sewage sludge, toxicity tests, Eisenia foetida, Sinapis alba

The goal of the submitted work was to determine the applicability of the combination of two contact bioassays - the acute toxicity test with Eisenia foetida and Phytotoxkit micro-bioassay with Sinapis alba - for assessment of sewage sludge ecotoxicity. The samples were analyzed chemically for the indicators PCBs, PAHs, heavy metals, OCP and EOX. The permissible limits were exceeded in the case of PAHs, Hg and Pb. The bioassays results showed that at a sludge concentration of over 50 % (seeds) and 60 % (earthworms), a 100 % mortality or growth inhibition was observed. Concurrent application of the two contact tests showed an acute toxicity on both invertebrates and plants. The evaluated sewage sludge can be considered to be potentially ecotoxic.