## 4 Discussion  
The beginning of the CANOPAES project was complex, especially in the preliminary stages, due either to the difficulty in collecting information on the spread of polluted agricultural areas and to establishing fruitful collaborations with farmers. The results of the preliminary fast chemical analyses of the soil, realized during the starting selection of the sites, were confirmed by the obtained soil site characterization (Table 1). According to the regulations in force to identify the polluted agricultural areas, the pollution threshold established by the L.D. 152/2006 [44] was used as reference. This law, \"Norms Concerning the Environment\", regulates the Italian waste management system and considers public, private, and residential green areas. Indeed, only in 2019, did Italy regulate agricultural polluted areas, with the Ministerial Decree 46/2019 [51]. The law, issued by the Environmental Ministry containing regulations relating restoration and environmental safety of the areas destined to agricultural production. This law defined contamination thresholds for agricultural soils that, for some metals, are slightly higher than the previous ones. In the Sulcis-Iglesiente, the area considered in this study, where numerous contaminated sites have been identified, a lack of irrigation availability was found. This factor made it extremely difficult, if not impossible, for farmers, to join the project because in southern environments, hemp is an irrigated crop. For these reasons, and because of an awareness of the problems present in the polluted areas, to increase farmers participation, some information events were organized. Thanks to these events, 53 farmers applied to participate in the project but only three, who had the required requisites, finally joined the CANOPAES project. What was observed during this phase highlights that the experimentation performed in modality \"on farm trials\" allows to evaluate further concrete problems in conducting phytoremediation in contaminated areas. In phytoremediation applied in the field, several factors can affect the efficiency of the treatment or the plant responses [52]. With respect to assessments made in an experimental station, or in a confined test environment, difficulties that can be underestimated or not considered at all, may arise in the real context of polluted areas. By applying this method, bureaucratic or infrastructural problems (e.g., lack in efficient irrigation systems) could be revealed and, if possible managed, before the introduction of a new agricultural practice as phytoremediation. In the case of hemp, which is considered an irrigated crop, when evaluating the economic convenience of conducting phytoremedi  
\begin{table} \begin{tabular}{c c c c c c c} \hline \hline \multicolumn{1}{c}{**Factor**} & \multicolumn{4}{c}{**Heavy Metals**} \\ \hline  & \multicolumn{2}{c}{**Cd**} & \multicolumn{2}{c}{**Pb**} & \multicolumn{2}{c}{**Zn**} \\  & \multicolumn{2}{c}{**(mg kg–1)**} & \multicolumn{2}{c}{**(mg kg–1)**} & \multicolumn{2}{c}{**(mg kg–1)**} \\ \hline
3 Futura 75 & 1.70 & c & 7.06 & b & 129.8 & c \\
5 Uso 31 & 0.74 & d & 3.06 & d & 69.2 & d \\
5 Felina 32 & 0.01 & f & 2.65 & d & 15.2 & f \\
5 Futura 75 & 0.18 & e & 3.42 & cd & 29.8 & e \\
**Site \(\times\)Parts** & ** & ** & ** & ** & *** \\
3 Leaves & 6.80 & a & 8.77 & b & 952.3 & a \\
3 Stems & 4.02 & b & 7.51 & b & 177.7 & c \\
3 Roots & 3.52 & bc & 17.79 & a & 147.4 & d \\
3 Seeds & 3.01 & c & 1.54 & d & 250.1 & b \\
5 Leaves & 0.23 & d & 9.33 & b & 81.2 & e \\
5 Stems & 0.00 & e & 1.65 & d & 11.4 & f \\
5 Roots & 0.02 & e & 1.72 & d & 12.7 & f \\
5 Seeds & 0.02 & e & 2.80 & c & 82.5 & e \\
**Variety \(\times\)Parts** & ** & **n.s.** & & **n.s.** & \\
**Site \(\times\)Variety \(\times\)Parts** & ** & ** & **n.s.** & & \\ \hline \hline \end{tabular}   
*ation in contaminated soils, it is therefore necessary to account for the costs of restoring irrigation systems. The metal concentration in the soil sample of Site 1 (Table 1) were above the legal threshold levels for Pb [44].