Effects of combined exposure to metal mixtures and natural stressors on aquatic invertebrates: relating changes in metal uptake to altered behavior and ecological effects.

Metals are posing a worldwide threat to aquatic ecosystems. In the natural environment trace metals most often occur in different mixtures, in which metals can strongly interfere with each other, producing antagonistic, synergistic or additional toxic effects. Besides the presence of pollutants also natural stressors such as fluctuating temperature, food shortages and predators are present that might negatively affect organisms and alter metal bioavailability. Current environmental quality standards (EQS) however are mainly based on laboratory tests under strictly controlled conditions in which test organisms are exposed to single compounds for alimited period of time. Moreover, in the setting of environmental standards more sensitive endpoints such as behavior have never been used. As a result the current EQS for metals might result in under- or in overprotecting the environment.The aim of this study is to investigate the combined effects of metal mixtures and the natural stressors temperature, food and predation pressure on the behavior of three aquatic invertebrates. This behavior will be compared to classical endpoints, e.g.reproduction and growth. In addition effects on a whole aquatic community will be assessed in artificial streams and ponds. Combining metal mixtures with predator stress and assessing the effects of this combination on different levels of biologicalorganization is highly innovative and will contribute to the development of ecological relevant EQS.

Keywords:METAL POLLUTION, INVERTEBRATES

Disciplines:Geology, Ecology, Aquatic sciences, challenges and pollution, Environmental science and management, Other environmental sciences