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ABSTRACT. The aim of this research was to investigate the type of relationships between the concentrations of heavy metals in bottom sediments and in selected roach, Rutilus rutilus (L.), organs. The material studied included kidney, liver, gill, and muscle tissues of roach caught in selected areas of the Oder River. The contents of Cd, Pb, Zn, and Cu were analyzed in fish organs. The content of heavy metals in roach organs differed depending on the organ or, in some cases, on the feeding site. The concentration of heavy metals in bottom sediments also depended on the site of their collection. Positive mutual correlations between concentrations of selected metals in fish and bottom sediments were found. The contamination of bottom sediments in the lower reaches of the Oder River with Cd, Pb, Zn, and Cu was diverse and depended on the sampling area. The accumulation of metals in the organs of the studied fish varied and was positively correlated with the concentration of metals in sediments.

Background. Chemical substances, including heavy metals, introduced into aquatic ecosystem can disturb the homeostasis of a habitat. The aim of this study was to assess the effects of cadmium compounds on common carp, Cyprinus carpio L. and to follow the toxicodynamics of cadmium elimination from intoxicated fish once they were transferred to a clean ambience. Material and methods. Common carp were given a single intraperitoneal injection of a sub-lethal cadmium dose (10 µg • kg-1 body weight) to assess their detoxification potential following transfer to uncontaminated habitat. The 60-day experiment was divided into 8 stages during which various organs and tissues of the fish (liver, kidneys, skin, gills, alimentary tract, and muscles) were examined and subjected to assays for cadmium contents at pre-set times. Cadmium was determined with flameless graphite furnace atomic absorption spectrometry (GF-AAS) in a ZL 4110 Perkin Elmer spectrometer after wet digestion in concentrated HNO 3 in CEM MDS 2000 microwave oven. Results. The fish intoxicated with Cd were sluggish, their responses to light and sound were much slower than those of the control fish. The cadmium level was observed to change with time: after initial cadmium accumulation in the tissues, the xenobiotic was eliminated. The experiment explains changes in the intoxicated carp system during the process of detoxification. The highest biological half-life (t 1/2) of cadmium was recorded in the muscles (37 days), the lowest being typical of the liver (3.4 days). Conclusion. During detoxification, cadmium was observed to be redistributed among the organs. Metal elimination rate was depended on organ and varied from 0.001 to 0.006 µg • day-1. A long-term effect of sub-lethal intoxication was an about 10-percentage-point reduction of the fish body weight.

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ABSTRACT. The experiment was carried out to determine the potential of heavy metals (Cd, Pb, Cu and Zn) passing from bottom sediments to fish and to identify the correlations between concentrations of these metals in bottom sediments and those in fish. The study material consisted of guppies Poecilia reticulata Peters and bottom sediments with known concentrations of the determined metals in particular fractions. As result of the 60-day exposure of the fish to environments with bottom sediments containing various heavy metals loads, an increasing trend was observable for cadmium and lead concentrations in guppies. Comparative analysis showed that the degree of bottom sediment heavy metal contamination influenced concentrations of these in the guppies. It was found that even small changes in environmental conditions affected the release of metals from bottom sediments, which resulted in notable differences in the concentrations of the examined metals in the fish.