Unique hepatic maternal transfer pattern of trace metals and perfluoroalkyl substances (PFAS) in a bluntnose sixgill shark (Hexanchus griseus)

Misha Zvekic; Holly Barrett; Peter Diamente; Hui Peng; Erik T Krogh

doi:10.1016/j.chemosphere.2024.142315

Unique hepatic maternal transfer pattern of trace metals and perfluoroalkyl substances (PFAS) in a bluntnose sixgill shark (Hexanchus griseus)

Chemosphere. 2024 May 10:359:142315. doi: 10.1016/j.chemosphere.2024.142315. Online ahead of print.

Authors

Misha Zvekic¹, Holly Barrett², Peter Diamente³, Hui Peng², Erik T Krogh⁴

Affiliations

¹ Applied Environmental Research Laboratories (AERL), Department of Chemistry, Vancouver Island University, Nanaimo, V9R 5S5, British Columbia, Canada; Department of Chemistry, University of Victoria, Victoria, V8P 5C2, British Columbia, Canada.
² Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
³ Applied Environmental Research Laboratories (AERL), Department of Chemistry, Vancouver Island University, Nanaimo, V9R 5S5, British Columbia, Canada.
⁴ Applied Environmental Research Laboratories (AERL), Department of Chemistry, Vancouver Island University, Nanaimo, V9R 5S5, British Columbia, Canada; Department of Chemistry, University of Victoria, Victoria, V8P 5C2, British Columbia, Canada. Electronic address: Erik.Krogh@viu.ca.

PMID: 38735494
DOI: 10.1016/j.chemosphere.2024.142315

Abstract

The fate and distribution of environmental contaminants includes bioaccumulation within marine organisms. A deceased 4-m long adult female bluntnose sixgill shark, pregnant with 72 pups, was recovered from Coles Bay on Vancouver Island, BC, Canada in 2019. This specimen provided a unique opportunity to examine maternal transfer of contaminants in a yolk-sac viviparous shark species. Liver subsamples of the adult and offspring were analyzed for 18 targeted inorganic elements by inductively coupled plasma optical emission spectroscopy (ICP-OES) and 21 targeted perfluoroalkyl substances (PFAS) by liquid chromatography-electrospray ionization-high resolution mass spectrometry (LC-ESI-Orbitrap MS). The maternal-offspring transfer efficiencies in liver tissue were subsequently examined for both contaminant classes. Concentrations of all detectable metals apart from calcium and magnesium were found to be higher in the mother compared to the offspring, including substantial levels of toxic cadmium (6 ± 2 mg kg^-1 dw) and lead (7 ± 3 mg kg^-1 dw). Conversely, high maternal transfer efficiencies were observed for PFAS (i.e., ΣPFAS = 71 ± 9 ng g^-1 ww in offspring compared to 13 ± 9 ng g^-1 ww in the mother). This study highlighted the unique maternal transfer characteristics of PFAS in bluntnose sixgill sharks depending on the structure of the polar head group, with greater liver-to-liver transfer efficiencies observed for perfluorocarboxylic acids (PFCAs) than perfluorosulfonic acids (PFSAs) of the same fluorocarbon chain length.

Keywords: Forever chemicals; Heavy metals; Lecithotrophic; Marine contaminants; Ovoviviparous; Persistent organic pollutants; Trace contaminants.