## 3 Results
### Sites Pedological Description and HMs Distribution in Soil
The entire area was affected by the flooding of the Sitzerri River that deposited, in its floodplain, high amounts of mining wastes from Montevecchio [47; 49; 50]. The Montevecchio mineral district activity, started in 1848 and closed definitively in 1991, was dedicated to extract and process PbS and ZnS. This experimental site was situated in irrigated land, and it was usually grazed or cultivated. The area was served by public irrigation infrastructure, but it was very damaged before the cultivation started. The soil of the Site 2 was classified as Fluventie Dystroxerept, fine-loamy, mixed, superactive, with Ap1, Ap2, 2 Bw, 3C1, 4C2, 5C3, 5C4, 6C horizons. The contamination level was Zn > Pb > Cd with total values (in the topsoil) of 441, 422 and 3.7 mg kg\({}^{-1}\) respectively. The order of DTPA-extractable metal concentrations was Zn > Pb > Cd with 115, 106 and 2.32 mg kg\({}^{-1}\) The mobility of metals in the site, evaluated as the percentage of the total metal content extracted with DTPA, was 26.07% Zn, 25.11% Pb and 62.70% Cd. Site 3 (39\({}^{\circ}\)37\({}^{\prime}\)8.76\({}^{\prime\prime}\) N-8\({}^{\circ}\)38\({}^{\prime}\)6.48\({}^{\prime\prime}\) E, 32 m a.s.l.) was in the same area as Site 2. The main characteristics and management of the area are close to those described for Site 2. The soil of the Site 3 was classified as Humic Haploxerept fine--loamy, mixed, superactive, thermic with Ap1, Ap2, Bw, C, 2C, 3C horizons. The contamination level was Zn > Pb > Cd with total values (in the topsoil) of 1076, 999 and 9.2 mg kg\({}^{-1}\) respectively. The order of DTPA-extractable metal concentrations instead was Pb > Zn > Cd with 258, 212 and 5.9 mg kg\({}^{-1}\). The mobility of metals in the site, evaluated as the percentage of the total metal content extracted with DTPA, was 19.7% Zn, 25.82% Pb and 64.13% Cd. Site 4 (39\({}^{\circ}\)38\({}^{\prime}\)50.87\({}^{\prime\prime}\) N-8\({}^{\circ}\)40\({}^{\prime}\)53.13\({}^{\prime\prime}\) E, 21 m a.s.l.) was located in agricultural land, irrigated from decades, and it is usually cultivated with feed crops such as alfalfa, corn, sorghum. Public irrigation infrastructure serves this land. The soil of the Site 4, one of the control sites, was classified as Fluventie Haploxerept, coarse--loamy, mixed, superactive, thermic with Ap, C, 2 Bw, 2C, 3C horizons. The level of HMs was Zn > Pb > Cd with total values (in the topsoil) of 145, 50.7 and 1.01 mg kg\({}^{-1}\) respectively. The order of DTPA-extractable metal concentrations instead was Pb > Zn > Cd with 2.51, 5.2 and 0.21 mg kg\({}^{-1}\). The mobility of metals in the site, evaluated as the percentage of the total metal content extracted with DTPA, was 1.73% Zn, 10.25% Pb and 20.79% Cd. Site 5 (39\({}^{\circ}\)5\({}^{\prime}\)49.42\({}^{\prime\prime}\) N-8\({}^{\circ}\)32\({}^{\prime}\)15.62\({}^{\prime\prime}\) E, 5 m a.s.l.) was an agricultural area, that is the other control site, served by a public irrigation system for a long time and was usually cultivated by irrigated feed crops typical of the area, such as corn and alfalfa. The soil of the Site 5 was classified as Pachic Calciexroll coarse--loamy, mixed, semiactive, thermic with Apk, 2 Bk, 3 Bw, 4 AB, 5 Bwb horizons. The level of HMs was Zn > Pb > Cd with total values (in the topsoil) of 61.8, 24.1 and 0.4 mg kg\({}^{-1}\) respectively. The order of DTPA-extractable metal concentrations instead was Pb > Zn > Cd with 4.18, 2.25 and 0.12 mg kg\({}^{-1}\). The mobility of metals in the site, evaluated as the percentage of the total metal content extracted with DTPA, was 3.64% Zn, 17.34% Pb and 30% Cd. To better understand the pollution levels in the experimental sites, Table 1 shows the distribution of the total and available HMs contents. The average values of HMs for each soil are reported in this table, while more detailed information is given in the Supplementary Materials (S.M.) file.