PARENT SESSION
38 - Soil and Sediment Contamination
8:00 AM to 6:30 PM, Tuesday, 14 May 2002
Exhibition Area

(38-18) Distribution of PCBs, PAHs and heavy metals in bottom sediments of the Eastern Mediterranean Sea.

Menchi, Valentina^*,1, Balocchi, Cristiana¹, Pozo, Karla¹, Perra, Guido¹, Graziosi, Marinella¹, Focardi, Silvano¹, ¹ University of Siena, Siena, Italy

ABSTRACT- PCBs, PAHs and heavy metals are some of the most toxic, persistent and life-threatening compounds in the environment. For many years, the aquatic ecosystem has been the sink of pollutants, which bind to sediment and then accumulate, so bottom sediments are often the best available medium for long term monitoring. Surficial sediment samples were taken in June 2001 at various offshore, coastal and estuarine sites throughout the Northern Adriatic Sea. Concentrations of PCBs, PAHs and some heavy metals (Cd, Pb, Cr, Ni, Cu, Zn, Fe) were determined. The highest PCB concentrations were found at the rivers Isonzo (99.28 ng/g d.w.), Po (76.66 ng/g d.w.) and Adige (44.61 ng/g d.w.), whereas the lowest were detected far from the coast (19.50 ng/g d.w.). The highest concentrations of PAHs in the sediments were found at river Piave outflow (328.99 ng/g d.w.), while the open sea area (0.47 ng/g d.w.) was lowest. The highest values of metals were found in the Gulf of Trieste (means: Ni 86.6; Pb 23.3; Cu 18.3; Fe 15012 g/g d.w.) and at the Adige River outflow (means: Zn 92.8; Pb 27.03; Cu 26.4; Cd 0.589; Fe 16769 g/g d.w.), while the lowest were detected at the Livenza River outflow (means: Zn 27.5; Pb 6.56; Cu 5.22; Cd 0.114; Fe 7440 g/g d.w.). Data analysis clearly shows a typically decreasing gradient of contamination from the coast toward the open sea area, indicating that the main sources are attributed to river transport, industrial and sewage discharges and atmospheric deposition.

Key words: sediments, PCBs, PAHs, heavy metals