2023 Volume 46 Issue 5 Pages 113-122
We investigated the microbial contamination in various swimming pools in elementary schools and sporting facilities under normal conditions without a reported outbreak of pathogens. We further elucidated their contamination factors according to usage and water quality control practice and evaluated the effectiveness of various bacteria and viruses as indicators of fecal contamination in those waters. The results showed that the detection of microorganisms varied depending on usage conditions, water quality control practice, and facility characteristics (e.g. outdoors or indoors) . Both Escherichia coli and F-specific bacteriophages were detected by culture methods, suggesting that their complete inactivation is difficult with current water quality control practices. Novel contamination indicators, such as the pepper mild mottle virus, cross-assembly phage, and human-specific HF183 Bacteroides 16S rRNA gene marker, were detected at relatively high frequencies. In particular, the cross-assembly phage and HF183 were considered as effective indicators of human fecal contamination in swimming pools where water quality was controlled by filtration and chlorination. Human enteric viruses were not detected in all of the surveyed swimming pools; however, when those pathogens are excreted from infected individuals to swimming pool waters, they may be present in the waters without losing infectivity.
