MANAGEMENT STRATEGIES OF CONTAMINATED SEDIMENTS IN A SITE OF NATIONAL INTEREST (SIN)*

The management of contaminated sediments represents one of the most critical problems in coastal marine ecosystems. In recent years, many efforts have been devoted to the development of green and sustainable decontamination technologies that can also be used also in situ. Marine sediments, derived from dredging, have increasingly been considered a source of materials for both civil and industrial uses. The management of contaminated sediments in marine areas with high environmental risk, such as that of Taranto, is however largely linked to the objectives to be achieved. For example, the expansion of the port area in the Mar Grande basin to deepen the seabed involved the dredging of large volumes of sediment, especially contaminated on the surface. For the latter, appropriate treatments have been used to reduce the load of pollutants. For less contaminated deep sediments, deposition in a storage tank was chosen. Dredging actions have a strong impact on the marine environment and affect biodiversity. Until a few decades ago, it was thought that the removal of contaminated sediments would be the preferred solution to be applied in various environments. The volumes to be removed, and the treatment costs, have suggested that removal can sometimes have a significant anthropogenic and economic impact. At present, there is a growing awareness of the fact that if not necessary, sediment dredging can have other valid alternatives, especially in ecosystems where important biological communities are present. In confined marine basins, environments such as the Mar Piccolo of Taranto, it is evident that extensive dredging could represent a risk due to the resuspension of contaminants with influences on mussel farming. Capping and/or Monitored Natural Recovery (MNR) could represent an alternative. This work illustrates these various alternatives.