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USING THE OTTER TO UNDERSTAND THE CHEMICAL CONTAMINATION OF OUR FRESHWATER ECOSYSTEMS O’Rourke, Emily1; Hailer, Frank1; Scholey, Graham2; Naura, Marc3 and Chadwick, Elizabeth A.1 1 Cardiff University Otter Project (CUOP), Biomedical Science Building, Museum Avenue, Cardiff 2 Environment Agency, Red Kite House, Howbery Park, Wallingford, Oxfordshire 3 The River Restoration Centre, Vincent Building, Cranfield University, Bedfordshire Fresh surface-water accounts for only 0.008% of all water on the planet, yet it sustains 5% of the worlds’ species and fulfils the majority of drinking water needs. Everyday two million tonnes of domestic, industrial and agricultural waste, equivalent to the mass of the entire human population, is discharged into the world’s waters. In the 1950s-70s otter populations in Britain and Western Europe suffered dramatic declines due to the bioaccumulation of PCBs and organochlorine pesticides (OCPs). This demonstrates the vulnerability of top predators to biomagnifying chemicals and therefore the need to ensure policy for manufacture, use and disposal of these chemicals is effective at protecting our freshwater ecosystems. The monitoring of water alone is not enough to understand the risks posed to wildlife; due to biomagnification, contaminant concentrations in biota may be at levels significant to animal health, while the abiotic samples from the same location have low concentrations. Therefore, it is only through biomonitoring that the actual exposure of organisms can be accurately determined and related to environmental levels. Since 1994 Cardiff University Otter Project has been collecting otters found dead for a wide range of research, the archive of liver samples provides a unique dataset for determining chemical concentrations in a top predator. I am investigating the current threat to otters caused by the banned, but persistent, PCBs and OCPs, plus the newer compounds PBDEs (fire retardants) and PFAS (surfactants), and using the otter as a sentinel to tell us how concentrations vary over time and geographically. |
