## 3 Results and Discussions  
Among the analyzed potentially toxic elements (PTEs), Zn, Cu and Ni showed the highest concentrations in AdV bulbs: 12.9-44.2, 2.4-6.6 and 0.72-8.76 mg/kg dw, respectively (Table 3). Chromium and Pb had levels normally in the range 0.1-0.5 mg/kg dw, while Co, U, V showed lower concentrations from 0.02 to 0.12 mg/kg dw. Levels of Cd and Sb in AdV bulbs were in the wide range <0.001-0.29 and <0.001-0.06 mg/kg dw respectively, with values below the limit of detection (LOD) in 50% of samples for Cd and 15% for Sb. Arsenic and Tl had very low concentrations, always below the LOD of 0.001 mg/kg dw. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{2}{c}{**Contamination Factor (CF)**} & \multicolumn{2}{c}{**Geo-Accumulation Index (I\({}_{\text{geo}}\))**} \\ \hline CF \textless{} 1 & Low contamination & 0 \textless{} I\({}_{\text{geo}}\) \textless{} 1 & Uncontaminated \\ \(1\textless{}\textless  
The concentrations of PTEs in AdV bulbs are comparable with those reported for elephant garlic grown in uncontaminated sites [11; 30], and much lower than those measured in this garlic species cultivated in contaminated soils [31]. In particular, the comparison with the few data available for PTEs in elephant garlic grown in uncontaminated soils, showed that AdV has very lower concentrations of As and Cr, similar levels of Cu and Zn and slightly higher concentrations of Cd and Pb. Nickel contents in AdV bulbs are one order of magnitude higher than in elephant garlic from uncontaminated sites, but still 10 times lower than in plants grown in contaminated soils (Table 3). Extending the comparison to common garlic for the problematic PTEs (Cd, Pb, Ni) [8; 11; 32; 33; 17; 34], it emerged that Ni and Pb contents in AdV bulbs are within the respective range in common garlic cultivated in uncontaminated sites (0.03-6.3 mg/kg dw for Ni; 0.08-0.54 mg/kg dw for Pb). Cadmium concentrations in AdV are both lower than and similar to the usual levels (0.02-0.07 mg/kg dw) reported for common garlic, except for the highest contents (0.12-0.29 mg/kg dw) measured in AdV bulbs from one of the investigated cultivation fields. Furthermore, the concentrations of PTEs in AdV are comparable with those reported for the \"reference plant\" [35], with the exceptions of Cd, Ni and U which had concentrations 1.4, 2.5 and 7 times higher, respectively, based on the average value, and 5.8, 9 and 6 times higher, respectively, considering the maximum concentration measured. The European Legislation [36] and the FAO/WHO Codex Alimentarius [37] indicate a maximum permissible content in vegetables such as elephant garlic, of 0.1 and 0.05 mg/kg fw, respectively, for Cd and 0.1 mg/kg fw for Pb. Concentrations of Cd and Pb in AdV were calculated on a fresh weight basis considering an average water content of 61.8% measured in our cloves, and resulted, on average, 0.03 mg/kg fw for Cd and 0.1 mg/kg fw for Pb; thus, within the legal limits. However, the highest Cd and Pb concentrations in AdV (0.11 mg/kg fw for Cd and 0.16 mg/kg fw for Pb) were higher than the legal limit. As far as Ni is concerned, although garlic has been included by [PERSON] et al. [38] in the list of food that contain high amounts of this PTE, values of tolerable daily intake for Ni (considering one clove of ca. 25 g of elephant garlic and a body weight of 70 kg) are well within the 13 ug/kg of body weight suggested by the European Food Safety Authority [39], even considering the highest concentration measured (8.7 mg/kg dw). DIPTE values of each PTE in elephant garlic from the Valdichiana area (Table 4) were several times below those calculated for onion, common garlic and leak plants cultivated in unsafe situations, e.g., using untreated contaminated waters or in the surroundings of polluted cities [17; 40; 41], and comparable with those calculated for these plant species sold in the market [42].