Ecological and health risk assessment of different land uses along with seasonal variation in toxic metal contamination around Varanasi city situated in Indo-Gangetic Plain

摘要

Metal pollution load in soil environment has been enhanced during last few decades due to increasing industrialization and wide application of metals in all sectors. Due to the persistent and hazardous nature of metals, it can accumulate in the living system and cause severe risks to the ecosystem. The abundance of metals in soils from 5 different land use systems (industrial, industrial highway, brick kiln production area, residential highways and botanical gardens) in the Indo-Gangetic Plain region of India was analysed for three consecutive years (2018-2020) to evaluate the effects of metal load on soil properties and ecosystem health. Soil enzymatic activities, moisture, porosity, total nitrogen, and organic carbon were least at the industrial area of Ramnagar site and highest at Botanical garden area of BHU. Geochemical indices were calculated to compare the background status of metals in the soil where Cd, Cu, Cr, Co, Ni, Mn and Zn were increased in recent times. Contamination, enrichment and potential ecological risk factors with respect to Cu and Cd contents in soil were significantly higher at industrial area of Ramnagar and highway near industrial area. Maximum lifetime non-cancer and cancer health hazards were observed for Cd and Ni, respectively. The study clearly indicates that Cd, Cu and Ni are capable of posing health risk and cause imbalance in ecological functioning of soil due to chronic exposure of the potential toxic metals generated through change in land uses in suburban areas of Indo-Gangetic Plain region.