All three jewelweeds species (Impatiens. L.)contain series of secondary metabolites from category of phenolic substances, e.g. naphthoquinones. This substances belong to allelochemicals, they can to affect germinability and growth of other plants. The extracts from jewelweeds (leaves, roots) and their fractions can to affect negatively germinability and growth of the chosen weed's seeds. Knowledges of allelopathic effects in jewelweeds species on other plants might be of important impact on ecological farming in the implementing of alternative herbicides.

There are many compounds that are used or produced by humans, e.g. pharmaceuticals and personal care products (PPCPs) which are used in large quantities around the world. These compounds end up in waste waters and enter sewage treatment plants (STPs). But not all of these compounds are removed during the treatment processes in STP and they enter the aquatic environment via sewage effluents. The thesis is focused especially on evaluation of presence and potential toxicological effects of PPCPs in aquatic environment. The risk assessment for a single compound is usually based on laboratory experiments. The first tested compound was verapamil, a pharmaceutical for lowering blood pressure and treatment of cardiac diseases. Two types of tests were carried out, an acute one with high concentration levels and a sub-chronic one with levels that included environmentally relevant concentration. After the exposure, common carp larvae and embryos showed malformation and edemas and the heart rate was decreased. According to 96hLC50, the verapamil could be classified as a harmful or toxic substance. The second tested substance was UV filter 2 phenylbenzimidazole-5-sulfonic acid which was found at relatively high concentrations in south Bohemian surface waters. In spite of very low bioconcentration of PBSA in fish, activities of 7-ethoxyresorufin-O-deethylase, 7-methoxyresorufin-O-deethylase and 7-penthoxyresorufin-O-deethylase in exposed rainbow trout were increased which indicate that activity of cytochromes P450 were affected even in environmentally relevant concentration. In a real aquatic system, fish are exposed to waters which contain not only a single pollutant but a mixture of them. A consequent experiment was carried out on rainbow trout caged in effluent for 13 days from STP in Gothenburg, the second biggest STP in Sweden. The concentration of selected antidepressants was measured in different fish tissues and plasma. Citalopram, sertraline and venlafaxine were found in fish brain and liver. As these antidepressants are used for the treatment of psychical disorders, behavior of fish could be affected. The limitations of these experiments, even with real water with a mixture of chemicals, are that fish are stressed in aquaria or cages and the exposure via the food chain is not included. Benthic organisms are an important part of fish diet. The impact of pollution on benthic organisms is often studied. However, there is limited knowledge about the bioaccumulation of pharmaceuticals in the benthos and consequently in fish. Therefore bioaccumulation in Hydropsyche and Erpobdella was studied. These organisms were collected in non-polluted and in effluent affected localities. Antibiotics azithromycin and clarithromycin, cardio-vascular drug verapamil, antifungal drug clotrimazole and antidepressants citalopram and sertraline were found in Hydropsyche. Cardio-vascular drug valsartan, antidepressant sertraline, anti-inflammatory drug diclofenac and antifungal drug clotrimazole were found in Erpobdella. Passive sampling is an integrative sampling method which allows the obtaining of time average concentration over period of few weeks. POCIS (Polar Organic Chemical Integrative Samplers) are used for sampling of polar compounds. It also can mimic bioconcentration. Based on the field experiments, the sampling rate for individual pharmaceuticals and illicit drugs was calculated. Twenty-one localities in the Czech Republic were sampled by POCIS and the water concentration of psychoactive drugs was estimated. Further research is necessary to make POCIS passive sampling a more precise tool for monitoring pharmaceutical and drug contents in aquatic environments.

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