Assessing heavy metal index referencing health risk in Ganga River System

Abstract

ABSTRACT River Ganga, one of the largest perennial rivers, conserves the cultural heritage of the Indian sub-continent, supporting as the nectar of life to millions residing on the banks of the river basin. With unlimited use, the river also receives a large amount of untreated wastewater discharged from different industrial, commercial and residential complexes, unbalancing the nutrient concentration at many points along the stretch. The current study assesses water samples collected from 20 monitoring locations and the Ganga River System in the Himalayan region, evaluating the potential risk of heavy metal pollution. The concentration of Zn, Pb, Mn, Fe, Cu, Al, Ni, Cd, Mg and Co is determined by atomic absorption spectrophotometer (AAS). Fe, Cd and Mg’s observed values exceeded various standards (WHO, BIS and USEPA) for drinking water. The pollution assessment index (heavy metal pollution index: HPI) and multivariate analysis (principal component analysis: PCA and cluster analysis: CA) were implemented to identify the intensity of pollution and its sources. The seasonal values of HPI were found 88.69, 90.32, 88.53 and 84.96 in winter, summer, monsoon and post-monsoon seasons. The index value on all monitoring locations varied between the range of PCA outcomes for three factors and explained 72.1% of the variance, indicating natural and man-made activities as responsible metal abundance factors in the river system. The hazard quotient (HQ) and hazard index (HI) are used to assess non-cancer health risks to humans. The seasonal evaluation recorded HQ < 1 for all the metals and HI > 1 was found for the entire study period. This study contributes to various conservation initiatives for the River Ganga System with factual datasets and characterization of various sampling locations using heavy metal indexing while sharing common masses’ findings for people participation at the regional level.