engleski

Total content of mercury, lead and cadmium in common edible fish and mussels from the Adriatic sea

Except for the occupationally exposed individuals consumption of fish is the main source of human exposure to mercury. Also exposure to lead and cadmium through fish is significant especially for the population living near the coast or on the islands. The aim of this study was to determine the total mercury, lead and cadmium concentrations of the common edible species of fresh fish and mussel from the different parts of the Adriatic Sea. Only muscular fish tissue, free of bones and total mussel tissue was taken for analysis. Total mercury concentration was measured by cold vapour atomic absorption spectrometry (Mercury Monitor LDC, UK) after digestion of sample by heating in concentrated nitric acid at 80  C, using closed glass tubes. Lead and cadmium were determined by electrothermal atomic absorption spectrometry (Varian model SpectrAA-300, Austria) after dry ashing of sample at 450  C. Deuterium lamp as background correction was used. Detection limits of analytical methods were 0.33 ng Hg ml-1, 0.47 ng Pb ml-1 and 0.07 ng Cd ml-1 for analyte solution or based on a sample wet weight: 3.3 ng Hg g-1, 0.94 ng Pb g-1 and 0.14 ng Cd g-1. Precision of the methods within a day, calculated as coefficients of variation of 10 analysis of the same fish sample were 17%, 38% and 23% for mercury, lead and cadmium, respectively. Methods accuracy was tested by the parallel analysis of a dogfish muscle reference material (DORM-2 from the National Research Council of Canada). The results were in good agreement with the certified values. The ranges of mercury, lead and cadmium concentrations in fish were 142-252 ng g-1, 9.6-44.1 ng g-1 and 5.1-49.1 ng g-1, respectively and mean metal concentrations in mussel were 134 ng Hg g-1, 121 ng Pb g-1 and 130 ng Cd g-1. The levels of analysed elements in fish and mussel did not exceed maximum permissible levels of mercury, lead and cadmium in fish and mussel set by the Croatian Ministry of Health. The moderate intake of fish and mussel does not exceed Provisional Tolerable Weekly Intake set by the Joint FAO/WHO Expert Committee on Food Additives.

human exposure; mercury; cadmium; lead; fish; mussels; atomic absorption spectrometry; certified values; provisional tolerable weekly intake

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