The industrial zone of Porto Marghera is one the most important "contaminated sites
of national interest" (SIN) in Italy, being identified as an area of high environmental
risk. The site includes a wide shallow water area of the Venice Lagoon extending toward
the city of Venice, which was investigated in order to acquire information on the
pollutant level and distribution. Grain-size, heavy metal, nutrient, and organic micropollutant
concentrations were determined in the surface sediment layers (0-5 and 5-10 cm depths)
of 51 sites. A generally low contamination was found, except for Hg concentration,
which increases the toxicological risk in most of the sites of the area, according
to the results of a comparison with Sediment Quality Guidelines. A heavy pollution
fingerprint (Cd, Cu, Hg, Pb, and Zn up to 15.2, 257, 11.9, 248, and 3010 mg/kg d.w.,
respectively) was instead found near the Tresse Island, which is ascribed to the spill
of pollutants from the contaminated sediment disposed therein. Grain-size and heavy
metal profiles down to a depth of 40 cm in eight selected sites, finally show a probable
decrease of the pollution affecting the area in recent years.