Granulometry, mineralogy and trace elements of marine sedimentsfrom the Gulf of Milazzo (NE Sicily): evaluation of anthropogenic impact

Granulometry, mineralogy, and trace element concentrationsare determined in marine sediments from thirty-six sampling sites inthe littoral environment of the Gulf of Milazzo (NE Sicily). Sedimentsamples were collected in August 2008, along 18 seaward transects,at water depths of –10, –20 and –30 m, by using a Van Veen grab.Grain-size analysis shows predominance of sand (56%) and silt(35%) fractions with respect to clay (7%) and gravel (2%) fractions.Bulk mineralogical analysis documents the presence of quartz,micas, feldspars, calcite, and chlorite, which reflect erosionprocesses affecting the Kabilian-Calabrian Units. Concentrations ofmost trace elements in the deeper sediments were notably higherthan shallower ones, due to the gradual increase of the fine fraction(<63 mm). Concentrations of Cr, Ni, Pb and, at lesser extent, Zn andCu in the <63 mm fraction appear to be potentially hazardous,exceeding national and international regulatory guidelines, bothclose to the Milazzo industrial area and at Capo Rasocolmo. Traceelement mean values from the Gulf of Milazzo are comparable withthose measured in polluted sediments collected in the Gulf ofPalermo and Augusta Bay with a moderate enrichment in Zn. Differentsources of trace elements and different geochemical mechanismsare probably responsible of this distribution. Among these sourcesand mechanisms, local anthropogenic inputs, different contents oforganic matter, and surface water circulation may be invoked.