Comparative assessment of heavy metals in potable drinking water sources in Bhojpur, Bihar

Abstract

Chronic arsenic endosmosis causes severe threat to human health within the developing countries. This study assessed the levels of geogenicarsenic and other heavy metals as well as the controlling factors of arsenic release in the aquifers within the drinking water sources in the middle Gangetic plains of Bhojpur district in Bihar, India. Six water samples were collected from hand-dug wells within the six severely arsenic contaminated regions namely Bakhorapur, Cheenegaon, Gajiapur, Cheenegaon Tola, Dubechappra and Alekh Tolain the Bhojpur district.The levels of arsenic (As), nickel (Ni),cadmium (Cd), zinc (Zn), cobalt (Co)and lead (Pb), were determined using an inductively coupled plasma-atomic absorption spectrophotometer (ICP- AAS). The As concentration ranged from0.06-4.76 mg/l within the samples,above a prescribed guideline of 0.01 mg/l for drinking water by WHO. The mean level of other heavy metals were <0.02 (Ni), <0.001 (Cd), <0.11 (Zn), <0.5 (Co) and <0.04 (Pb). The presence of high NO3-ions within the region indicates a significant correlation with arsenic, attributing to the high usage of phosphate fertilizers, incrementing the concentration of arsenic within the shallow aquifers. Intensive use of agrochemicals and anthropogenic activities also results in the high occurrence of arsenic. Decoupling of HCO3-and arsenic at an elevated pH, and competitive ion-exchange process also plays a vital role in arsenic mobilization to aquifer systems. Continuous monitoring of the drinking water sources to maintain the quality is highly recommended to prevent any further health risks.