Identifying drinking-water quality threats for a small town in Karnataka by geogenic and anthropogenic contaminants

Abstract

The study’s objectives are to evaluate the combined threats to the drinking-water quality of Mulbagal town from fluoride and pit toilet leachate contamination, prioritize drinking-water hazards, and provide recommendations for safe drinking water. The objectives were achieved by measuring the tube well’s inorganic and microbial water quality, statistical analysis of the data, evaluating E. coli contamination and free chlorine residual levels during transport and storage, and performing qualitative risk analysis to prioritize drinking-water hazards. The tube-well samples conformed to the acceptable (1.0 mg/L)/permissible (1.5 mg/L) fluoride limits in drinking water. Pearson correlation and hierarchical cluster analysis tools indicated that tube wells inside the town are prone to blackwater contamination. Nitrate (55 to 388 mg/L) and E. coli (2 to 1601 CFU/100 mL) contaminated eighty-four % and seventy-seven % of tube wells inside the town. Qualitative risk analysis indicated that acute and chronic ailments would most certainly impact a large town population if they were to drink tube-well water contaminated with E. coli and nitrate pollutants. Drinking tube-well water from outside the town posed an insignificant risk of nitrate contamination. Microbial contamination during water transport exposes the large population to the daily ill effects of E. coli contamination. Adequate chlorination should be performed in storage reservoirs to maintain 0.2 mg/L of free chlorine residual in the household water containers after 24 h.