Observation of the quality of Danube water in the Belgrade region based on benthic animals during periods of high and low water conditions in 2002

The present paper states conclusions about the quality of Danube water in the Belgrade Region based on analyses of the invertebrate community. The investigation was performed during periods of high (May, 2002) and low (October, 2002) water conditions. Meio- and macrozoobenthos were observed. Qualitative, quantitative, and saprobiological analyses were performed. The sampling area covered five stations along 66 km of the river. The community was represented by 26 species. Aquatic worms were the principal component of the benthos with respect to both species richness (six species) and abundance (58.39-99.47 % of the total community). Gastropods were also diverse (six species). Snails were found to be subdominant as far as participation in the total community density is concerned. Structure of the benthic community and the saprobity index (S= 2.78-3.43) indicated the presence of organic pollution. No notable differences of estimated environmental quality were observed between a station upstream from Belgrade and one situated below the exit from the broader territory of Belgrade. Since Belgrade is recognized as one of the main contaminants in regard to biodegradable pollutants in the Middle Danube, this finding points to an impressive self-purifying ability of this huge river