## Materials and Methods
### Risk Analysis  
Risk analysis was performed following the deterministic approach described both by ASTM standards [46] and United States Environmental Protection Agency (US EPA) guidelines [47; 48; 49] using Risk-net software (version 3.1.1 pro; [[http://www.reconnet.net/Software.htm](http://www.reconnet.net/Software.htm)]([http://www.reconnet.net/Software.htm](http://www.reconnet.net/Software.htm)); accessed on 26 March 2023). The selected exposure routes were surface soil ingestion, dermal contact and soil dust inhalation. In addition, the risk of chronic exposure of the local population to potentially harmful arsenic levels through the consumption of vegetables was assessed, considering the most commonly used vegetables, i.e., tomatoes and black cabbage. Human receptors were both adults and children. Contaminated groundwater is not used for drinking purposes, and therefore it was not included in the risk analysis. The risk for both non-carcinogenic (Hazard Quozient--HQ) and carcinogenic (R) chronic effects in humans was calculated for each exposure pathway. The chronic daily intake (CDI, mg/kg/day) represents the exposure to a toxic agent, averaged over a long period of time, through ingestion (CDI\({}_{\text{ing}}\)) or dermal contact (CDI\({}_{\text{derm}}\)), given by:  
\[\text{CDI}_{\text{ing}}=\text{C}_{\text{POE}}\times\frac{\text{R}_{\text{ing}} \times\text{EF}\times\text{ED}\ \times\text{RBA}}{\text{BW}\times\text{AT}}\times 10^{-6}\]  
\[\text{CDI}_{\text{derm}}=\text{C}_{\text{POE}}\times\frac{\text{SA}\times \text{SAF}\times\text{ABS}\times\text{EF}\times\text{ED}}{\text{BW}\times \text{AT}}\times 10^{-6}\]  
where C\({}_{\text{POE}}\) is the exposure point concentration of the contaminant in soil (mg/kg), equal to the concentration at the source (Cs) in the case of direct exposure pathways. For the remaining parameters, recommended values [50; 51] were used: R\({}_{\text{ing}}\) is the ingestion rate (100 mg/day for adult, 200 mg/day for children), EF is the exposure frequency (350 day/year, a value suitable for a residential setting), ED is the exposure duration (24 years for adults, 6 years for children), RBA is the relative bioavailability factor (chemicalspecific, unitless, set at 0.6 for As), SA is the exposed skin area (5700 cm\({}^{2}\) for adults, 2800 cm\({}^{2}\) for children), SAF is the skin adherence factor (0.07 mg/cm\({}^{2}\) day for adults, 0.2 mg/cm\({}^{2}\) day for children), ABS is the dermal absorption factor (chemical-specific, unitless, 0.003 for As), BW is the average body weight (70 kg for adults, 15 kg for children) and AT is the average time of exposure (ED \(\times\) 365 day/year for non-carcinogens, 70 year \(\times\) 365 day/year for carcinogens). In the specific case of vegetable ingestion, C\({}_{\text{POE}}\) is the metal content in the vegetable (mg/kg, fresh weight, and RBA is set equal to 1). The Ingestion Rate (R\({}_{\text{ing}}\) = 76 gr/day for tomato and 2.5 gr/day for black cabbage) was taken from the most recent Italian food consumption survey, and it is relative to the individual daily consumption of both fresh and processed tomatoes referred to the total sample of the Italian population considered by the INRAN-SCAI 2005-2006 survey [52].