Timothy Phillips, Ph.D.
Texas A&M University
Edible nutrient-amended sorbents can reduce bioavailability and toxicity of per- and polyfluoroalkyl substances (PFAS) ingested via contaminated water and food, found NIEHS grantees. Clay-based sorbents bind toxins in the stomach and intestine, thereby reducing exposure. Here, the researchers tested whether adding the common nutrients carnitine and choline to a clay-based sorbent would enhance PFAS adsorption.
The researchers performed adsorption tests for common PFAS chemicals under conditions simulating the human stomach. For two of the four PFAS — PFOA, PFOS — and a mixture of those two, both nutrient-amended sorbents enhanced binding capacity, compared with the parent sorbent without nutrients. To test whether the chemicals would remain bound to the sorbents throughout the digestion process, they added PFAS-loaded sorbents to a simulated intestine environment. Only small amount of bound PFAS dissociated from the nutrient-amended sorbents, suggesting the chemicals would remain stable and tightly bind PFAS in the human intestine.
To test the safety and efficacy of the sorbents, the researchers exposed a freshwater organism called a hydra to PFOA, PFOS, and the sorbents. They assessed hydra structural defects to determine PFAS toxicity. Compared to the parent sorbent, both nutrient-amended sorbents significantly protected hydra from PFOA and PFOS toxicity. Additionally, a mixture of the nutrient-amended sorbents provided more protection than either sorbent alone and delivered the highest protection against a PFAS mixture. According to the authors, results show that including these nutrient-amended sorbents in the diet can reduce exposure and related toxicity from PFAS-contaminated food and water.
Citation: Wang M, Orr AA, Jakubowski JM, Bird KE, Casey CM, Hearon SE, Tamamis P, Phillips TD. 2021. Enhanced adsorption of per- and polyfluoroalkyl substances (PFAS) by edible, nutrient-amended montmorillonite clays. Water Res. 188:116534.