An Overview of Metal(oid) Pollution, Sources, and Probabilistic Health Risk Evaluations Based on a Monte Carlo Simulation of Surface River Water in a Developing Country

Water pollution is a significant problem stemming from several causes, with the contamination of heavy metal(oid)s being a primary concern. This is especially concerning because of the poisonous characteristics of these metal(oid)s and their effects on the aquatic ecosystem. This research is distinguished by its unique methodology for assessing metal(oid)s in the surface water of Bangladeshi rivers over a period of sixteen years, from 2007 to 2022. This work seeks to elucidate recent results on metal(oid) concentrations, contamination levels, multivariate statistical analyses, source identification using positive matrix factorization models, and probabilistic health risks. The findings reveal that the concentrations of chromium, nickel, arsenic, cadmium, and lead exceeded the acceptable limits for drinking water established by the World Health Organization (WHO) by factors of 4.64, 2.25, 22.51, 45.60, and 10.13, respectively. Our meta-analysis, subsequent to a Principal Component Analysis, indicated that increased concentrations of hazardous metals account for 85.47% of the variation from both anthropogenic and natural causes. Ecological risk indicators, including the metal index (84.06) and the Nemerow pollution index (10.55), indicated significant metal contamination. Ecological risk indicators, like the metal index (84.06) and the Nemerow pollution index (10.55), indicate substantial metal contamination. The positive matrix factorization (PMF) model detected the following sources of metals in water: industrial (22%), mixed (32%), agricultural activities (27%), and natural sources (19%). Furthermore, Monte Carlo-simulation-based assessments of health hazards indicated that the mean hazard index (HI) and cancer risk values for adults (301.89 and 422.76) and children (51.56 and 39.45) significantly exceeded the recommended limits, suggesting that both adults and children are vulnerable to potential non-carcinogenic and carcinogenic health risks. The immediate execution of control measures and regulations is essential to avert escalating pollution in surface water, protect ecosystems, and mitigate health hazards.