Biomonitoring of heavy metals in fish from the Danube River

The Croatian part of the Danube River extends over 188 km and comprises 58 % of the country’s overall area used for commercial freshwater fishing. To date, the heavy metal contamination of fish in the Croatian part of the Danube has not been studied. The main purpose of this study was to determine heavy metal levels in muscle tissue of sampled fish species and to analyze the measured values according to feeding habits of particular groups. Lead ranged from 0.015 μg−1 dry weight in planktivorous to 0.039 μg−1 dry weight in herbivorous fish, cadmium from 0.013 μg−1 dry weight in herbivorous to 0.018 μg−1 dry weight in piscivorous fish, mercury from 0.191 μg−1 dry weight in omnivorous to 0.441 μg−1 dry weight in planktivorous fish and arsenic from 0.018 μg−1 dry weight in planktivorous to 0.039 μg−1 dry weight in omnivorous fish. Among the analyzed metals in muscle tissue of sampled fish, only mercury exceeded the maximal level (0.5 mg kg−1) permitted according to the national and EU regulations determining maximum levels for certain contaminants in foodstuffs, indicating a hazard for consumers of fish from the Danube River.