## 3 Results and Discussion
### Analysis and Indices Evaluation  
Eco-environment and human health risks are being examined by heavy metal pollution index methods. These indices like DC, CF, EF, Igeo, PCI, PERI, and PLI play a vital role in knowing the overall risk with respect to individual heavy metals. The descriptive statistics (mean \(\pm\) SD) of soil elemental concentration for different altitudes and background concentrations (BCs) of elements are shown in Table 1. Eco-environmental indices with estimated contamination levels in the studied region are provided in Table 4 and a further ecological risk index (Table 5) has been also evaluated. Table 1 reveals that the elevated concentration of Cu, Cr, Rb, and Zn is chiefly accountable for the soil pollution by an excess amount of heavy metals in the studied region of Uttarakhand Himalaya. The other elements such as Ca and S significantly contribute to soil contamination in some samples. The Al, Ca, Si, Mg, and Na were found to be less than their BC value. Moreover, Cu, Cr, Rb, and Zn were estimated to be more than their BC value. The maximum and mean values of Fe, Ni, and P were estimated at more than their BC value. The higher concentration of elements is an indication of the presence of contamination in the studied catchments and further risk to ecological life; contamination levels were classified based on the calculated values of the indices (DC, CF, EF, Igeo, PCI, PERI, and PLI). Further, a comparative analysis was done with an average estimated concentration of elements like Cr, Cu, Ni, Sr, and Zn with their threshold concentration in the soil sample of 100, 30, 80, 200, and 300 mg/kg, respectively [58; 86; 87]. The estimated average concentration of Cr and Cu was found higher than their corresponding threshold limit; however, Zn was found within its threshold limit. Moreover, mean concentrations of Sr and Ni were estimated more than their respective threshold limit. Geological indices like Igeo were estimated for individual elements as per the respective BC. The results reveal that the mean Igeo for elements such as Al, Ca, K, Mg, Na, P, S, and Si were found as Igeo \(\leq\) 0, indicating noncontamination of the studied catchment, which signifies no contamination with these elements, whereas elements like Cr, Cu, Fe, Mn, Ni, Rb, and Sr fall under moderately contaminated (0 \(<\) Igeo \(\leq\) 1) and/or tends toward moderately contaminated (1 \(<\) Igeo \(\leq\) 2) except Zn (which tends toward high contamination, i.e., 2 \(<\) Igeo \(\leq\) 3). Overall, the Igeo analysis reveals that Ni and Rb to some extent, and Cu, Mn, and Cr have a considerable impact on ecological life and further risk to the health of the native population of the studied region of Uttarakhand Himalaya if these elements come into the food chain. Therefore, regular monitoring of these metals in soils, food products, and vegetables are important to understand the potential health risk and further prevent accumulation of toxic metals in the food chain. Similarly, the EF of each element for the entire study was calculated and normalized against aluminum (Al) to a conservative geogenic element. The mean EF of elements Ca, Mg, Na, and Sr was estimated as 0.42, 0.68, 0.10, and 0.10, respectively, and no enrichment was found of these elements in the studied catchment, whereas Rb, Cu, Ni, and Cr fall under reasonably high enrichment (Rb \(>\) Cu \(>\) Ni \(>\) Cr). Al, Fe, K, Mn, P, S, and Zn that fall into the slight enrichment range (1 \(<\) EF \(<\) 3) might be an indication of the anthropogenic hindrance (e.g., construction of dams and roads) in the vicinity of the studied catchment. The CF of each element was calculated, and the result reveals that Na, Mg, Si, Al, K, S, Sr, and Ca were found to be less than one (i.e., CF \(<\) 1), indicating no contamination in the soil of the studied