## 3 Results and Discussion
### Analysis and Indices Evaluation
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**S. No** & **Elements** & **Potential Ecological Risk Factor (Pn)** & **Ecological Risk** \\ \hline
1. & Cr & 10.69 & Low \\
2. & Mn & 2.17 & Low \\
3. & Ni & 28.38 & Low \\
4. & Cu & 31.95 & Low \\
5. & Zn & 2.37 & Low \\ \hline \multicolumn{3}{c}{Net PERI} & 75.56 & Low \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Calculated potential ecological risk index. Himalayas catchment, while P, Mn, Fe, and Zn showed reasonable contamination (1 \(<\) CF \(>\) 3) in the studied samples. These elements are generally present in the natural ecosystem and also added to the food producing system as fertilizers, etc., and are beneficial for the growth and development at tracer levels [88]. Different species including humans in healthy conditions have been reported to have the intrinsic capacity to remove the excess elements without much damage. However, continuous exposure to certain elements either through occupation or through contaminated intake along with food, certain medical conditions, impairment of biochemical processes, and accidental intake could be problematic [3; 89]. For example, neurotoxicity due to inhalation exposure to airborne Mn has been reported [24; 90; 91]. Fe toxicity has long been already established by [PERSON] et al. [92]. The Zn is an essential element for many biochemically important enzymes in plants as well as animal systems. The permission limit of Zn in Indian soil is 600 ug/g [93]. Over the permissible limits of these elements, they can be problematic/toxic to the living system through impairment of the various physiological, biochemical, growth, and development processes [3; 94; 95]. Moreover, Cr, Cu, Ni, and Rb fall under considerable contamination to high contamination levels, following the order Rb \(>\) Cu \(>\) Ni \(>\) Cr. Heavy metal toxicity involves oxidative and genotoxic mechanisms [96]. When the direct exposure of toxic elements is not present, these elements can have poisonous effects on the population of a particular region due to accumulation in the food chain [97]. The rubidium (Rb) is observed to be moderately toxic to human as it mimics potassium [26]. Further, PLI was calculated by the conversion factors of each element, and the estimated PLI was found to be 1.26, indicating the presence of pollution in the studied catchment. Calculated PLI results were verified by the degree of contamination (DC) index (Table 4), with results showing a high degree of pollution (DC: 36.66; i.e., DC \(>\) 32) at the study site. This high value of DC is due to high anthropogenic activity in the studied catchment. The potential of contamination was calculated using PCI and the results reveal that the studied catchment has low contamination of Na and Si and reasonable contamination of Mg, Al, S, K, Ca, and Sr, whereas other parameters fall between severe to very severe contamination and follow the order Rb \(>\) Cu \(>\) Mn \(>\) Zn \(>\) P \(>\) Fe. After ascertaining the pollution contamination in the studied catchment, PERI was calculated (using CF and Tn values) to determine the potential ecological risk in the studied catchment (Table 5). The Pn of each element (Cr, Mn, Ni, Cu, Zn) was \(<\)40, where PERI was calculated as 75.56, indicating low ecological risk where Ni and Cu contribute a greater share compared to Cr, Mn, and Zn.