Spatial distribution and health risk assessment of heavy metals in drinking water in Nikshahr and Iranshahr cities of Iran

Abstract

ABSTRACT The presence of high concentrations of certain heavy metals (HMs) in drinking water poses a serious threat to the health of consumers. This work was done to investigate the concentration of heavy metals such as Arsenic (As) cadmium (Cd), chromium (Cr), iron (Fe), mercury (Hg), nickel (Ni), lead (Pb) and cobalt (Co) in the water resources of two cities of Iranshahr and Nikshahr in the south of Sistan and Baluchistan province. For this aim, 24 samples of drinking water sources were collected and the concentration of heavy metals was determined by inductively coupled plasma-mass spectrometry (ICP-MS). The results of samples of these networks showed that the average concentration of Pb (11.25 μg/L), Hg (10.33 μg/L), As (10.62 μg/L) and Cd (3.45 μg/L) far exceeds the standard of the World Health Organisation. The average concentration of heavy metals in the drinking water of Iranshahr and Nikshahr is respectively Fe>Pb>As>Hg>Ni>Cr>Co>Cd and Fe>Pb>As> Ni > Cr >Co>Cd> Hg. Potential sources of pollution in this study are attributed to infiltration of industrial effluents and agricultural runoff, which is a significant threat to groundwater quality. The calculated hazard quotients (HQ(values for non-carcinogenic risk show that this value is less than 1 in most metals, but the hazard index)HI) in children is greater than 1, and non-carcinogenic risk is evident. HI was obtained for children 5.4 and adults 2.6. However, the risk of carcinogenics in children and adults is equal to 2.66 E-05 and1.3E–6, respectively, and the increase in the risk of cancer in children is higher due to the consumption of drinking water. Therefore, it is necessary to protect water sources, water treatment and monitor more water distribution networks based on the water safety plan.