Source apportionment and human health risk assessment of heavy metal(loid)s in drinking water of medical centers in Khulna, Bangladesh

Ensuring safe and reliable drinking water in healthcare facilities is essential for protecting vulnerable patients; however, maintaining acceptable water quality remains a major challenge in developing countries. This study evaluated heavy metal(loid) contamination in hospital drinking water in Khulna, Bangladesh, identified potential contamination sources, and assessed associated human health risks. Sixty drinking water samples were collected from randomly selected healthcare centers and analyzed for Fe, Cr, As, Pb, Cd, Zn, and Cu using AAS and hydride generation AAS (HG-AAS). Mean concentrations (mg/L) of Fe, Cr, As, Pb, Cd, Zn, and Cu were 0.0174, 0.0139, 0.0013, 0.0243, 0.0038, 0.0009, and 0.0112, respectively, with a substantial proportion of samples exceeding WHO guideline values. Principal Component Analysis and Cluster Analysis indicated that Fe, Zn, Cr, and Cu mainly originated from geogenic processes and pipe corrosion, whereas Pb and As were linked to aging distribution systems and groundwater, while Cd reflected localized anthropogenic contamination. The Heavy Metal Pollution Index classified approximately 83.34% of samples as highly polluted, whereas the Heavy Metal Evaluation Index identified about 28.33% as suitable for use, highlighting contrasting assessments of water quality. The Nemerow Index indicated contamination levels ranging from unpolluted to moderately polluted. Monte Carlo simulation showed that the mean non-carcinogenic hazard indices (HI) for adults (2.1) and children (1.7) exceeded the acceptable threshold of 1, with substantial portions of the simulated distributions also exceeding this benchmark. Total carcinogenic risks likewise exceeded conventional acceptable-risk ranges. These findings highlight the urgent need for effective water treatment, routine monitoring, and improved management of hospital drinking water systems to minimize carcinogenic health risks.