Publication Abstract

Relationships between polychlorinated biphenyls and health status in harbour porpoises (Phocoena phocoena) stranded in the United Kingdom

Relationships between polychlorinated biphenyls and health status in harbour porpoises (Phocoena phocoena) stranded in the United Kingdom.

P.D. Jepson, P.M. Bennett, R. Deaville, C.R. Allchin, J.R. Baker and R.J. Law

To investigate possible relationships between polychlorinated biphenyl (PCB) exposure and infectious disease mortality in harbour porpoises (Phocoena phocoena) in UK waters, summed blubber concentrations of 25 chlorobiphenyl congeners (Σ25CBs) in healthy harbour porpoises that died of acute physical trauma (mainly by-catch) (n=175) were compared with S25CBs in animals that died due to infectious disease (n=82). The infectious disease group had significantly greater Σ25CBs concentrations (mean = 27.6 mg kg^-1 lipid) than the physical trauma group (mean = 13.6 mg kg^-1 lipid)(p<0.001). This association occurred independently of other potentially confounding variables including age, sex, nutritional status, season, region and year found. Total blubber PCBs levels (as Aroclor 1254) were also calculated enabling direct comparison with a proposed threshold for adverse health effects (including immunosuppression) in marine mammals of 17mg/kg lipid weight total PCBs. Within a subset of porpoises with blubber total PCBs levels above the 17mg/kg (lipid wt) threshold (n=154), total PCBs levels remained significantly higher in the infectious disease group compared to the physical trauma group (p<0.001). However, this association was no longer significant in porpoises with total PCBs levels below the 17mg/kg threshold (n=103)(p>0.55). Collectively, these findings are suggestive of a causal relationship existing between PCB exposure and infectious disease mortality in harbour porpoises in UK waters, mediated by PCB-induced immunotoxicity at toxicologically relevant concentrations. The findings of this study provide a basis for future risk assessment analysis to quantify the ecotoxicological impact of PCB-related mortality in European harbour porpoise populations of known size and PCB exposure.

Reference:

P.D. Jepson, P.M. Bennett, R. Deaville, C.R. Allchin, J.R. Baker and R.J. Law (2004). Relationships between polychlorinated biphenyls and health status in harbour porpoises (Phocoena phocoena) stranded in the United Kingdom. Environmental Toxicology and Chemistry, 24:238-248

P.D. Jepson, P.M. Bennett, R. Deaville, C.R. Allchin*, J.R. Baker and R.J. Law*

Environmental Toxicology and Chemistry, 24(1): 238-248