Assessment of selected heavy metals pollution in water, sediments and fish in the basin Dyje, Czech Republic.

OBJECTIVES: This study presents the concentrations of heavy metals (Cr, Cd, Hg, Zn and Pb) in the water, sediment, and muscle of two fish species from the middle and lower reaches of the Dyje river basin (Dyje, Jihlava, Svratka, Svitava and Trkmanka rivers), in the Czech Rebublic.

METHODS: Samples of water, sediment (Tab. 1.) and fish muscle were obtained during the seasons of 2012-2013. As the reference species were chosen chub (Squalius cephalus) and roach (Rutilus rutilus) due to their occurrence in all of the evaluated fishing grounds.

RESULTS: The potential ecological risk analysis of heavy metal concentrations in the sediments indicated that nine sites in the middle and lower reaches posed moderate or considerable ecological risk. The health risk analysis of individual heavy metals in fish muscle indicated safe levels for the general population, but there was a possible risk in terms of the total target hazard quotients. The contents of the analysed metals in fish muscles were low at seven sites and did not exceed the values of limits admissible in the Czech Republic.

CONCLUSIONS: The increased values of heavy metals in the fish muscle from the Svratka and Svitava rivers may be mainly derived from metal processing, electroplating industries, industrial wastewater and domestic sewage.