Heavy metal pollution of ecosystem within the middle course of the Jihlava River

Concentrations of Hg, Pb, Cd, Cr, Ni, Cu and Zn were monitored in fish muscle, water, bottom sediments and zoobenthos in the Jihlava River, Czech Republic, in May and July of 2007. Two localities were chosen, Vladislav and Hrubsice, upstream and downstream of the Dalesice and Mohelno dam reservoirs, respectively. Samples of fish muscle were taken from Leuciscus cephalus, Barbus barbus and Salmo trutta m. fario. The samples were analysed with the apparatuses AMA 254, AA-300 and SPECTR AA-30. Hg concentrations in water were above the maximum residue limit (0.1 microg/L) in both sites (Hrubsice: 0.99 microg/L, Vladislav: 2 microg/L). The bottom sediments in Vladislav were contaminated especially by Pb (120.21 mg/kg) and Cr (164.90 mg/kg), whereas in Hrubsice by Ni (90.66 mg/kg). High concentrations of Pb (25.84 mg/kg) in Vladislav, of Ni (240.90 mg/kg) and Cr (140.5 mg/kg) in Hrubsice were found in zoobenthos. Significantly higher concentrations of Hg were found in barbel and chub from Vladislav (0.155 mg/kg and 0.163 mg/kg, resp.) than from Hrubsice (0.073 mg/kg and 0.095 mg/kg, resp.), and of Cd in chub (Vladislav: 0.062 mg/kg, Hrubsice: 0.006 mg/kg), whereas Ni level in barbel was significantly higher in Hrubsice (0.175 mg/kg) than in Vladislav (0.050 mg/kg). The last significant difference was found in Pb concentrations as fish from Hrubsice were more contaminated (0.155 mg/kg in barbel and 0.182 mg/kg in chub) than the same species from Vladislav (0.050 mg/kg and 0.064 mg/kg, resp.). In both sites, Hg was the most limiting factor for fish consumption.