PARENT SESSION
1D Bioassays for specific hazards (estrogenic effects, genotoxicity, neurotoxicity, ...)
9:00 AM to 7:00 PM, Tuesday, 08 May 2001

(T/EH040) Assessment of estrogenic activity in sewage treatment plant effluents using various in vitro systems. Comparative analysis and inhibition problems.

Rutishauser, Barbara¹, Pesonen, Maija¹, Ackermann, Gabriele¹, Zehnder, Alexander¹, Eggen, Rik¹, ¹

ABSTRACT- A recombinant yeast screen (Routledge E.J. and Sumpter J.P. Environ. Toxicol. Chem. 15 (3): 241-248, 1996) was used to assess estrogenic activity of three sewage treatment plant effluents (STPE) in Switzerland as part of the EU project COMPREHEND (Community Programme of Research on Environmental Hormones and Endocrine Disrupters). The effluents showed estrogenic activity ranging from 0.6 to 45ng/L estradiol equivalents. Activity in this range is also found in other European countries involved in the project. The results obtained with the yeast system were comparable to data obtained with rainbow trout based in vitro screening systems, i.e. the induction of zona radiata protein in fish hepatocytes (Pesonen M. et al., in preparation) and reporter gene activity in transfected rainbow trout gonad cells (Ackermann G.E. et al., in preparation). These findings indicate that the yeast system is indeed a useful tool for first screening purposes. Various samples showed an inhibitory effect in the yeast screen. This was observed as a) an increase in the amount of estradiol equivalents upon dilution of the STPE sample, and b) a reduced response to the standard compound -estradiol in the presence of certain STPE samples. Since the inhibition is of importance in a risk assessment programme, it is currently further investigated. Data and possible explanations for this inhibition phenomena will be presented.

Key words: estrogenic activity, sewage treatment plant effluents, recombinant yeast system, inhibition