The aim of the present work was to compare the distribution of selected metals in tissues of several fish species caught in the Věstonice reservoir. The hygienic quality of fish meat was assessed with respect to the mercury concentration. A total of 35 fish of the following species were caught: carp (Cyprinus carpio), bream (Abramis brama), asp (Aspius aspius), pikeperch (Sander lucioperca) and pike (Esox lucius). Samples of muscle, liver (hepatopancreas), kidney, gonads and gills were analyzed. Hg, Pb, Cd, Cu, Zn and Cr concentrations in fish tissues were determined by the AAS. The results showed that different metals differ in their affinity to different fish tissues (e.g. Cu -liver, Cd -kidney). Mercury concentrations along the food chain increase, i.e. higher mercury concentrations are found in predatory fish. Contrary to mercury, cadmium and lead concentrations do not show any increases along the fish part of food chain in surface water ecosystems. In predatory fish, lower concentrations of these metals were found than in nonpredatory fish species. Differences in concentrations between ovaria and testes were found only in Cu and Zn. To evaluate possible health risks of mercury concentrations for consumers, the risk index was calculated and maximum admissible amounts of muscle meat for consumption were determined. The results confirmed good hygienic quality of market-ready fish from the Věstonice reservoir. Predatory fish, non-predatory fish, heavy metals, AAS, risk indexThe rising living standards of human population take their toll in increasing loads to the environment with various contaminating substances that occur naturally at very low concentrations, or do not naturally occur at all. Besides metal manufacturing and processing, the sources of environmental metal contamination include industrial waste products, the burning of fossil fuels, and the use of metals by consumers. The increase in metal concentrations in the environment is further enhanced by their poor degradability resulting in metal accumulation in the soil, water sediments and the food chain (Svobodová et al. 1987).As the final link of the food chain in the aquatic environment, fish are an important indicator of contamination by a number of substances, including metals (Svobodová et al. 1996). Moreover, toxic metal concentrations in fish are monitored also in terms of food safety (Svobodová et al. 2004). First and foremost, the most closely monitored potentially toxic metals include mercury followed by cadmium and lead. In recent years, food safety has been a priority in EU member states. Hence, the large number of regulations targeting veterinary food hygiene that are being adopted mainly by the European Food Safety Authority (EFSA) and other organisations. At present, hygienic limits are determined by the highest acceptable levels of contaminants in foodstuffs in the Commission Regulation 1881/2006/EC as amended and Decrees 68/2005 Sb. and 305/2004 Sb. of the Ministry of Health. As far as fish as food animals are concerned, the m...

The aim of the study was to evaluate mercury contamination at twelve outlet sites of rivers in the Czech Republic (Labe, Ohře, Vltava, Berounka, Sázava, Otava, Lužnice, Svratka, Dyje, Morava and Odra). As an indicator, we used muscle tissue of the chub (Leuciscus cephalus) caught at selected sites in 2007. A total of 96 fish were examined. Total mercury was determined by atomic absorption spectrophotometry using the AMA 254 analyzer and methylmercury was determined by gas chromatography with electron-capture detection. Total mercury (THg) and methylmercury (MeHg) concentrations ranged 0.039-0.384 mg·kg -1 fresh weight and 0.033-0.362 mg·kg -1 fresh weight, respectively. Mercury bound in methylmercury (Hg Me ) made up on average about 82.2% of total mercury. The highest mercury concentrations were found in fish from Obříství, a site on Labe (THg 0.263 ± 0.086 mg·kg -1 ; MeHg 0.256 ± 0.084 mg·kg -1 ). Mercury concentrations in fish from rivers that cross the borders of the Czech Republic (Labe, Odra and Morava) were low. The Czech Republic therefore does not contribute significantly to river pollution outside its national borders. Hazard indices of the sites monitored were well below 1, and reached 1.365 only in Obříství on Labe for fisherman's family members (i.e. in the case of annual consumption of 10 kg fish). This indicates possible hazards involved in eating meat of fish caught in that location. Based on PTWI for methylmercury, the maximum amount of fish meat allowed for consumption per week was calculated. The site with the lowest value was Obříství on Labe (0.44 kg). The results of this study present a partial contribution to health risk assessment on the major rivers in Czech Republic.Leuciscus cephalus, methylmercury/mercury ratio, THg, MeHg, hazard index, PTWI

The aim of this study was to synthesize cadmium telluride nanoparticles (CdTe NPs) modified apoferritin, and examine if apoferritin is able to accommodate CdTe NPs.