says Kylie Rock, postdoctoral researcher at NC State, in a university release. “But they may provide critical information about routes of exposure from the outdoor environment when they reside in close proximity to known contamination sources.”

Furthermore, the veterinary blood chemistry panels conducted on the animals revealed changes in diagnostic biomarkers used to assess liver and kidney function, which are known to be primary targets of PFAS toxicity in humans.

“While the exposures that we found were generally low, we did see differences in concentration and composition for animals that live indoors versus outside,” says Scott Belcher, associate professor of biology at NC State. “The fact that some of the concentrations in dogs are similar to those in children reinforces the fact that dogs are important in-home sentinels for these contaminants. And the fact that PFAS is still present in animals that don’t drink well water points to other sources of contamination within homes, such as household dust or food.”

The study is published in the journal Environmental Science and Technology.