Kamila Kružíková

Assessment of contamination of the Svitava and Svratka rivers in the Czech Republic using selected biochemical markers

The aim of the present study is to assess aquatic ecosystem contamination using selected biochemical markers: cytochrome P450, ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST), tripeptide glutathione, vitellogenin, and 11-ketotestosterone in chub (Leuciscus cephalus L.). Seven locations on the Svitava and Svratka rivers (in the Brno conurbation, Czech Republic) were assessed. The results were compared with the levels of the most important inductors of these biomarkers: organic pollutants hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), DDT and its metabolites, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons in bottom sediment, fish muscle, and semipermeable membrane devices (SPMDs) and metals in sediment. The highest levels of pollutants were observed at sites situated downstream from Brno, especially at Modrice and Rajhradice. Significant positive correlations (p < 0.05) were found between EROD activity and HCH concentration in SPMDs, and also between GST and EROD activity with HCB concentration in muscle, after adjusting for age.

Mercury speciation in fish muscles from major Czech rivers and assessment of health risks.

The aim of this work was to determine the mercury and methylmercury content in muscle tissue of chub (Leuciscus cephalus L.), to assess the health risks of eating the fish and to determine the number of fish meat servings that are suitable for weekly consumption. Total mercury concentrations were determined using a single-purpose atomic absorption spectrophotometer AMA 254. Methylmercury concentrations were determined by gas chromatography. The location where the highest total mercury concentrations in fish muscle tissues were found was the Vltava - Vraňany (0.236±0.1001mg/kg(-1)), and the highest methylmercury concentration was found at the Labe - Obříství (0.231±0.1056mg/kg(-1)). The conclusion based on the data ascertained is that the locations from which the lowest number of fish meat servings can be eaten are the Vltava - Vraňany and the Labe - Obříství. The results of this study helped evaluate contamination levels of rivers that flow out of the Czech Republic.

Distribution of mercury in rainbow trout tissues at embryo-larval and juvenile stages.

The aims of the study were to determine total mercury concentrations in “rainbow trout Oncorhynchus mykiss (Walbaum)” at their embryo-larval and juvenile stages and to assess mercury concentration dynamics in individual tissues. Samples of rainbow trout were collected at two-month intervals over a period of 18 months (one stock production cycle) at the Velká Losenice trout farm. Feedstuff samples were collected at the same time and analyzed for mercury concentrations. Tissue mercury concentrations were determined in muscle, liver, and kidneys. Analyses were performed using the AMA 254 atomic absorption spectrophotometer. The lowest mercury concentration was found in 14-day-old embryos (hard roe), and the highest concentrations in muscle tissue, liver, and kidneys at the end of monitoring, that is, in rainbow trout aged 18 months. The amount of mercury in feedstuffs showed an increasing trend and ranged between 0.0126 and 0.0859 mgkg−1. A significant effect (P < 0.001) of mercury intake on mercury concentrations in muscle tissue, liver, and kidneys was demonstrated. Muscle mercury concentrations in 18-month-old market-ready rainbow trout of 0.128 ± 0.048 mgkg−1 met the criteria for fish meat hygiene.