Effects of Polar Bear and Killer Whale Derived Contaminant Cocktails on Marine Mammal Immunity

Most controlled toxicity studies use single chemical exposures that do not represent the real world situation of complex mixtures of known and unknown natural and anthropogenic substances. In the present study, complex contaminant cocktails derived from the blubber of polar bears (PB; Ursus maritimu...

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Bibliographic Details
Published in:Environmental Science & Technology
Main Authors: Desforges, Jean Pierre, Levin, Milton, Jasperse, Lindsay, De Guise, Sylvain, Eulaers, Igor, Letcher, Robert J., Acquarone, Mario, Nordøy, Erling, Folkow, Lars P., Hammer Jensen, Trine, Grøndahl, Carsten, Bertelsen, Mads F., St Leger, Judy, Almunia, Javier, Sonne, Christian, Dietz, Rune
Format: Article in Journal/Newspaper
Language:English
Published: 2017
Subjects:
Killer Whale
Orca
Orcinus orca
Ursus maritimus
Killer whale
Online Access:https://vbn.aau.dk/da/publications/86c2d5ae-5963-40a3-92de-6741b66b1b1c
https://doi.org/10.1021/acs.est.7b03532
http://www.scopus.com/inward/record.url?scp=85030678455&partnerID=8YFLogxK
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Summary:Most controlled toxicity studies use single chemical exposures that do not represent the real world situation of complex mixtures of known and unknown natural and anthropogenic substances. In the present study, complex contaminant cocktails derived from the blubber of polar bears (PB; Ursus maritimus) and killer whales (KW; Orcinus orca) were used for in vitro concentration-response experiments with PB, cetacean and seal spp. immune cells to evaluate the effect of realistic contaminant mixtures on various immune functions. Cytotoxic effects of the PB cocktail occurred at lower concentrations than the KW cocktail (1 vs 16 μg/mL), likely due to differences in contaminant profiles in the mixtures derived from the adipose of each species. Similarly, significant reduction of lymphocyte proliferation occurred at much lower exposures in the PB cocktail (EC 50 : 0.94 vs 6.06 μg/mL; P < 0.01), whereas the KW cocktail caused a much faster decline in proliferation (slope: 2.9 vs 1.7; P = 0.04). Only the KW cocktail modulated natural killer (NK) cell activity and neutrophil and monocyte phagocytosis in a concentration- and species-dependent manner. No clear sensitivity differences emerged when comparing cetaceans, seals and PB. Our results showing lower effect levels for complex mixtures relative to single compounds suggest that previous risk assessments underestimate the effects of real world contaminant exposure on immunity. Our results using blubber-derived contaminant cocktails add realism to in vitro exposure experiments and confirm the immunotoxic risk marine mammals face from exposure to complex mixtures of environmental contaminants.

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