Residues of Pollutants in Siluriformes from Various Locations of the Czech Republic

Abstract

were investigated for residues of pollutants in wels (Silurus glanis) from 6 large ponds (Bezdrev, Spolsky, Kaclehy, Vrko<:, NovoveskY, Bezruc), from Labe river and from the OrUk reservoir and in brown bullhead (lctalurus nebulosus) from the river Labe. Thirty and 10 individuals of wels were investigated from ponds and the Orlik reservoir, respectively, and 2 individuals from the river Labe. Thirty five individuals of bullhead were investigated from various localities of the Labe. Among pollutants, metals (Hg, Pb, Cd, Cu, Zn, Cr, AI), PCBs as amount of technical mixtures used in .the Czech Republic (Delor 103 and Delor 106) and as 7 indicator congeners (K28, K52, KIOI, K118, K153, K138, KI80), DDT and its metabolities, HCB, HCH isomers, triazines (atrazine, simazine, prometryne, desmetryne, terbutryne) were assessed. The values of individual pollutants found in tissues of wels from ponds were very low and corresponded to hygienic limits in all cases. On the other hand, much higher values of pollutant residues (Hg and PCB) were found in wels from the OrUk reservoir, and they exceeded the hygienic limit in some cases (PCB). Values of pollutant residues found in bullhead fished from various localities of the Labe were also increased. Above all, PCB and mercury values exceeded valid hygienic limit of the Czech Republic in some cases.