Blubber-depth distribution and bioaccumulation of PCBs and organochlorine pesticides in Arctic-invading killer whales

• Published in: Science of The Total Environment
• Main Authors: Pedro, Sara, Boba, Conor, Dietz, Rune, Sonne, Christian, Rosing-Asvid, Aqqalu, Hansen, Martin, Provatas, Anthony, McKinney, Melissa A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: Stratification; Persistent organic contaminants; Orca; Biopsy; Transplacental transfer; IN-VITRO EXPOSURE; ORCINUS-ORCA; POLYCHLORINATED-BIPHENYLS; MARINE MAMMALS; STABLE-ISOTOPE; BALEEN WHALES; FATTY-ACIDS; CONTAMINANTS; ECOLOGY; Arctic; Faroe Islands; Greenland; baleen whales; greenlandic; North Atlantic; Orcinus orca; Sea ice
• Online Access: https://pure.au.dk/portal/da/publications/blubberdepth-distribution-and-bioaccumulation-of-pcbs-and-organochlorine-pesticides-in-arcticinvading-killer-whales(9950599e-b4f9-45f0-bad2-2f0865951c89).html; https://doi.org/10.1016/j.scitotenv.2017.05.193

Sightings of killerwhales (Orcinus orca) in Greenland have increased in recent years, coincidentwith sea ice loss. These killerwhales are likely from fish-feeding North Atlantic populations, but may have access tomarinemammal prey in Greenlandic waters, which could lead to increased exposures to biomagnifying contaminants. Most studies on polychlorinated biphenyl (Sigma PCB) and organochlorine (OC) contaminants in killerwhales have used biopsies which may not be representative of contaminant concentrations through the entire blubber depth. Here, we measured PCB and OC concentrations in 10 equal-length blubber sections of 18 killer whales harvested in southeast Greenland (2012-2014), and 3 stranded in the Faroe Islands (2008) and Denmark (2005). Overall, very high concentrations of Sigma PCB, Schlordanes (Sigma CHL), and Sdichlorodiphenyltrichloroethane (Sigma DDT) were found in the southeast Greenland and Denmark individuals (means of similar to 40 to 70 mg kg(-1) lipid weight). These concentrations were higher than in the Faroe Island individuals (means of similar to 2 to 5 mg kg(-1) lipid weight) and above those previously reported for other fish-feeding killerwhales in the North Atlantic, likely in part due to additional feeding onmarinemammals. On a wetweight basis, concentrations of all contaminants were significantly lower in the outermost blubber layer (0.15-0.65 cm) compared to all other layers (p <0.01), except for Sigma hexachlorocyclohexanes. However, after lipid correction, no variationwas found for Sigma CHL and Sigma chlorobenzene concentrations, while the outermost layer(s) still showed significantly lower SPCB, SDDT, Smirex, Sendosulfan, and dieldrin concentrations than one or more of the inner layers. Yet, the magnitude of these differenceswas low (up to 2-fold) suggesting that a typical biopsy may be a reasonable representation of the PCB and OC concentrations reported in killer whales, at least on a lipid weight basis. (C) 2017 Elsevier B.V. All rights reserved.