PARENT SESSION
5C Ecological relevance of endocrine disruption
9:00 AM to 7:00 PM, Tuesday, 08 May 2001
Session Chair:

(T/FF211) Effects of 17 -ethinylestradiol on the zooplankton of freshwater microcosms.

Jaser, Wolfgang¹, Severin, Gabriele¹, Pfister, Gerd¹, Kettrup, Antonius¹, Schramm, Karl-Werner¹, ¹

ABSTRACT- An important aspect in ecotoxicological research is the meaning of endocrine substances for the aquatic environment. Based on former reference experiments with nonylphenol and ethinylestradiol (Severin 2000) this study investigates possible effects of 17 -ethinylestradiol on the zooplankton biocenosis of aquatic model ecosystems. The microcosms were filled with sediment (10 cm) and water (230 L) from an oligotrophic area of Lake Ammersee (Bavaria, Germany). After a pre-exposure phase of seven weeks, six microcosms were treated with 17 -ethinylestradiol in six different concentrations (max. 725 ng/L) by using a controlled released system for six weeks to simulate contamination conditions close to reality. After the application phase, the microcosms were observed for another twelve weeks to investigate the recovery of the zooplankton community. Six microcosms served as controls and remained untreated. In weekly intervals the water temperature, oxygen saturation, pH, conductivity, NO3-N, PO4-P and NH4-N were measured and plankton samples were taken. In addition to that, the content of chlorophyll a was determined. Considering these data as well as possible interactions in the food web, an interpretation of direct and indirect effects of the substance on the population dynamics of the zooplankton in the microcosms is tried. Severin G.F. (2000) Effekte hormonell wirksamer Substanzen auf das Zooplankton aquatischer Modelloekosysteme. Dissertation, Technische Universitaet Muenchen.

Key words: microcosm, zooplankton, endocrine disruptor, ethinylestradiol