Health Risks Assessment of Heavy Metal Contamination in Drinking Water Collected from Different Educational Institutions of Khulna City Corporation, Bangladesh

Clean and safe drinking water is indispensable for maintaining the sound health of humans. The presence of toxic elements in drinking water may cause several health effects. In this study, the concentrations of heavy metals in the drinking water of different academic institutions of Khulna city corporation (KCC) were determined using an atomic absorption spectrophotometer (AAS) and the human health risks were assessed based on estimated daily intake (EDI), target hazard quotient (THQ), hazardous index (HI) and target cancer risks (TCR). The range of the investigated heavy metals was as follows: Fe (18.5−861.6 µg/L), Mn (0.020−0.564 µg/L), Zn (8.8−96.1 µg/L), Cu (5.6−52.9 µg/L), and As (<0.5−105.3 µg/L). About 52% of the drinking water samples for Mn and 12% samples for As surpassed the Bangladesh standard (BDS) value of 50.0 µg/L. On the other hand, As concentration in 88% of samples exceeded the guideline value of the World Health Organization (WHO) (10.0 µg/L). Analysis of Pearson’s correlation matrix (r) showed a positive correlation between Zn−Mn, Cu−Mn, Zn−Fe, Cu−Fe, and Fe−Mn at 0.01 level; and Zn−Cu and Fe−As at 0.05 level, indicating the same pollution source. However, the THQ values of Zn, Cu, Fe, and Mn in all the studied samples were within the threshold risk limit (THQ < 1.0), hence safe from metal toxicity. But, THQ and HI of As for both adults and children; and TCR of As for adults in most of the investigated samples exceeded the maximum risk limit (THQ < 1.0; HI < 1.0; and TCR = 10−4), which revealed As could be a potential source of carcinogenic and non-carcinogenic health risks. Therefore, regular monitoring of heavy metals should be carried out to assure good quality drinking water for the students and academic staff.