Key points:
- Researchers found 20 PFAS chemicals in pet dogs and horses living in North Carolina.
- The medium concentration of two PFAS in dogs was similar to that of children living in the area.
- The work establishes horses as an important sentinel species.
Researchers from North Carolina State University detected elevated PFAS levels in the blood of pet dogs and horses from Gray’s Creek, N.C., including dogs that only drank bottled water. The work establishes horses as an important sentinel species and is a step toward investigating connections between PFAS exposure and liver and kidney function in dogs and horses.
The study included 31 dogs and 32 horses from the community, and was conducted at the behest of community members concerned about their pets’ well-being. All of the households in the study were on well water, and all of the wells had been tested and deemed PFAS-contaminated by state inspectors.
The animals had their blood serum screened for 33 different PFAS chemicals chosen based on compounds present in the Cape Fear River basin.
According to the results, published in Environmental Science & Technology, of the targeted 33, researchers found 20 different PFAS chemicals in the animals. Every single animal was positive for at least one, while at least 50% had a minimum of 12 PFAS.
PFOS, a long-chain PFAS used for years in industrial and commercial products, had the highest concentrations in dog serum. The perfluorosulfonic acid PFHxS, a surfactant used in consumer products and firefighting foams, was detected in dogs, but not horses. Consistent with wells being the known contamination source, some ether-containing PFAS including HFPO-DA (colloquially known as GenX), were detected only in dogs and horses that drank well water.
In dogs who drank well water, median concentrations of two of the PFAS – PFOS and PFHxS –were similar to those of children in the Wilmington GenX exposure study, suggesting that pet dogs may serve as an important indicator of household PFAS. Dogs who drank bottled water, on the other hand, had different types of PFAS in their blood serum. However, 16 out of the 20 PFAS detected in this study were found in the dogs who drank bottled water.
Overall, horses had lower concentrations of PFAS than dogs, though the horses did show higher concentrations of Nafion byproduct 2 (NBP2), a byproduct of fluorochemical manufacturing. The finding suggests that contamination of the outdoor environment, potentially from deposition of the PFAS onto forage, contributed to their exposure.