Toxic trace elements in Chilean seafoods: development of analytical quality control procedures

Chile is a well known producer and exporter of shell fish. These seafoods, like other specimens of marine origin, are susceptible to environmental and other contamination by trace elements, including toxicants. Therefore, adequate analytical quality assurance is mandatory before accepting analytical results. In this context, the use of at least two independent methods of determination and validation with certified reference materials (CRM) provides acceptable criteria for judging the reliability of the data. This paper describes sample treatments and analytical procedures for Cd, Cu and Hg determinations in mollusc samples. Three independent analytical techniques, namely differential pulse anodic stripping voltammetry, neutron activation analysis and atomic absorption spectrometry, were used. CRM standards of the IAEA, NIST and BCR were analyzed to evaluate quality assurance. Following the quality control phase, the concentrations of cadmium, copper and mercury in fresh and canned mollusc samples Tagelus dombeii and Semelle solida (Navajuelas and Almejas chilenas respectively) from different locations were determined.