Mercury, arsenic, lead and cadmium in fish and shellfish from the Adriatic Sea

The aim was to measure concentrations of total mercury, total arsenic, lead and cadmium in common edible fresh fish and shellfish from various areas of the Adriatic Sea. Estimates of intake of these elements were made through seafood consumption by the general population. Samples were either wet digested for mercury and arsenic, or dry ashed for lead and cadmium analysis. Mercury was measured by cold vapour atomic absorption spectrometry (CV AAS) and arsenic, lead and cadmium by electrothermal atomic absorption spectrometry (ET AAS). Quality control procedures of analytical methods, which included analyses of dogfish muscle-certified reference material DORM-2, confirmed the acceptability of methods. The highest mercury and arsenic concentrations were found in hake (Merluccius merluccius) and the lowest in mackerel (Scomber scombrus). The respective values in hake were 0.373 +/- 0.075 and 23.3 +/- 3.6, and in mackerel 0.153 +/- 0.028 and 1.06 +/- 0.29 mg x kg(-1) fresh weight (mean +/- SD). Lead and cadmium concentrations were about 10 times higher in shellfish than in analysed fish. The highest lead and cadmium concentrations were found in mussel (Mytilus galloprovincialis) and the lowest in hake. Respective lead and cadmium values in mussel were 0.150 +/- 0.009 and 0.142 +/- 0.017, and in hake were 0.007 +/- 0.004 and 0.002 +/- 0.001 mg x kg(-1) fresh weight. The concentrations of analysed elements were below acceptable levels for human consumption set by the Croatian Ministry of Health, except for total arsenic. The estimated intake of those trace elements included in this study through seafood consumption by the general population did not exceed the provisional tolerable weekly intake recommended by the Joint FAO/WHO Expert Committee on Food Additives.