## 2 Materials and Methods
### Assessment of HM Contamination, Ecological and Health Hazards
The non-carcinogenic exposure doses through ingestion, dermal absorption, and inhalation were calculated using Equations (5)-(7):  
\[\text{ED}_{\text{ing-nc}}=\frac{\text{C}\times\text{IngR}\times\text{ED} \times\text{EF}\times\text{CF}}{\text{BW}\times\text{AT}_{\text{nc}}}, \tag{5}\]  
\[\text{ED}_{\text{derm-nc}}=\frac{\text{C}\times\text{ABS}\times\text{AF} \times\text{ED}\times\text{EF}\times\text{SA}\times\text{CF}}{\text{BW}\times \text{AT}_{\text{nc}}}, \tag{6}\]  
\[\text{ED}_{\text{inh-nc}}=\frac{\text{C}\times\text{ET}\times\text{ED}\times \text{EF}}{\text{PEF}\times 24\times\text{AT}_{\text{nc}}}, \tag{7}\]  
where C is measured HM concentration (mg kg\({}^{-1}\)), IngR is the soil ingestion rate for the receptor (mg day\({}^{-1}\)), CF is the unit conversion factor (kg mg\({}^{-1}\)), ED is the exposure duration (year), EF is the exposure frequency (day year\({}^{-1}\)), ABS is the dermal absorption factor (unit less), AF is the soil to skin adherence factor (mg cm\({}^{-2}\)), SA is the skin surface area available for exposure (cm\({}^{2}\)), ET is the exposure time (h day\({}^{-1}\)), BW is the average body weight (kg), AT\({}_{\text{nc}}\) is the averaging time for non-carcinogens (day), and PEF is the soil-to-air particulate emission factor (m\({}^{3}\) kg\({}^{-1}\)). The non-carcinogenic hazard quotient of a single HM was calculated using Equation (8):  
\[\text{HQ}_{\text{ing/derm/inh}}=\frac{\text{ED}_{\text{ing/derm/inh-nc}}}{\text {RfD}_{\text{ing/derm/inh}}}, \tag{8}\]  
where RfD\({}_{\text{ing/derm/inh}}\) is the non-carcinogenic reference dose (mg kg\({}^{-1}\) day\({}^{-1}\)) through oral ingestion, dermal absorption, and inhalation. RfD\({}_{\text{ing}}\) values for As, Cu, Mo, and Zn were derived from the USEPA (2003) [21] and the RfD\({}_{\text{derm}}\) values for these elements were obtained from the RfD\({}_{\text{ing}}\) values by their conversion based on oral absorption efficiency for dermal absorption derived from the USEPA (2004) [22]. RfD\({}_{\text{ing}}\) and RfD\({}_{\text{derm}}\) values for Pb were derived from [23]. HQ\({}_{\text{inh}}\) was calculated for As only, the RfD\({}_{\text{inh}}\) value for which was derived from the Agency for Toxic Substances and Disease Registry (ATSDR-2007) [24]. The single metal non-carcinogenic hazard index via ingestion, dermal, and inhalation contact with soil was calculated using Equation (9):  
\[\text{HI}_{\text{nc}}=\sum\text{HQ}=\text{HQ}_{\text{ing}}+\text{HQ}_{\text{ derm}}+\text{HQ}_{\text{inh}}. \tag{9}\]  
Non-carcinogenic health risks posed by all metals, expressed as the overall hazard index (OHI), were assessed by the following equation:  
\[\text{OHI}_{\text{nc}}=\sum_{\text{i}=0}^{\text{n}}\text{HI}_{\text{nc}}. \tag{10}\]  
The carcinogenic exposure doses for only As and Pb were used to assess carcinogenic health risks. The exposure doses through ingestion, dermal absorption, and inhalation were calculated using Equations (11)-(15):  
\[\text{C}_{\text{r}}^{\text{i}}=\frac{\text{C}_{\text{s}}^{\text{i}}}{\text{C} _{\text{n}}^{\text{i}}}, \tag{2}\]0  
\[\text{C}_{\text{r}}^{\text{i}}=\frac{\text{C}_{\text{s}}^{\text{i}}}{\text{C} _{\text{n}}^{\text{i}}}, \tag{2}\]1  
\[\text{C}_{\text{r}}^{\text{i}}=\frac{\text{C}_{\text{s}}^{\text{i}}}{\text{C} _{\text{n}}^{\text{i}}}, \tag{2}\]2  
\[\text{C}_{\text{r}}^{\text{i}}=\frac{\text{C}_{\text{s}}^{\text{i}}}{\text{C} _{\text{n}}^{\text{i}}}, \tag{2}\]3  
\[\text{C}_{\text{r}}^{\text{i}}=\frac{\text{C}_{\text{s}}^{\text{i}}}{\text{C} _{\text{n}}^{\text{i}}}, \tag{2}\]4  
where IR is soil ingestion rate-age adjusted (mg year kg\({}^{-1}\) day\({}^{-1}\)), DFS is soil dermal contact factor-age adjusted (mg year kg\({}^{-1}\) day\({}^{-1}\)), and ATca is averaging time for carcinogens (day).