# DPSIR Model Applied to the Remediation of Contaminated Sites. A Case Study: Mar Piccolo of Taranto
## 8 Responses
### Remediation Technologies  
The technological response in terms of remediation interventions is closely related to a new development strategy for the study area. As described above, Taranto has always had an industrial vocation against agricultural and tourist activities. Lately, with the crisis in heavy industry and steel, a new development strategy has been discussed. There are several hypotheses, among which are those of converting part of the heavy industry towards greener forms and, at the same time, promoting forms of circular economy [27] or abandoning heavy industry to promote tourism, not extensive agricultural activities with less environmental impact and the fish industry. Any new development strategy must include a technological response in terms of remediation. In order for these remediation interventions to be long-lasting, the current pressures on the study area should be identified and controlled/regulated, starting with the control of discharges. The remediation interventions described below are part of this context. Extensive research has been conducted on remediation treatment technologies. In our study, we consulted both project reports and scientific articles [79; 80; 81; 82; 83; 84; 85]. In situ remediation with a capping system involves the placement of a clean substrate to isolate contaminants (physical capping) or reactive amendments to chemically react and reduce contaminant availability and mobility (reactive capping) [86]. Reactive amendments tend to increase contaminant binding by modifying sediment geochemistry and can provide degradation and/or adsorption of contaminants while allowing upward groundwater flow. The results of the experimental investigation have shown that reactive capping could represent an interesting option for in situ remediation technology for contaminated sediments in the Mar Piccolo [87]. Reactive Permeable Mats (RPM) with organoclay (OC) or active carbon (AC) were used. RPM represents an innovative capping technology and consists of using the amendments encapsulated in a non-woven core matrix, bound between two geotextiles [88]. After 20 days from the placement of the capping system, the results show that PAH concentrations in water decreased from an initial 0.1 \(\upmu\)g/L to near 0.04-0.06 \(\upmu\)g/L for the column apparatus with a cap. Moreover, a reduction of 60% (RPM with AC) and 40% (RPM with OC) in the original PAH contamination was recorded. The effectiveness of different capping materials for PAH contaminated marine sediments was evaluated by [PERSON] et al. [25] through numerical modelling in a long observation period (\(\geq\)10 months). The results demonstrated that, without the capping system, PAH concentrations in water increased over the time, reaching high levels of contamination far above the Italian regulatory limits in water. Conversely, in the condition with capping, the long-term effectiveness over time was guaranteed, not reaching the threshold limit set at 0.05 \(\upmu\)g L\({}^{-1}\). Concerning ex situ technologies, dredging and subsequent chemical treatments are the most common techniques adopted in a remediation plan. However, sustainability and protection of the marine ecosystem should be the first objective for any decision-maker. Dredging, in fact, entails sediment, resuspension phenomena, and off-site sediment transport for treatment or disposal [89]. For heavily polluted sediments, or if dredging is compulsory to reach a desired bathymetric level, ex situ technologies for sediment remediation become the most appropriate choices. However, after dredging any remaining contaminants in seabed, sediments can be sequestered or isolated with either a low-permeability cap or a permeable in situ layer. In these cases, the \"beneficial reuse\" of dredged materials is highly encouraged [90]. The stabilization/solidification (S/S) of contaminated sediments is an appealing technology for both chemical and mechanical improvement (i.e., contaminant immobilization, compressibility reduction, and strength improvement). [PERSON] et al.