Environmental contaminants in tissues of a neonate St Lawrence Beluga Whale ( Delphinapterus leucas)

Abstract

Tissue samples of brain, kidney, liver, and blubber from a neonate St Lawrence beluga whale were analyzed for ortho and non- ortho polychlorinated (PCB) congeners, organochlorine (OC) compounds, polychlorinated dibenzo- p-dioxins and -dibenzofurans (PCDD/Fs), and total mercury. As γ-globulins, which indicate presence of colostrum, were not found in serum of the live neonate, it was unlikely that there had been lactational transfer of environmental contaminants to the neonate. No PCDFs were detected. Of the PCDD congeners, only OCDD was found in all tissues; ranging from 12 pg g −1 lipid in brain to 1138 pg g −1 in liver. Concentrations of ΣPCB (sum of 25 ortho and 4 non- ortho PCBs) and ΣDDT were lowest 3n brain (1.7 and 0.7 μg g −1 lipid, respectively), intermediate in kidney (4.1 and 2.3 μg g −1) and highest in liver (8.8 and 3.5 μg g −1) and blubber (17.6 and 2.2 μg g −1). PCB 126 was the predominant non- ortho congener. Toxic equivalent 2,3,7,8-TCDD concentrations (TEQs) (pg g −1 lipid) were: mono- ortho PCBs > non- ortho PCBs > PCDDs. Major individual OC compounds were DDE, HCB, oxychlordane and cis-nonachlor. Similar PCB and OC patterns were found for different tissues, with the exception of α-HCH in brain. Total mercury was detected in liver, kidney and brain at concentrations of 49–145 ng g −1 (wet weight). Concentrations of PCBs, OCs, and mercury in the neonate were lower than or in the lower range of those found in published data on female adult beluga whales of the St Lawrence, and this is probably due to absence of lactational transfer of contaminants in the neonate. Proportions of lower chlorinated PCBs, HCB, and HCH compounds were greater in the neonate than in these female whales, which may indicate preferential gestational transfer of these compounds.