Aquatic organisms on the pill - effects on different organizational levels

Abstract: Communities are composed of organisms that interact with each other and with the non-biological environment. There are also anthropogenic pollutants in the environment that also interact with the organisms. Estrogenic endocrine disrupting compounds, for example 17?-ethinylestradiol (EE2, the active compound in contraceptive pills), released into surface waters can have negative effects on the organisms living there. Fish are sensitive to estrogenic EDCs and exposed fish can be less fertile and have inhibited reproductive behaviors that may lead to reduced population sizes while the majority of invertebrates are not sensitive, with the exception of mollusks. With the difference in sensitivity is likely that there may be consequences for aquatic communities, such as changes in the structure and dynamics. We have studied the effects of EE2 on different organizational levels in the aquatic community and with the emphasis on end-points not connected to reproduction. We have shown that fish exposed to EE2 had inhibited somatic growth, increased size of liver, decreased size of gonads and also reduced foraging performance that indirectly affected prey communities by releasing them from predation. We have also shown that EE2 can inhibit or enhance somatic growth rates in gastropods depending on specie, but population growth rates was not affected, and that EE2 pollution history in gastropods may also influence the effects of novel stressors. Furthermore, we showed that EE2 can interfere with detoxification and apoptosis in copepods (crustacea) and this can make them more sensitive to novel stressors and affect molting and population demography. The effects of EE2 we have observed on the organisms in our studies, together with the known negative effect on fish reproduction, may have consequences for community structures and ecosystem functioning in surface waters that receive EE2 or other estrogenic EDCs and.