Human health hazard evaluation with reference to chromium (Cr+3 and Cr+6) in groundwater of Bengaluru Metropolitan City, South India

Discharges from industries have caused groundwater contamination in one of the largest industrial sectors (i.e., Bengaluru) Karnataka State, Southern India. This study evaluated the quality of groundwater samples collected during July 2016, January 2017, and August 2017 respectively. The samples were analyzed for heavy metals. The health hazard model was added to evaluate the human health hazard concerning chromium concentrations caused by liquefied pollution in groundwater. Results were compared with WHO standards, the exceeding rates (> 0.05 mg/L) of trivalent chromium (Cr+3); 35.38% (July 2016), 32.39% (January 2017), and 39.43% (August 2017) and hexavalent chromium (Cr+6); 3.07% (July 2016) and 26.76% (January 2017) found in the groundwater. Non-carcinogenic and carcinogenic risks of hazard quotient (HQ), health hazard index (HHI), cancer risk (CR), and total cancer risk (TCR) were used to assess the potential health hazard. The health risks allied with non-carcinogenic affluence through ingestion were higher than those allied with dermal contact. The non-carcinogenic risk was very high in children than that of adults, and their risk values exceeds the threshold value. TCR for Cr+3 and Cr+6 concentrations in groundwater were found higher than the threshold value of 1.00E-04, indicating significant carcinogenic threat. Principal component analyses (PCA) prevalent three to four components for identification of the sources. Total variance of 82.65%, 74.89%, and 83.17% for the three seasons indicating loading of various metals. Suitable preparation for mitigation is necessary and large-scale analysis along with the distribution of wells among neighbors is suggested for decreasing human health exposure.