Spatio-temporal variations of metals in groundwater from an iron mining impacted area: Assessing sources and human health risk

The concentrations of metals were determined seasonally to assess the probable risk on the local population due to ingestion of metals via the groundwater in an iron mining impacted area of Jharkhand in India. The results depicted significant spatial and temporal variation in the concentration of metals with the highest values during the pre-monsoon season and in the locations with active mining activities. Fe and Mn exceeded the drinking water quality standards in about 75% of the samples considering all the seasons. The metals in the groundwater can be ascribed to both geogenic sources and anthropogenic causes as depicted from principal component analysis, which resulted in extraction of four factors explaining 68.1% of data variance. The hazard quotients (HQ) of the metals calculated for the human health risk assessment according to USEPA methodology suggested that the metals individually did not pose risk to the local population since the HQ of the metals did not exceed unity. However, collective risk of the metals as calculated by the Hazard Index (HI) suggested that the groundwater of most of the locations is unfit for drinking predominantly in the pre monsoon season. The child residents were more susceptible to non-carcinogenic risk than the adult population. The HI for the child population was estimated to be greater than one (1.16) in the pre monsoon season suggesting health risk for vulnerable child populace. The risk was higher in the pre monsoon season as compared to other seasons.