Triad Assessment of the Impact of Chromium Contamination on Benthic Macroinvertebrates in the Chusovaya River (Urals, Russia)

Abstract.

The impact of chromium (Cr) contamination on the benthic macroinvertebrate community of the Chusovaya River in the Ural Mountains of Russia was assessed using a triad approach. The triad consisted of chemical analysis of the contamination in various environmental compartments, examination of the benthic macroinvertebrate community structure, and analysis of ecotoxicological effects on the caddisfly Hydropsyche pellucidula (Trichoptera). Chemical analyses of water, sediments, and detritus indicated that the main contaminant present was indeed Cr and that the level of the Cr contamination near the point source, a severely polluted dead tributary, was extremely high: Downstream Cr concentrations were about 450 times higher in water and 25 times higher in sediments compared with a clean reference site upstream. The contamination at the mouth of the tributary was even more severe: 800 times more Cr in water and 50 times more Cr in sediments. Benthic macroinvertebrate community structure was studied using artificial substrates colonized in situ. Lower species richness was observed at the downstream site compared with the upstream site. Larvae of H. pellucidula collected from the contaminated site on the river bioaccumulated large amounts of Cr and exhibited physical abnormalities. The incidence of tracheal gill damage was significantly higher than at a reference site on the nearby Reshotka River, as was the incidence of discoloration of the anal papillae of these animals. The application of a triad demonstrated that the observed extreme Cr contamination had an adverse effect on aquatic life in the Chusovaya River, both at the community level (reduced diversity) and at the level of individuals (sublethal effects on surviving individuals).