## 3 Results
### Sites Pedological Description and HMs Distribution in Soil  
The main pedological characteristics of each experimental site were described and classified, by the soil profiles, according to the Soil Taxonomy [45]. For each horizon discovered in the profiles, physical and chemical properties and Zn, Pb, Cd contents, were described. Total and available Cd, Pb and Zn contents in the 5 soils are shown in Table 1 and more detailed data are reported in Supplementary Materials (S.M.). Site 1 (39\({}^{\circ}\)32\({}^{\prime}\)52.74\({}^{\prime\prime}\) N-8\({}^{\circ}\)46\({}^{\prime}\)16.43\({}^{\prime\prime}\) E, 46 m a.s.l.) was located close to a lead smelter of the San Gavino city industrial area. The industrial site of San Gavino is subordinated to a specific Italian law for contaminated Sites that defines the Sites of National Interest (SIN). Specifically, the San Gavino site is included by the law into the SIN of Sulcis-Iglesiente-Guspinese [46]. The San Gavino lead smelter started in 1932, in the past processed Pb and Zn minerals from the Montevecchio mine [47]. After an inactive period, the San Gavino \begin{table}
\begin{tabular}{l c c c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Cd Total**} & \multicolumn{2}{c}{**Cd Avail.**} & \multicolumn{2}{c}{**Pb Total**} & \multicolumn{2}{c}{**Pb Avail.**} & \multicolumn{2}{c}{**Zn Total**} & \multicolumn{2}{c}{**Zn Avail.**} \\  & \multicolumn{2}{c}{**(mg kg\({}^{-1}\))**} & \multicolumn{2}{c}{**(mg kg\({}^{-1}\))**} & \multicolumn{2}{c}{**(mg kg\({}^{-1}\))**} & \multicolumn{2}{c}{**(mg kg\({}^{-1}\))**} & \multicolumn{2}{c}{**(mg kg\({}^{-1}\))**} & \multicolumn{2}{c}{**(mg kg\({}^{-1}\))**} \\ \hline
**Site 1** & 1.94 & c & 0.67 & c & 117.0 & c & 42.7 & b & 143.9 & c & 5.5 & c \\
**Site 2** & 4.17 & b & 2.46 & b & 308.0 & b & 74.8 & b & 572.5 & b & 115.5 & b \\
**Site 3** & 8.71 & a & 5.86 & a & 751.9 & a & 162.4 & a & 940.3 & a & 174.2 & a \\
**Site 4** & 0.84 & c & 0.19 & c & 52.0 & c & 6.3 & c & 146.1 & c & 2.7 & c \\
**Site 5** & 0.37 & c & 0.10 & c & 20.9 & c & 3.7 & c & 56.1 & c & 1.6 & c \\ \hline \hline \end{tabular}  
For any factor, means followed by the same letter do not differ significantly at \(p\leq 0.05\) by LSD test.  
\end{table} 
Table 1: Total and available Cd, Pb, and Zn in soil of CANOPAES project: Sites 1–3 potentially polluted; 4,5 non-polluted. Figure 1: Case Study and selection of experimental fields: (**a**) polluted or mining georeferenced area, and request to participate by farmers in 2017 and 2018 (magenta symbol); (**b**) the Sulcis-Iglesiente study area and the five experimental fields, red ones are polluted sites, whereas yellow are control-sites. thermal refinery is nowadays productive and decopperizes lead to obtain refined Pb as well as other products occurring with lead, silver, gold, and bismut. The highest levels of lead in the blood of people in the San Gavino population (adults and children) were found during the 1980-1981 monitoring years [48]. The area of interest for this study was classified for agricultural uses by the law, but indeed it was not utilized for a long time. Undisturbed vegetation, with predominantly herbaceous flora, covered the soil until the study started. The soil of Site 1 was classified as Vertic Haploxerept, fine-loamy, mixed, superactive, thermic, with Ap, Bkss, Bkss2, C horizons. The contamination level was Pb > Zn > Cd with total values (in the topsoil) of 147, 125 and 2.4 mg kg\({}^{-1}\) respectively. The order of DTPA-extractable metal concentrations was Pb > Zn > Cd with 54.4, 4.86 and 0.95 mg kg\({}^{-1}\). The mobility of metals in the site, evaluated as the percentage of the total metal content extracted with DTPA, was 3.88% Zn, 37% Pb and 39.58% Cd. Site 2 (39\({}^{\circ}\)37\({}^{\prime}\)5.65\({}^{\prime\prime}\) N-8\({}^{\circ}\)38\({}^{\prime}\)2.93\({}^{\prime\prime}\) E, 33 m a.s.l.) was located just 150 m outside of the areas amenable to the law for contaminated Sites of National Interest [46].