We always get up to interesting work in our beautiful corner of the world in the Pacific Northwest off the Salish Sea! This study (Lee et al. 2023) from the University of British Columbia and Fisheries and Oceans Canada is especially topical as it tracks the sources, and maternal transfer of Polycyclic Aromatic Compounds (PACs or PAHs) in our beloved Orca (Killer Whale) populations, both the threatened Southern residents (SRKW) and the Biggs. It features PAH data in the Orca that SGS AXYS generated using our exceptional PAC measurement capabilities.
This study provided the first evidence of PAH contamination in skeletal muscle and liver samples of stranded SRKWs and Bigg’s killer whales inhabiting the NEP waters of British Columbia,
Interesting findings from the study (Open access full text published in Nature Scientific Reports)
- “Accounting for 33.48% of the total contamination across all samples was C3-phenanthrenes/anthracenes followed by C4-dibenzothiophenes (17.7%) and C4-phenanthrenes/anthracenes (13.1%)”. Note these are all part of extended PAC lists and would be missed if you were only measuring the standard list of priority PAHs.
- “Overall, liver samples of Bigg’s killer whales had a predominantly pyrogenic PAH profile whereas in SRKWs, PAHs were primarily sourced from petrogenic origins”. This is fascinating and points to the “habitat range, prey selection, and metabolism” as differentiating factors. The Northeast Pacific (NEP) waters where the critically endangered southern residents live are busy with industrial and marine activity and the authors point to oil spills/discharges as being a potential source of these petrogenic PAHs in the SRKW.
- “Our data show efficient and preferential contaminant exposure (MTR > 1) to the fetus in 16 PAH compounds, with the three highest ratios being C3-fluorenes (26.3), dibenzothiophene (8.0), and naphthalene”. Maternal transfer is a common phenomenon observed for non-polar lipophilic pollutants where the contaminants are transferred from mother to baby through milk. This is a significant risk to newborns and young as they are much more vulnerable to toxic contaminants than adults are.
SGS AXYS’ capabilities on PACs and PAHs are unique and well-suited for challenging work.
- Our long list includes 70+ priority PAHs, alkylated PAHs and other Polycyclic Aromatic Compounds (PACs) including parent and substituted thiophenes that enables source identification, especially differentiating between pyrogenic (combustion-related) and petrogenic (arising from fossil fuel extraction/sources).
- Our extensive sample preparation/cleanup procedures ensure high-quality and high sensitivity data in challenging tissue samples such as whale liver and more
We are happy to see this study published, even if it points to some concerning trends. As the authors summarize:
Our results show that hydrocarbon-related anthropogenic activities are negatively impacting these top predators; preliminary data found here can be used to improve oil spill and other PAH pollution management and regulation efforts, and inform policy to conserve killer whale habitats in the NEP.
References
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Lee, K. et al. (2023) ‘Polycyclic aromatic hydrocarbon (PAH) source identification and a maternal transfer case study in threatened killer whales (Orcinus orca) of British Columbia, Canada’, Scientific Reports, 13(1), p. 22580. Available at: https://doi.org/10.1038/s41598-023-45306-w.
