Evaluation of heavy metal and microbial contamination in various water resources of West and North Sikkim, India

Abstract The present study investigates coliform bacteria contaminations and heavy metal pollution vulnerability of springs, rivers, and household water samples in the climatically and lithologically distinct segments of the Sikkim Himalaya. A total of 42 samples were collected from West and North d...
Ausführliche Beschreibung

Abstract The present study investigates coliform bacteria contaminations and heavy metal pollution vulnerability of springs, rivers, and household water samples in the climatically and lithologically distinct segments of the Sikkim Himalaya. A total of 42 samples were collected from West and North districts of Sikkim during the wet and dry seasons. The integrated approach applied in this study includes pollution evaluation indices and multivariate statistical analysis to evaluate the intensity and source of pollution. The average concentrations of trace elements in the wet season in the order of their concentration are U < As < Li < Cu < Ba < Mn < Al < Zn < Fe and in the dry season are As < U < Li < Cu < Mn < Ba < Zn < Al < Fe, respectively. The distribution map of pollution evaluation indices, total coliform bacteria (TC), thermotolerant coliforms (TTC), and Escherichia coli (E. coli) indicate a significant spatial and temporal variation. Further, it is observed that 100% and 67% of the water samples were contaminated with E. coli in the wet and dry seasons, respectively. The multivariate statistical techniques suggest that geogenic sources and anthropogenic activities via the municipal sewage systems have assimilated various contaminants which account for the concentration of heavy metals. The current distribution level of TC, TTC, E. coli, and trace elements such as Al, Fe, and Zn is of environmental and health concern which requires attention. It indicates that the region’s most dependable springs and stream water used for consumption are susceptible to contamination and therefore need treatment before consumption. Ausführliche Beschreibung