In our project we focus on the impact of water contamination on aquatic ecosystems and freshwater fauna. We have done an experiment on the influence of analgesics dissolved in water on aquatic invertebrates. In the experiment we prepared ten solutions of different concentrations of paracetamol and ibuprofen. Afterwards, we placed daphnia in the solutions. After one day, we were able to observe the results. On the basis of the experiment we determined the concentration of analgesics lethal to daphnia. We observed a curios phenomenon: the daphnia placed in the solutions containing ibuprofen practically dissolved. We made videos of the changes in heart rate in the daphnia depending on the concentration of the solution containing paracetamol. Shortly, we will be carrying out an experiment on the absorption of acidic substances and pollutants by soil and plants. The experiment has been made possible thanks to the cooperation with the National Institute of Public Health in Warsaw, which has kindly consented to our using its laboratory. We are also preparing an article on euthropication caused by fertilizers.