## 3 Results and Discussion
### Adverse Ecological and Biological Effects of HM Contamination in Soil  
The assessment of the potential ecological risks of soil contamination with single HMs showed that E\({}_{\mathrm{r}}^{\mathrm{i}}\) values for Zn and Pb at all the investigated sites, as well as As and Cu at sites S-700 and S-300-S-700, respectively, were lower than 40, indicating a low risk (Figure 3). As, Cu, and Mo contamination at sites S-200-S-300, S-50-S-200, and S-200-S-700, respectively, showed a moderate risk, while As and Mo contamination at sites S-50-S-100 indicating high and considerable risks, respectively (Figure 3), was of particularly high concern. The investigated HMs according to E\({}_{\mathrm{r}}^{\mathrm{i}}\) values can be ranked as As \(>\) Mo \(>\) Cu \(>\) Pb \(>\) Zn at sites S-50-S-100 and S-300, and Mo \(>\) As \(>\) Cu \(>\) Pb \(>\) Zn at sites S-200 and S-700 (Figure 3). As and Mo were the ecologically riskiest elements in the investigated soils; therefore, more attention should be paid to these metals to prevent potential ecotoxicity from these contaminants. Soil contamination with all the investigated HMs showed a low, moderate, and considerable risk at sites S-300-S-700, S-200, and S-50-S-100, respectively, according to the PERI values (Figure 3). The investigated sites can be ranked according to the overall potential ecological risk (PERI) in decreasing order as follows: S-100\(>\)S-50\(>\)S-200\(>\)S-300\(>\)S-700 (Figure 3). The highest overall potential ecological risk was posed by the sites closest to the smelter (S-50 and S-100). The risk noticeably decreased at site S-200 and continued to decrease with an increase in distance from the smelter (Figure 3). \begin{table}
\begin{tabular}{c c c c c c c} \hline  & **As** & **Cu** & **Zn** & **Pb** & **Mo** & **Biomass** \\ \hline
**As** & \(1\) & & & & & \\
**Cu** & \(0.703\) & \(1\) & & & & \\
**Zn** & \(0.901\) & \(0.863\) & \(1\) & & & \\
**Pb** & \(-0.574\) & \(0.159\) & \(-0.273\) & \(1\) & & \\
**Mo** & \(0.970\) & \(0.796\) & \(0.944\) & \(-0.428\) & \(1\) & \\
**Biomass** & \(-0.504\) & \(-0.948\) & \(-0.741\) & \(-0.326\) & \(-0.621\) & \(1\) \\ \hline \end{tabular}
\end{table} 
Table 2: [PERSON]’s coefficients of correlations between HMs and between HMs and invertebrate biomass. \begin{table}
\begin{tabular}{c c c c c c} \hline  & **As** & **Cu** & **Zn** & **Pb** & **Mo** \\ \hline
**S-50** & \(3.98\) & \(2.67\) & \(1.27\) & \(-0.74\) & \(2.19\) \\
**S-100** & \(3.94\) & \(2.74\) & \(1.01\) & \(-0.58\) & \(2.29\) \\
**S-200** & \(1.86\) & \(2.57\) & \(0.68\) & \(0.09\) & \(1.26\) \\
**S-300** & \(1.79\) & \(2.37\) & \(0.27\) & \(-0.10\) & \(0.58\) \\
**S-700** & \(1.27\) & \(2.04\) & \(0.45\) & \(-0.26\) & \(0.96\) \\ \hline \end{tabular}
\end{table} 
Table 3: Igeo of the investigated HMs in the soil located at different distances from the Alaverdi copper smelter. The biological analysis showed that the biomass of invertebrates occurring in the investigated soils noticeably increased with an increase in distance from the smelter (Figure 4). The biomass at the reference site was 11,886.5 mg m\({}^{-2}\), so no organisms were observed at the site closest to the smelter (S-50; Figure 4). The loss of biomass was 100, 99.83, 99.44, 97.33, and 88.20% at sites S-50, S-100, S-200, S-300, and S-700, respectively, compared to the reference site (Figure 4). The mean biomass value in the soil potentially affected by the ex-operation of the smelter (sites S-50-S700) was significantly lower (\(p<0.001\)) than the biomass registered at the reference site. Statistical analysis revealed a strong negative correlation between the biomass value and the concentration of single elements such as As, Cu, Zn, and Mo and a moderate negative correlation between the biomass value and the Pb concentration (Table 2). However, a statistically significant correlation was only observed between the biomass value and the Cu concentration (\(p<0.005\); Table 2).