Declining concentrations of chlorinated paraffins in endangered St. Lawrence Estuary belugas (Delphinapterus leucas): Response to regulations or a change in diet?

Simond, Antoine E.; Ross, Peter S.; Cabrol, Jory; Lesage, Véronique; Lair, Stéphane; Woudneh, Million B.; Yang, Diwen; Peng, Hui; Colbourne, Katerina; Brown, Tanya M.

doi:10.1016/j.scitotenv.2023.161488

Cited by 5 publications

(4 citation statements)

References 55 publications

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“…In contrast to the SHB subpopulation in our study and in another study of beluga whales, 14 the WHB subpopulation showed an upward PCA trend. The levels of PCAs eventually surpassed those in the SHB as of 2020/2021, when the highest levels of FA tracers were observed.…”

Section: ■ Resultscontrasting

confidence: 99%

“…The decreasing PCA trends of the SHB subpopulation mirrored those reported in St. Lawrence Estuary beluga whales, 14 indicative of accumulation through the regional marine food web. The SHB polar bears of the sampling period consistently showed higher levels of PCAs-C 10−13 (average of 43.5 ng/g of lipid) and PCAs-C 14−17 (65.8 ng/g of lipid) compared to those of beluga whales, which averaged versus 29.1 and 24.6 ng/g of lipid, respectively.…”

Section: ■ Resultssupporting

confidence: 59%

“…Despite this long history and increasing trends, information about PCAs in the continent’s natural environments is limited, with research focusing primarily on marine biota , and an almost complete absence of data on PCAs-C >17 and PCAs-C 6–9 . Recent data from the St. Lawrence Estuary’s beluga whales ( Delphinapterus leucas ) indicated a declining trend of PCAs by 2018, predominantly PCAs-C 10–13 , and PCAs-C >17 was not detectable in any of the samples . This scenario underscores a significant knowledge gap in understanding PCA contamination in terrestrial biota, where there is a stronger tendency for PCA accumulation.…”

Section: Introductionmentioning

confidence: 94%

“…1 Despite this long history and increasing trends, information about PCAs in the continent's natural environments is limited, with research focusing primarily on marine biota 12,13 PCAs-C 10−13 , and PCAs-C >17 was not detectable in any of the samples. 14 This scenario underscores a significant knowledge gap in understanding PCA contamination in terrestrial biota, where there is a stronger tendency for PCA accumulation.…”

Section: ■ Introductionmentioning

confidence: 98%

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Evolving Accumulation of a Complex Profile of Polychlorinated Alkanes in Canadian Polar Bears

Yuan,

Letcher

2024

Environ. Sci. Technol. Lett.

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Approximately 33 million t of polychlorinated alkanes (PCAs), also known as chlorinated paraffins, has been globally produced and used. Despite the higher bioaccumulation potential of PCAs in terrestrial ecosystems than in marine ecosystems, North American terrestrial PCA data are sparse and Arctic studies largely focus on short-chain PCAs, with minimal attention to longer-chain homologues in wildlife. This research delves into the dynamics of PCA accumulation and temporal changes across a broad spectrum of PCA homologues in polar bears (Ursus maritimus) from Hudson Bay. Subcutaneous fat samples collected over the past decade from adult male polar bears of the Western Hudson Bay (WHB) and Southern Hudson Bay (SHB) subpopulations were analyzed, identifying 109 of 545 PCA homologues, ranging from C 8 to C 26 . Analysis of 37 dietary fatty acids provided insights into dietary shifts and their influence on PCA profiles. Notably, SHB bears exhibited a decrease in PCA concentrations, reflecting marine food web influences. In contrast, WHB bears displayed increasing PCA levels, likely due to the use of more terrestrial and anthropogenic food sources. This study underscores the critical yet overlooked role of longer-chain PCAs in the Arctic food web and polar bear exposure, emphasizing the variance between subpopulations and the significant impact of dietary factors.

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Section: ■ Resultscontrasting

confidence: 99%

Section: ■ Resultssupporting

confidence: 59%