Volume 6, Issue 7 (July 2009)
Remediation of Harbor Sediments Contaminated by Polycyclic Aromatic Hydrocarbon and Metals
The Taranto harbor area is included in the Italian National Priority List of contaminated sites. For the enlargement works of the fourth quay in the Taranto harbor, the remediation of contaminated sediments shall be carried out. The existing jetty was devoted to unloading of iron ore for the nearby ILVA steel mill. The sea depth in the intervention area ranges between 2 and 10 m and contaminated sediments (up to 3 m thick) are deposited on a layer of overconsolidated hard clay. The characterization activity of the area was carried out by ICRAM (a public sea research institute) indicating the presence of both organic (polycyclic aromatic hydrocarbon) and inorganic (metals) contaminants in the sediments. The remediation project consists of the two following phases: Mechanical dredging of highly contaminated sediments (15.500 m3) using low-turbidity tools and hydraulic excavation of sediments with a lower level of contamination (360.000 m3). Abiding by national regulations, the highly contaminated sediments will be treated in a dedicated plant while the sediments with a low level of contamination will be deposited in large ponds. The impact of dredging activities shall be mitigated by specific precautions. The possibility of beneficial reuse of dredged material was also studied, especially for low contamination sediments, as well as compatibility with national regulations. A specific monitoring plan will be enacted for the entire duration of remediation works, which are expected to start in 2010.