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(18-11) Oestrogenic endocrine disruption in flounder from UK estuaries: Preliminary temporal trend data. Kirby, Mark*,1, Allen, Yvonne1, Dyer, Robert1, Tolhurst, Laura1, Matthiessen, Peter1, Katsiadaki, Ioanna2, Scott, Alexander2, 1 CEFAS Burnham Laboratory, Burnham-on-Crouch, Essex2 CEFAS Weymouth Laboratory, Weymouth, Dorset ABSTRACT- Plasma vitellogenin concentrations (VTG) in the blood of male flounder is an established biomarker of estuarine oestrogenic endocrine disruption. Surveys in 1996/97 established the spatial extent and severity of oestrogenic contamination in UK estuaries. Male flounder showed mean plasma VTG levels routinely above 105 ng/ml and peaking at 107 ng/ml at some locations. These surveys established the Mersey, Tees and Tyne estuaries as 'hotspots' with respect to plasma VTG levels. Under the UK Endocrine Disruption in the Marine Environment (EDMAR) programme measurements of plasma VTG in flounder have continued at a number of sites to provide time series information. Four surveys (September 1999, March 2000, November 2000 and February 2001) were conducted and the data compared to the results from earlier surveys. The data show some interesting trends and, although it is too early to draw firm conclusions, suggest that male plasma VTG levels are falling in some areas. Mersey fish have shown a two orders of magnitude reduction (from 107 to 105 ng/ml) between 1996 and 2000 although the latest dataset suggest a small rise. Most notable are the reductions in the Tyne where values at previously high sites of Hebburn and Howdon have been near baseline since late 2000. Conversely, samples from St Anthonys (SA) on the Tyne and Dabholm Gut (DG) on the Tees have shown little evidence of a reduction during the study period. While at SA the VTG levels have fluctuated those at DG have stayed relatively constant since 1997 with means remaining above 106 ng/ml. Continued monitoring will be required to establish clear trends. However, the results suggest that oestrogenic contamination in some areas may be reducing while for others environmental effects remain seemingly unchanged. Key words: endocrine disruption, flounder, vitellogenin, temporal trend |
