Mercury content in the muscle of fish from the Elbe River and its tributaries

The main aim of the present study was to assess the mercury contamination of the Elbe River and its tributary the Vltava River. Mercury concentrations in fresh fish muscles were used for the contamination assessment. The samples were collected in 1999, 2002 and 2003 at 7, 2 and 1 collection sites from the Elbe River, Vltava River and Blanice River (tributary of the Vltava River), respectively. Samples of bream (Abramis brama L.), perch (Perca fluviatilis L.) and chub (Leuciscus cephalus L.) muscle were collected at the monitored sites. A single-purpose mercury analyser AMA 254 was used to determine the total mercury content in the muscle tissue of fish. Average concentrations of mercury in the muscle of bream, perch and chub were in the range 0.172-0.852 mg/kg, 0.077-1.07 mg/kgand 0.141-1.631 mg/kg,respectively. The highest values of total mercury content were found in fish from the localities Obříství and Lysá nad Labem (P < 0.05; P < 0.01, respectively) in the river section from 120th to 160th river kilometre. The highest value of total mercury content (2.56 mg/kg) in the fresh muscle of chub was in the Obříství vicinity. It poses a high risk for consumers, considering the average consumption of 10 kg fish per capita/year (hazard index 3.0). On the other hand, total mercury contamination decreased in the localities Děčín and Hřensko (15th-5th r. km) in the period 1999-2003. The findings in 2003 indicated that the disastrous floods in 2002 did not significantly influence the mercury contamination of fish.