Ecotoxicological Assessment of Sediment Leachates of Small Watercourses in the Brno City Suburban Area (South Moravia, Czech Republic)

Abstract

Sediments of two small watercourses Leskava and Troubsky Brook in the Brno city suburban area were examined for their ecotoxicity. Using a standard procedure, extracts of the sediments were prepared for diagnostic tests. These extracts were tested for acute toxicity to fresh-water organisms. The ecotoxicological tests were performed on the fresh-water algaPseudokirchneriella subcapitata, the vascular water plantLemna minor, on a representative of invertebrates – the water fleaDaphnia magnaand on theXenopus laevisfrog embryo and luminiscentVibrio fischeribacteria. Possible toxic effects were evaluated using the test determining the inhibition of the growth of white mustard rootSinapis alba. Results of ecotoxicological assessment of sediment leachates showed that their quality varied significantly during the year. Differences were found between results of sediment evaluations from different collection profiles, which may indicate effects of point source pollution. Of the ecotoxicological tests used, the most sensitive organisms included the green algaePseudokirchneriella subcapitata, bioluminiscent bacteriaVibrio fischeriand the African clawed frogXenopus laevis. The highest concentrations of arsenic were found by chemical analysis in both spring and autumn sediment leachate samples collected at Site L1 (Leskava). The highest organic pollutant concentrations were found in autumn sediment leachate samples from Site L1. In total PAH sums, phenanthrene was the dominant pollutant at all the sites investigated.