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Speciace rtuti v rybích tkáních
Hrůzová, Marie
The diploma thesis is focused on the issue of contamination of freshwater fish species by chemical forms (species) of mercury. To monitor mercury speciation in fish tissues, four locations in the Czech Republic were selected - the Záskalská reservoir, Rybníkářství Pohořelice a.s., the Smrk pond, and the Lipolec pond. The Záskalská reservoir is located near the historic cinnabar mine, hence an increased risk of fish contamination was expected. No significant source of mercury contamination was identified in the other aquatic ecosystems. Four fish species - perch (Perca fluviatilis), roach (Rutilus rutilus), pike (Esox lucius), and European eel (Anguilla anguilla) were caught for analysis. Fish tissue samples (muscles, gills, liver, and skin) were analyzed for total mercury concentrations using atomic absorption spectrometry on an AMA 254 and for individual mercury species using High-performance liquid chromatography with atomic fluorescence detection (HPLC-CV-AFS). The highest total mercury contents were found in the muscles of fish from the contaminated Záskalská reservoir. The muscle tissues of pike, perch, and roach from the Záskalská reservoir exceeded the limit set by Regulation No. 1881/2006 EC. Only inorganic mercury species (Hg2+) and methylmercury species (MeHg+) were found in fish tissues. The highest amounts of methylmercury were found in muscle tissues (63-96 %), followed by skin (55-90 %), liver (31- 82 %), and gills (42-81 %). Statistically significant differences in mercury species content were compared between predatory and non-predatory fish, contaminated and non-contaminated locations, and the thesis also assessed the impact of age, species, and diet on the speciation of mercury in fish tissues.
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