Heavy metals in the nase, Chondrostoma nasus (L. 1758), and its intestinal parasite Caryophyllaeus laticeps (Pallas 1781) from Austrian rivers: bioindicative aspects.

Tissue samples from 121 adult specimens of the predominantly herbivorous fish species nase, Chondrostoma nasus (L. 1758), from five river sites in Austria were analyzed for their metal content. Sediments and water samples of the sites show different levels of metal load, with only one site considered being polluted with metals. The concentrations of cadmium, copper, lead, and zinc in the tissue of the gills, muscle, intestine, and liver of the fish were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). As in one of the unpolluted and the polluted river site, a well-established population of the tapeworm Caryophyllaeus laticeps (Pallas, 1781) occurred in the intestine of the fish; pooled samples of this worm were analysed as well. Both the nase and C. laticeps show bioindicative ability for metal pollution in rivers. The results allow a more differentiated characterization of the rivers than the sediment analyses. Cadmium is found mainly in the liver, with maximum concentrations of 1.57 microg/g dry weight from unpolluted sites and 5.58 microg/g from the polluted site. The highest concentrations of copper are also found in the liver, with values between 25 and 333 microg/g. A significantly elevated concentration of Cu in the intestine from an "unpolluted" site (mean: 24.06 microg/g) indicates an acute pollution in this area at the time of sampling. Lead was found mainly in the intestine and liver in concentrations between 0.09 and 4.05 microg/g and 0.26 and 1.94 microg/g, respectively. In the samples from the polluted site, it also could be detected in the gills (mean: 1.38 microg/g). The parasite C. laticeps shows different capacities for metal accumulation: Although the concentrations of Cu were significantly lower compared to the values of the fish liver, cadmium was detected in concentrations up to 5.1 times higher. Lead and zinc concentrations were found to be up to 9.7 and 3.0 times higher in the tapeworm compared to the fish liver, respectively.