Determination of total mercury and mercury species in fish and aquatic ecosystems of Moravian rivers

Abstract

Contents of total mercury and mercury species (methylmercury – MeHg, inorganic mercury – Hg²⁺) were determined in four Moravian rivers – Jihlava, Becva, Loucka and Dyje (Czech Republic). Five tissues (muscle, gills, liver, kidney and skin) of chub (Leuciscus cephalus), zoobenthos, sediments and water samples were analyzed. Time stability of samples was also tested. The highest levels of total mercury were determined in muscle tissues of all tested fish. Relative contents of MeHg in muscle tissues of fish ranged from 83.6% to 92.0% of the total mercury contents. The relative contents of MeHg in sediments and in zoobenthos samples correlate very closely (correlation coefficient –0.83). A considerably lower content of MeHg (1.3–11.4%) was found in river sediments compared with lakes. A comparison of observed sampling sites (Vladislav, Hrubsice) proved the adverse effect of industrial contamination on the water ecosystem ofJihlavaRiver and incomplete removal of mercury species in a sewage station