# DPSIR Model Applied to the Remediation of Contaminated Sites. A Case Study: Mar Piccolo of Taranto
## 6 States  
### Marine Sediment Characterization  
There were several characterizations of marine sediments in the last few decades. From 2005 to 2009, the Italian institute for environmental protection and research (ISPRA), carried out a sampling campaign in both bays of the Mar Piccolo for a total number of 1517 samples, as shown in Figure 6.  
The following analyses were performed on the sediment samples:  
* Granulometry, water content, specific weight, pH, redox potential, metals and trace elements (Al, As, Cd, total Cr, Fe, Hg, Ni, Pb, Cu, Zm, V), polychlorinated biphenyl, organochlorine pesticides, PAHs, light hydrocarbons C \(\leq\) 12, heavy hydrocarbons C \(>\) 12, total nitrogen, total phosphorus, cyanides, and total organic carbon (TOC) on 1023 samples;
* Organotin compounds on 106 samples;
* Aromatic solvents (BTEX), phenols on 112 samples;
* Sb, Cr VI, Se and St on 138 samples;
* Microbiological parameters (fecal streptococci, salmonella, septic-reducing spores:) on 128 samples;
* Dioxins and furans and asbestos on 23 samples;
* Ecotoxicological tests (Vibrio fischeri e Brachionus placatilis) on 20 samples. Figures 7 and 8 show chemical concentrations with reference to the Italian Legislative Decree [43] and the ICRAM intervention values for the Taranto area [44]. Observing the analytical results, the sediment environmental quality state were complex and characterized mainly by inorganic pollutants in high concentrations in all the First Bay and some parts of the Second one. All surficial layers (0-50 cm) appeared to have a spread contamination by heavy metals and hot spots in some areas (Military Arsenal and Citro Cittello etc. ), as shown in Figure 7. Organic compounds are present but in a smaller percentage both in terms of area and amount, as shown in Figure 8. For what concerns metals and trace elements, mercury (Hg) is the element which showed the highest concentrations in most samples. Even zinc (Zn) exceeded many of the concentrations in the limit intervention values [44] in both bays. Copper (Cu) and lead (Pb) showed similar concentration trends both in surficial and deep levels. Arsenic appeared in the first centimeters of sediments. For what concerns organic compounds, their concentrations were lower than metals, and PCBs were the most abundant, especially in the first  
Figure 6: Maps of the sampling points from 2005 to 2010 [42]. bottom layer (0-50 cm) in the First Bay, as shown in Figure 8. A similar distribution is given by PAHs, mostly present on the north-west side of the First Bay. Total hydrocarbons were present especially in the first layer of the First Bay in the area for mussel farming, near both the bridges on the west side but also in the entrance/exit channel between the two Bays. In 2016, the Special Commissioner for urgent measures of remediation, environmental improvements, and redevelopment of Taranto, appointed by the Italian government, promoted an investigation campaign aimed at the multidisciplinary characterization of the First Bay. In the field of the actions promoted by the Italian Government to select the most sustainable remediation strategies, a multidisciplinary investigation of the site was carried out, involving the reconstruction of the geological set-up of the basin, the analysis of the chemical contamination, and the geo-mechanical properties of the sediments collected up to 30 m below the seafloor [45]. In particular, chemical analyses to determine the concentrations of metals, PAHs, and PCBs in the 3m-deep samples were carried out [46]. Figure 8: Organic compound concentrations map (adapted from [42]). Figure 7: Inorganic compound concentrations map (adapted from [42]). It was observed that metal concentrations decreased with sampling depth, as shown in Figure S3 in Supplementary Material. Except for Ni and V, all the other metal concentration levels (in at least one site) were higher than the limits of site-specific law [46].