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(T/EH068) Differences in the population structure of gammarids: Are endocrine disruptors in effluents responsible? - Preliminary results. Ladewig, Vanessa1, Jungmann, Dirk1, Ludwichowski, Kai1, Metag, Nicole1, Preuß, Thomas2, Woitschella, Astrid2, Nagel, Roland1, 1 2 ABSTRACT- In recent years the endocrine disruptive activity of xenobiotics in ecosystems has gained a lot of attention, because of their potential to disturb population structure. The XEHOGAMM project was established to investigate the impact of endocrine disruptors on crustacean populations. For details see Jungmann et al.. As part of the project the population of Gammarus fossarum was monitored during 2000 in stream sites of the Koersch and the Lockwitzbach (Germany), respectively. At each stream, sampling upstream and downstream of the effluent of a sewage treatment plant was carried out. Samples of gammarids were collected every four weeks. Appropriate sampling techniques and in case of very large samples splitting procedures were developed. Especially at the site downstream of the effluent the abundance of gammarids in the Koersch was higher than in the Lockwitzbach. The dynamics of the different populations were compared. The size, sex ratio and percentage of juveniles, males, females and ovigerous females were determined in the different populations. These endpoints were chosen as they are population relevant variables and differences could lead to consequences for the population dynamics. The stream water and the effluents were analysed by GC/MSD for potential endocrine disruptors. Differences of the population dynamics were discussed regarding physico-chemical water variables and the concentrations of xenobiotics. The project is funded by the Umweltbundesamt, FKZ 29965221/05. Key words: endocrine disruption, Gammarus fossarum, population ecology, sewage treatment plant effluents |
