Heavy Metal Contamination of the Louãka River Water Ecosystem

Vitek T., P. Spurn˘, J. Mare‰, A. Zikova: Heavy Metal Contamination of the Louaka River Water Ecosystem. Acta Vet Brno 2007, 76:149-154. Heavy metal contamination of the Louaka River water ecosystem was assessed in July 2005. We analyzed concentrations of T-Hg (total mercury), Cd, Pb, Cr, Cu, Zn, and Ni in water, sediments, zoobenthos, and in the brown trout (Salmo trutta m. fario) muscle and liver tissues (a total of 28 individuals) at four sampling sites. The highest Pb and Ni concentrations (4.634 - 12.050 and 0.689 - 24.980 mg·kg -1 ) were found in sediments. The zoobenthos was most contaminated by Zn and Cu (0.556 - 1.505 and 2.925 - 74.300 mg·kg-1). The heavy metal contamination of river water was highest in Ni and Cr (0.1 - 6.8 and 0.5 - 10.0 mg·l -1 ). Concentrations of heavy metals in the brown trout muscle were following (in mg·kg-1): Pb 0.108 ± 0.073 - 1.010 ± 0.506, Cd 0.003 ± 0.002 0.026 ± 0.022, Zn 3.956 ± 0.371 - 5.801 ± 1.718, Ni 0.058 ± 0.018 - 0.102 ± 0.046, Cr 0.028 ± 0.005 - 0.073 ± 0.039, Cu 0.329 ± 0.079 - 0.437 ± 0.064 and Hg 0.065 ± 0.008 - 0.106 ± 0.047. Statistical differences (P < 0.05) in the brown trout muscle were in Pb and Zn. Cd, Cu and Zn were markedly accumulated in the brown trout liver (concentrations 0.107 ± 0.066 - 0.223 ± 0.078, 59.973 ± 38.951 - 145.800 ± 48.286 and 30.671 ± 3.574 - 34.274 ± 7.226 mg·kg -1 ). Humans of 60 kg body mass may consume 1.5 kg of brown trout muscle from the Louaka River weekly without any risk. Adverse influence of the Uniglas distillery on the Louaka River environment contamination by heavy metals was not confirmed.