Bioaccumulation of Organochlorine Contaminants in Bowhead Whales (Balaena mysticetus) from Barrow, Alaska

Abstract

Bowhead whale (Balaena mysticetus) blubber (n = 72) and liver (n = 23) samples were collected during seven consecutive subsistence harvests (1997–2000) at Barrow, Alaska, to investigate the bioaccumulation of organochlorine contaminants (OCs) by this long-lived mysticete. The rank order of OC group concentrations (geometric mean, wet weight) in bowhead blubber samples were toxaphene (TOX; 455 ng/g) > polychlorinated biphenyls (ΣPCBs; 410 ng/g) > dichlorodiphenyltrichloroethane-related compounds (ΣDDT; 331 ng/g) ≥ hexachlorocyclohexane isomers (ΣHCHs; 203 ng/g) ≥ chlordanes and related isomers (ΣCHLOR; 183 ng/g) > chlorobenzenes (ΣCIBz; 106 ng/g). In liver, ΣHCH (9.5 ng/g; wet weight) was the most abundant ΣOC group, followed by ΣPCBs (9.1 ng/g) ≥ TOX (8.8 ng/g) > ΣCHLOR (5.5 ng/g) > ΣCIBz (4.2 ng/g) ≥ ΣDDT (3.7 ng/g). The dominant analyte in blubber and liver was p,p′-DDE and α-HCH, respectively. Total TOX, ΣPCBs, ΣDDT, and ΣCHLOR concentrations in blubber generally increased with age of male whales (as interpreted by body length), but this relationship was not significant for adult female whales. Biomagnification factor (BMF) values (0.1–45.5) for OCs from zooplankton (Calanus sp.) to bowhead whale were consistent with findings for other mysticetes. Tissue-specific differences in OC patterns in blubber and liver may be attributed to variation of tissue composition and the relatively low capacity of this species to biotransform various OCs. Principal component analysis of contaminants levels in bowhead blubber samples suggest that proportions of OCs, such as β-HCH, fluctuate with seasonal migration of this species between the Bering, Chukchi, and Beaufort Seas.