PFAS Occurrence in Water, Sediment, and Chironomid Larvae in the Central Basin of Lake Erie

Abstract

Per- and polyfluoroalkyl substances (PFAS) are persistent contaminants of emerging concern in the Laurentian Great Lakes, yet pathways of their transfer through aquatic food webs remain poorly understood. Chironomid midges, which are abundant in Lake Erie sediments and a key food source for fish and birds, may facilitate the transfer of PFAS from benthic sediments to higher trophic levels in aquatic and terrestrial ecosystems. We assessed the presence and concentrations of a suite of PFAS in surface water, sediment, and chironomid larvae collected from the Central Basin of Lake Erie and assessed whether concentrations change with increasing distance from shore. Sediment exhibited the highest total PFAS concentrations (mean ± SE = 88.93 ± 41.21 ng/g d.w.), with PFOS being the dominant compound. Water samples had a total PFAS concentration of 19.42 ± 3.55 ng/L, dominated by PFOA and PFOS. In contrast, chironomid larvae had comparatively low total PFAS body burdens (0.55 ± 0.13 ng/g d.w.), and like sediment, were dominated by PFOS. Biota-sediment accumulation factors (BSAFs) for midges were low (0.01 ± 0.007) PFAS concentrations in water, sediment, and midges varied with distance from shore, with inshore and midshore locations showing higher concentrations than offshore locations. Multivariate analysis revealed that PFAS profiles differed between water and sediment and that water profiles differed with distance from shore. Our findings demonstrate that chironomids in Lake Erie contain detectable PFOS concentrations, although at substantially lower levels than nearby sediments. However, their high abundance and ecological importance as prey suggest they may contribute to PFAS transfer between benthic, pelagic, and nearshore terrestrial food webs.

Keywords: Bioaccumulation, Forever Chemicals, Food Chain