Determination of lead, cadmium and mercury in surface marine sediments andmussels

Lead, cadmium and mercury were determined in sediments and mussels, and the ability of these indicators to record metal variations in coastal marine e nvironment is described in this work. The results of an extended investigat ion of the status of three gulfs at Northern Greece are given, regarding th e content of these metals in surface sediments and Mytilus galloprovinciali s. The samples were collected during a four-year period. The total concentr ation of the above heavy metals was determined after digestion of the sampl es by suitable mixtures of acids, including nitric, perchloric and hydroflu oric acid. The digestion was carried out in a steel pressurised bomb with c losed teflon vessels. Lead and cadmium were determined by means of electrot hermal atomic absorption spectrometry (ETAAS), and mercury by cold vapour a tomic absorption spectrometry (CVAAS). The results were statistically evalu ated by analysis of variance, and emphasis was given to annual, seasonal an d spatial sources of variation. The annual changes during the last four yea rs and the spatial distribution of heavy metals load is also discussed.