Mercury and methylmercury content in chub from the Svitava and Svratka Rivers at agglomeration Brno

Abstract

The aim of our study was to determine the total mercury and methylmercury contents in the muscle of indicator fish, to determine the total mercury contents in the sediment, and to evaluate the health risks associated with fish contamination. Chub (<i>Leuciscus cephalus</i> L.) were caught in seven localities on the Svratka and Svitava Rivers in the Brno agglomeration in 2007. The total mercury content was determined by atomic absorption spectrophotometry using an AMA 245 analyser. Methylmercury levels were determined by gas chromatography (using electron-capture detector) after acid digestion and extraction with toluene. The highest levels of total mercury and methylmercury contamination in the fish muscle (0.18 ± 0.09 mg/kg and 0.16 ± 0.09 mg/kg, respectively) were found at the Rajhradice site (the Svratka River, under the Brno city), whereas the lowest contents of mercury and methylmercury (0.08 ± 0.02 mg/kg and 0.04 ± 0.03 mg/kg) were detected at the Modřice site (the Svratka River). Total mercury content in the sediment ranged from 0.06 mg/kg to 1.38 mg/kg, the higher value having been detected in the sediment from the Svratka River at the Rajhradice site above the confluence with the Svitava River. The lowest content was discovered at Kníničky (the Svatka River). The hazard indices calculated for the selected localities showed no health risk to the common consumer or to the fishermen and their families.