Spatiotemporal distribution of potentially toxic elements in the lower Gangetic delta and their implications for non-carcinogenic health risk management

River Hooghly, an offshoot of river Ganges is one of the major rivers of Asia having traditional, social, economic, religious and spiritual values. Water samples were collected from eighteen sampling locations of river Hooghly during summer, monsoon, and winter season, and analysed for basic physico-chemical properties and selected potentially toxic elements (PTEs). Several PTEs such as Al, Fe, Ni and Pb were above the permissible limits, prescribed by national and international guidelines. The trend of variation in the mean PTE concentrations showed the following order: Cd < Pb < Co < Cr < Ni < Cu < Zn < Mn < Fe. Due to the presence of high total dissolve solid (TDS) and PTE contents, the water quality of river Hooghly is not suitable for direct human consumption. The evaluated Water Quality Index (WQI) value showed a distinct spatio-temporal variation indicating very severe condition of water quality, which is deteriorating gradually from upstream to downstream. In summer, monsoon and winter, the highest WQI values were observed in Maushuni Island (S15), Petuaghat (S18) and Tapoban (S17) respectively. However, the non-carcinogenic human health risk in terms of Hazard Quotient and Hazard Index values of PTEs indicates no immediate adverse impact on human health due to exposure of PTE contaminated water from river Hooghly through ingestion or dermal route. Though these risk values for children were higher than adults warranting the adoption of a long-term management plan to cope with potential human health risks. The result suggests implementation of a combination of stringent socio-legal regulations and software based models for sustainable water related health risk management in river Hooghly.