Trace metals induce microbial risk and antimicrobial resistance in biofilm in drinking water

This study investigated the changes in water quality and microbial risks resulting from trace metal pollutants in stagnant drinking water conditions using a 168-h experimental simulation and a metagenomic approach. The results showed that Fe(III) increased the water turbidity. Stagnation also caused significant biofilm growth, which was increased by trace metal pollutants, resulting in a higher production of extracellular polymeric substances (EPS). Adaptive mechanisms of bacterial communities dominated by Pseudomonadota in response to trace metal pollutant stress were discovered. Pathogenic bacteria, particularly Salmonella enterica and Pseudomonas aeruginosa, were found in stagnant drinking water, potentially exacerbated by Al(III). The overall exposure risk of antibiotic resistance genes (ARGs) increased, whereas Fe(III) enhanced the co-occurrence of ARGs and pathogens, potentially leading to serious hidden microbial risks. This study reveals imperceptible microbial risks posed by trace metal pollutants in stagnant drinking water, providing scientific warning and advice for drinking water safety.