Detection of PFAS in canines and equines residing in the vicinity of Fayetteville, NC.

June 21, 2023

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by North Carolina State University

In a new study conducted by researchers from North Carolina State University, elevated PFAS levels were found in the blood of pet dogs and horses from Gray's Creek, N.C. This includes dogs that only drank bottled water. The work establishes horses as an important sentinel species and is a step towards 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 request of community members who were concerned about their pets' well-being. All households in the study were on well water, and all wells had been tested and deemed PFAS contaminated by state inspectors.

The animals underwent a general veterinary health check and had their blood serum screened for 33 different PFAS chemicals. These PFAS were chosen based on compounds found in the Cape Fear River basin and the availability of analytical standards.

Researchers found 20 different PFAS in the animals from the targeted list of 33 PFAS of interest. All of the animals in the study had at least one chemical detected in their blood serum, and over 50% of the dogs and horses had at least 12 of the 20 detected PFAS. PFOS had the highest concentrations in dog serum. PFHxS, a surfactant used in consumer products and firefighting foams, was detected in dogs but not horses. Ether-containing PFAS including HFPO-DA were detected only in dogs and horses that drank well water.

Median concentrations of PFOS and PFHxS were similar to those of children in the Wilmington GenX exposure study in dogs who drank well water, suggesting that pet dogs may serve as an important indicator of household PFAS. Interestingly, dogs who drank bottled water had different types of PFAS in their blood serum. However, 16 out of the 20 PFAS detected in this study were found in dogs who drank bottled water.

Horses showed lower concentrations of PFAS than dogs but had 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.

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

The veterinary blood chemistry panels for the animals showed changes in diagnostic biomarkers used to assess liver and kidney dysfunction, two organ systems that are 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 and corresponding author of the work.

'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,' Belcher says. '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 work, titled 'Domestic Dogs and Horses as Sentinels of Per- and Polyfluoroalkyl Substance (PFAS) Exposure and Associated Health Biomarkers in Gray's Creek North Carolina,' appears in Environmental Science and Technology.

More information: Domestic Dogs and Horses as Sentinels of Per- and Polyfluoroalkyl Substance (PFAS) Exposure and Associated Health Biomarkers in Gray's Creek North Carolina, Environmental Science & Technology (2023). DOI: 10.1021/acs.est.3c01146

Journal information: Environmental Science & Technology , Environmental Science and Technology

Provided by North Carolina State University