The extent of oestrogenic contamination in the UK estuarine and marine environments - further surveys of flounder

In 1996, The Centre for Environment, Fisheries and Aquaculture Science (CEF AS) initiated a project to establish whether oestrogenic materials are pres ent in UK estuarine and marine waters at biologically significant concentra tions, and to investigate some of the possible effects which these may have in flounder (Platichthys flesus). Early results are published elsewhere; t his paper describes the results of a second wider survey of vitellogenin an d reproductive abnormalities in UK flounder. Vitellogenin levels in male bl ood plasma in the period from spring to winter 1997 were found to be signif icantly elevated (in comparison with a clean reference site on the Alde est uary) in at least one sample from most of the 11 estuaries investigated. Th e exceptions were the Tamar and the Dee where all fish appeared entirely no rmal. In broad terms, the degree of oestrogenic contamination as measured b y male vitellogenesis in the various estuaries was ranked in the following descending order: Tees > Mersey > Tyne > Wear = Humber = Clyde = Southampto n Water = Thames > Dee = Tamar. VTG concentrations in Tees, Mersey and Tyne male fish were extremely high (> 100000 ng/ml), and often exceeded those n ormally found in sexually mature females. At most locations, ovotestis cond itions in male flounder were entirely absent but 9% of male Mersey fish and 7% of male Tyne fish contained ovotestis. In a few cases, eggs were fully developed with yolk granules. Most testes did not show gross morphological abnormalities related to oestrogenic exposure, although one testis from a M ersey fish appeared to be almost entirely composed of eggs. Abnormal sex ra tios were not seen in any estuary. The paper concludes by outlining a new r esearch programme which will be addressing the biological significance of t hese observations. Crown Copyright (C) 1999 Published by Elsevier Science B .V. All rights reserved.