Spatial variations in metals of groundwater in Naini industrial area: assessing probable sources and human health risk

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ABSTRACT Groundwater forms the major source of drinking water worldwide; however, its quality has been compromised due to various human activities. The contamination of groundwater with metals have increased the health risk of the consumers. In pursuit of risk assessment and source apportionment studies of groundwater of Naini Industrial Area, Prayagraj, Uttar Pradesh, India; groundwater samples (n = 60) were collected from distinct sampling locations spanning the study area. Inductively coupled plasma-mass spectrometry (ICP-MS) was employed to analyse the concentrations of Aluminium (Al), Arsenic (As), Barium (Ba), Cadmium (Cd), Chromium (Cr), Cobalt (Co), Copper (Cu), Iron (Fe), Manganese (Mn), Nickel (Ni), Lead (Pb), Selenium (Se), Strontium (Sr), Vanadium (V) and Zinc (Zn). Amongst all the metals analysed, Al and Fe surpassed drinking water standards in more than 50% of the samples. Principal component analysis (PCA) extracted four factors that collectively accounted for 76.3% of the variability in the data. As illustrated by PCA, metals in the groundwater can be attributed to geological origins combined with anthropogenic contributions. Considering the central tendency of the metals, the non-cancer risk as per United States Environmental Protection Agency (USEPA) methodology depicted by Hazard Quotient (HQ) of the metals did not exceed unity and can be inferred that they did not pose risk to the human health individually. However, the combined risk of the metals as depicted by Hazard Index (HI) suggested considerable hazard to the child residents with HI value of 1.27. Across all the sampled sites, the HI values varied from 0.48 to 4.07 for males, 0.41 to 3.51 for females, and 0.76 to 6.51 for children. Considering central tendency, carcinogenic risk associated with As and Cr was determined to be within the tolerable cancer risk value of 1 × 10−4. Nevertheless, the cancer risk for the groundwater surpassed the acceptable limit in few of the locations rendering them unsuitable for drinking without treatment.