Nowadays, nanoscale zerovalent iron (nZVI) is a nanomaterial commonly used in remediation practice. Although worldwide applications of nZVI have shown its effectiveness in degradation and immobilization of a wide range of organic and inorganic pollutants, potential negative effects of nZVI on exposed organisms have not been sufficiently explored. To avoid possible environmental risks, understanding of the mechanism of nZVI toxicity and its overall effects on microbial populations indigenous to remediation sites is needed. The presented thesis summarizes current knowledge of nZVI toxicity, and, moreover, deals with the development and application of a new test for in vitro evaluation of acute toxicity caused by newly developed nZVI-based materials. Additionally, in this thesis, the risk associated with changes in the toxicity of the aforementioned materials during the aging process was examined. In the last part, the effect of several nZVI-based materials on microbial communities of a real contaminated soil was monitored and evaluated using artificial microcosms. In addition, in this part, the potential of nZVI and its derived materials in combination with a biostimulation step during nanobioremediation is outlined.

The aim of this diploma thesis was to determine the dehydrogenase activity of matrix samples that can enter the environment and the use of ecotoxicological tests to assess the quality of the affected soil. The effects of sludge, biochar samples, two landfill samples and a sediment sample were monitored. Ecotoxicology included tests on decomposers - tests of avoidance behavior (Eisenia fetida and Folsomia candida), acute, chronic and reproductive toxicity tests (Eisenia fetida) and Lactuca sativa root growth inhibition tests. The results indicate that dehydrogenase activity assays serve as a suitable complement to ecotoxicological tests. They provide valuable additional information on soil quality and sample effect after application to soil. The sediment sample had the least favorable effect on the activity of the enzyme and the vitality of the organisms, both in the determination of dehydrogenase activity and in ecotoxicological tests. Furthermore, it was found that biochar as a product of sewage sludge treatment is less toxic to organisms than the original sludge.

This work sums up results of tests of ecotoxicity that were made on different kind of industrial waste materials like classical ash, fluid and fly ash, slags as well as anorganic composites containing waste materials. Composites might be used for building materials in the future. Ecotoxicological tests were used for evaluation of ecotoxicity, represented by 4 trophic levels, with several bioindicators evaluated at different exposure time periods. The battery of classical tests includes a growth inhibition test of the freshwater alga Raphidocellis subcapitata, an immobilization test of the cladoceran Daphnia magna and freshwater fish Poecilia reticulata and a test of inhibitive effects on the root growth of white mustards Sinapis alba. Tests with enchytraeidae, collembolan and lettuce were chosen from group of contact tests. It was realized confrontation between classical test with seeds of mustard and contact tests with seeds of lettuce. Results of ecotoxicity tests were determination of percentage of mortality, immobilization, stimulation or inhibition of growth for testing organisms. It was made comparison of results individual ecotixicity tests. Results of classical aquatic tests were compared with contact tests realized in artificial ground.