## 3 Results and Discussion  
### Characterization and Distribution of Metal(loid)s in Soil  
In general, the soil was strongly alkaline (the average pH was 8.30), and the pH of the soil ranged from 7.43 to 9.05. The median total organic matter (TOC) content was 1.04% and ranged from 0.31% to 2.67%. The soils had moderate cation exchange capacities (CeC) (mean 11.07 cmol/kg) that ranged between 3.76 and 24.20 cmol/kg. Clay content ranged from 16.0 to 265.2 g/kg, with a mean value of 98.1 g/kg (Figure 2). The concentrations of eight metal(loid)s in the soil are given, along with the permissible amounts according to the Chinese standards, in Table 1. The standard values for the different metal(loid)s are the most recent ones published by the Environmental Protection Administration of the PRC to assist with protecting the soil environment and agricultural production [49]. The results of agricultural soil Cu, Pb, Zn, Cr, Ni, Cd, As, and Hg contents averaged 25.72, 24.76, 78.47, 67.74, 28.84, 0.20, 9.89, and 0.06 mg/kg, respectively. Most of these values are below the soil environmental quality risk control standard for soil contamination of agricultural land (GB15618-2018) (based on different pH) safety limits [51]. However, Cu and As each had one sample that exceeded the safety limit value. Compared with the background values, most metal(loid)s exceeded the local background values. The mean value of Cd was more than double the local background value [51] and had a coefficient of variation of 1.9, indicating that it was greatly affected by exogenous factors. Only Ni and As had values below the background values. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**mg/kg**} & \multirow{2}{*}{**Mean**} & **Coefficient of** & **Food** & **Local** & **Soil** \\  & & **Variable (CV), \%** & **Threshold [50]** & **Background** & **Environmental** \\  & & & **Values [51]** & **Quality [49]** \\ \hline Cu corn & 1.40 & 26.75 & & & \\ Cu wheat & 4.63 & 21.21 & & & \\ Cu soil & 25.72 & 58.50 & & 21.8 & 100 \\ Pb\({}^{2}\) corn & 0.05 & 71.83 & 0.20 & & \\ Pb\({}^{3}\) wheat & 0.06 & 59.07 & & & \\ Pb soil & 24.76 & 39.25 & & 21.5 & 170 \\ Zn corn & 21.46 & 17.43 & - & & \\ Zn wheat & 32.07 & 23.08 & & & \\ Zn soil & 78.47 & 74.47 & & 71.9 & 300 \\ Cr corn & 0.03 & 68.64 & 1.00 & & \\ Cr wheat & 0.03 & 35.26 & & & \\ Cr soil & 67.74 & 10.84 & & 68.3 & 250 \\ Ni corn & 0.22 & 29.52 & & 1.00 & \\ Ni wheat & 0.10 & 48.04 & & & \\ Ni soil & 28.84 & 17.20 & & 30.8 & 190 \\ Cd corn & 0.0043 & 79.70 & 0.10 & & \\ Cd\({}^{3}\) wheat & 0.03 & 50.71 & & & \\ Cd soil & 0.20 & 191.69 & & 0.09 & 0.6 \\ As corn & 0.01 & 68.35 & 0.50 & & \\ As wheat & 0.03 & 76.41 & & & \\ As soil & 9.89 & 30.73 & & 12.8 & 25 \\ Hg\({}^{2}\) corn & 0.0040 & 92.39 & & & \\ Hg\({}^{1}\) wheat & 0.002 & 82.54 & 0.02 & & \\ Hg soil & 0.06 & 62.78 & & 0.04 & 3.4 \\ \hline \hline \end{tabular}  
* Pb\({}^{2}\) corn, Cd\({}^{3}\) wheat, Hg\({}^{2}\) corn, and Hg\({}^{1}\) wheat represent crops that exceed the guidelines for soil food quality (GB2762-2012) [50].  
\end{table} 
Table 1: Comprehensive statistical analysis for wheat, corn, and soil. The Igeo values of the agricultural soil from the study area decreased in the following order: Cd Hg \(>\) Cu \(>\) Pb \(>\) Zn \(>\) Ni \(>\) Cr \(>\) As. These values ranged from \(-\)0.293 to 1.438 (average 0.008) for Cd, \(-\)0.499 to 0.777 (average: \(-\)0.048) for Hg, \(-\)0.372 to 0.845 (average: \(-\)0.127) for Cu, \(-\)0.318 to 0.585 (average: \(-\)0.134) for Pb, \(-\)0.402 to 0.911 (average: \(-\)0.165) for Zn, \(-\)0.439 to \(-\)0.029 (average: \(-\)0.211) for Ni, \(-\)0.336 to \(-\)0.072 (average: \(-\)0.182) for Cr, and \(-\)0.891 to 0.187 (average: \(-\)0.309) for As (Figure 2).