Abstract

Soil microorganisms play a key role in transformation and decomposition of organic matter in soil and are also significant part of food, nutrient and energy cycles in terrestrial ecosystems. Persistent organic pollutants (POPs) represent toxic and bioaccumulative chemicals that are wide spread and have a potential to remain in the environment unchanged for many years. Soil is in most cases a target dump of these substances and also the main source of secondary contamination. Therefore the risk potential for the non-target soil organisms (microorganisms) and main microbial processes should be assessed. This work summarized available information about toxic effects of POPs on soil microbial community as well as the application of microorganisms for POPs biodegradation. Practical part was focused on testing the effects of the persistent organochlorine pesticide, toxaphene, and industrial products, short-chain chlorinated paraffins, on soil microorganisms in laboratory incubation tests. Analyzed parameters were microbial biomass content, soil respiration activity and nitrogen mineralization potential. Results showed that toxaphene was not toxic even at concentration 1000 ppm. The toxicity of the selected chlorinated paraffins on soil microorganisms was also very low. In general, substrate-induced respiration and ammnonification were the most sensitive parameters. Due to low levels of tested chemicals in soil and high effective concentrations, the risk potential for soil microorganisms could be negligible. …víceméně