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Title: Post mortem study of otters in England and Wales 1992-2003
Author: E.A. Chadwick
Author: Environment Agency
Document Type: Monograph
Annotation: Environment Agency Project ID:EAPRJOUT_1195, Representation ID: 376, Object ID: 2415
Post mortem examinations were carried out on 609 otters found dead in England and Wales between 1992 and 2003. Liver tissue was removed from a subsample of 350 animals and analysed for pollutants including organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs). This report summarises data from otters collected between 1992 and 2003. It follows Bradshaw and Slater (2002), which summarised data collected between 1992 and 2000. The most commonly occurring organochlorine pesticides measured in otter carcasses were the para para isomers of DDE and TDE (both derivatives of DDT - dichlorodiphenyltrichloroethane), and dieldrin. Dieldrin and pp’DDE were detected in 99 and 100 per cent of samples respectively in the latter three years of the study. Tissue concentrations of organochlorines were generally low, compared to data gathered in the 1960s and 70s. The dominant organochlorine in terms of concentration was pp’DDE, with a median concentration of 181 ~kg/kg wet weight. Nine polychlorinated biphenyl compounds were found in more than 95 per cent of samples since 2001. The dominant PCB was congener 153, with a median concentration of 72 ~kg/kg wet weight. Another pollutant, hexachlorobenzene (HCB), was found in 99.5 per cent of samples in the latter three years of the study. Levels of chemical pollutants showed some regional trends, with higher levels of PCBs in northern regions and higher levels of OCs in the Midlands. Levels of OCs, PCBs and HCB were higher in males than in females and highest in juveniles of both sexes. Also, levels of PCBs increased with increasing body size in males but not in females. These patterns probably reflect excretion of the pollutant burden in colostrum and milk by reproductive females.
Publisher: Environment Agency
Subject Keywords: RiversPollutantsOrganochlorine compoundsMortalityAquatic mammals
Geographic Keywords: EnglandWales
Taxonomic Keywords: Lutra lutra
Extent: 141
Total file downloads: 291

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