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

Sara Pedro; Conor Boba; Rune Dietz; Christian Sonne; Aqqalu Rosing-Asvid; Martin Hansen; Anthony Provatas; Melissa A McKinney

doi:10.1016/j.scitotenv.2017.05.193

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

Sci Total Environ. 2017 Dec 1:601-602:237-246. doi: 10.1016/j.scitotenv.2017.05.193. Epub 2017 May 26.

Authors

Sara Pedro¹, Conor Boba², Rune Dietz³, Christian Sonne³, Aqqalu Rosing-Asvid⁴, Martin Hansen⁵, Anthony Provatas⁶, Melissa A McKinney²

Affiliations

¹ Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT 06269, USA. Electronic address: sara.pedro@uconn.edu.
² Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT 06269, USA.
³ Department of Bioscience, Arctic Research Centre, Aarhus University, Roskilde DK-4000, Denmark.
⁴ Greenland Institute of Natural Resources, Nuuk DK-3900, Greenland.
⁵ Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720, USA; Department of Integrative Biology, University of California, Berkeley, CA 94720, USA.
⁶ Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT 06269, USA.

PMID: 28554115
DOI: 10.1016/j.scitotenv.2017.05.193

Abstract

Sightings of killer whales (Orcinus orca) in Greenland have increased in recent years, coincident with sea ice loss. These killer whales are likely from fish-feeding North Atlantic populations, but may have access to marine mammal prey in Greenlandic waters, which could lead to increased exposures to biomagnifying contaminants. Most studies on polychlorinated biphenyl (PCB) and organochlorine (OC) contaminants in killer whales 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 ΣPCB, Σchlordanes (ΣCHL), and Σdichlorodiphenyltrichloroethane (ΣDDT) were found in the southeast Greenland and Denmark individuals (means of ~40 to 70mgkg^-1 lipid weight). These concentrations were higher than in the Faroe Island individuals (means of ~2 to 5mgkg^-1 lipid weight) and above those previously reported for other fish-feeding killer whales in the North Atlantic, likely in part due to additional feeding on marine mammals. On a wet weight basis, concentrations of all contaminants were significantly lower in the outermost blubber layer (0.15-0.65cm) compared to all other layers (p<0.01), except for Σhexachlorocyclohexanes. However, after lipid correction, no variation was found for ΣCHL and Σchlorobenzene concentrations, while the outermost layer(s) still showed significantly lower ΣPCB, ΣDDT, Σmirex, Σendosulfan, and dieldrin concentrations than one or more of the inner layers. Yet, the magnitude of these differences was 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.

Keywords: Biopsy; Orca; Persistent organic contaminants; Stratification; Transplacental transfer.

MeSH terms

Adipose Tissue / chemistry*
Animals
Arctic Regions
Denmark
Environmental Monitoring
Greenland
Pesticides / analysis*
Polychlorinated Biphenyls / analysis*
Water Pollutants, Chemical / analysis*
Whale, Killer*

Substances

Pesticides
Water Pollutants, Chemical
Polychlorinated Biphenyls