A Citizen Science Approach for Mapping Total Microbial Communities and Waterborne Pathogens in Household Drinking Water in China

Abstract

AbstractEnsuring safe drinking water is one of the top priorities in public health as waterborne diseases remain a global challenge. In China, microbial contamination in drinking water is a particular concern and comprehensive survey/monitoring of the drinking water microbiome is necessary. However, traditional culture-based microbial monitoring methods have significant limitations, and nationwide tap water survey/monitoring in China would require significant resources. Here, a cost-effective citizen science approach was developed to collect household drinking water samples (n = 50) from 19 provinces in China during December 2020 to August 2021. Using a protocol optimized for low-biomass samples, 22 out of 50 tap water samples were tested positive for microbial DNA. The PCR products were pooled for 16S rRNA genes metabarcoding to elucidate the tap water microbiome and detect waterborne pathogens, yielding 7,635 Amplicon Sequence Variants (ASVs). Outdoor temperature was found to be the first-order driver of total microbial community structure, validating our citizen science approach against previous studies. Alarmingly, pathogenic bacteria includingMycobacteriumspp.,Acinetobacterspp., andLegionellaspp. were detected in all PCR positive samples. More importantly, elevated proportions or new appearance of toxin-producing cyanobacteria (e.g.,Microcystisspp.) and pathogenic species (e.g.,Salmonella enterica) were evident in local tap water samples after the extreme rainstorm event in Zhengzhou on July 20, 2021, and Typhoon In-Fa Landfall. High pathogen relative abundances were found to be significantly correlated with high outdoor temperatures. This underscores the need for enhanced drinking water treatment protocols during and following extreme rainfall events and/or periods of high temperatures, particularly relevant in the face of global climate change.