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(18-68) Estrogens and xeno-estrogens in the Dutch aquatic environment (LOES): II. Effects. Vethaak, A. Dick*,1, Gerritsen, Anton2, Lahr, Joost3, Rijs, Gerard2, Schrap, S. Marca2, van den Bergs, Jappie4, Versteegh, Ans5, Ruiter, Hans2, 1 Institute for Coastal and Marine Management, Kamperland, The Netherlands2 Institute for Inland Water Management and Waste Water Treatment, Lelystad, The Netherlands3 Aquasense, Amsterdam, The Netherlands4 Wetterskip Fryslan, Leeuwarden, The Netherlands5 National Institute of Public Health and the Environment, Bilthoven, The Netherlands ABSTRACT- The findings on the estrogenic effects in fish, carried out in frame work of a large-scale base-line study in The Netherlands (LOES-project), are presented. The freshwater bream (Abramis brama) and the estuarine flounder (Platichthys flesus) were sampled at 21 locations. Levels of the yolk protein vitellogenin (VTG) in blood plasma of male flounders were low on most sites. At a few sites, however, moderately elevated levels were found. One of these sites was an industrial harbour zone, the others were coastal/offshore spawning areas. In many of the 300 male bream captured, VTG levels were higher than those observed in flounder. The highest levels were observed in individuals collected from a small stream, close to the discharge of a relatively large municipal waste water treatment plant. This was also the only site where histologically visible hermaphroditism occurred; c. 37% of male bream showed ovotestis. Hermaphroditism was not observed in any of the 400 male flounders captured. Possible explanations for the observed spatial patterns and higher prevalence of effects in bream compared to flounder are presented and discussed in relation to concentrations of chemical contaminants (reported elsewhere at this meeting. The above-mentioned municipal effluent was chosen as a model effluent for further in vivo and in vitro testing. Using the ER-CALUX and transgenic zebra fish reporter gene assays and a zebrafish partial life cycle (PLC) test, estrogenic effects were clearly demonstrated, thus confirming the findings of the field survey. The results from Dutch waters are briefly compared to findings from similar studies conducted in other countries. Key words: estrogenic effects, monitoring, fish reproduction |
