Toxic and essential elements in fish from Nordic waters, with the results seen from the perspective of analytical quality assurance

Fish from fresh, brackish and marine waters were analysed for their levels of Pb, Cd, Cr, Ni, Co, Zn, Crc, Mn, As and Se in muscle tissue. Various qua lity control procedures were implemented during the survey and the results were compared with those from several other surveys, most of which were car ried out during the 1990s. It was noted that several elements varied widely both within and between studies. A systematic examination of a large numbe r of surveys and ranking of their quality level indicated that a lack of qu ality control procedures often results in high or varying results. This may have serious consequences when results are used as a basis for, for exampl e, legislation or intake recommendations.