Distribution of heavy metals in the Piscinas beach sediments (SW Sardinia, Italy)

Abstract

We have studied sediments of the Piscinas beach (SW Sardinia, Italy), which is supplied by two streams that wash mine dumps of abandoned lead and zinc mines at Montevecchio and Ingurtosu, situated inland from the supply basin of the beach itself. A study of the texture, mineralogy and geochemistry of the sediments was conducted for the purpose of assessing the possible influence of the mine waste on the composition of the sediments, looking for any anomalous enrichments in heavy metals. Furthermore, to evaluate and quantify metal release into the sea, samples of Posidonia oceanica, a bioaccumulator marine plant, were also examined. The results indicate that the distribution of heavy metals in the foreshore sediments is particularly affected by the contribution of the streams, while in the shoreface the distribution is affected by the currents that disperse the sediments both out to sea and southwards. The metal contents of the Posidonia oceanica are correlated with the different stages of activity of the mines.