Bioaccumulation of polyfluoroalkyl substances in the Lake Huron aquatic food web

Polyfluoroalkyl substances (PFAS) are a group of fluorinated organic chemicals that have been produced for industrial and commercial application since the 1950s. PFAS are highly persistent and ubiquitous in water, sediment, and biota. Toxic effects of PFAS on humans and the ecosystem have increased scientific and public concern. To better understand the distribution of PFAS in the Laurentian Great Lakes, carbon (¹²C and ¹³C) and nitrogen (¹⁴N and ¹⁵N) stable isotope enrichment, fatty acid profiles, and PFAS were measured in the Lake Huron (LH) aquatic food web. The trophic level of the organisms was estimated using δ¹⁵N and found to be a determinant of PFAS biomagnification. The δ¹³C and fatty acid profiles were used to assess the carbon/energy flow pathway and predator-prey relationships, respectively. The δ¹³C, δ¹⁵N, and fatty acids were used to elucidate the trophodynamics and understand the PFAS trophic transfer in the LH aquatic food web. Perfluorooctanesulfonic acid (PFOS) was the dominant PFAS observed, followed by C9 - C11 perfluorinated carboxylic acids (PFCA). The highest PFOS concentrations (45 ± 11 ng/g, wet weight (wwt)) were detected in lake trout (Salvelinus namaycush), while the highest total PFCA concentrations (sum of C4 - C16 PFCAs) were detected in deepwater sculpin (Myoxocephalus thompsonii). With the exception of perfluorooctanoic acid (PFOA), C8-C14 PFAS biomagnification factors (BMFs) were found to be generally greater than 1, suggesting PFAS biomagnification from prey to predator. Trophic magnification factors (TMFs) of C8-C14 PFCA were found to be independent of compound hydrophobicity.