Human virus and microbial indicator occurrence in public-supply groundwater systems: meta-analysis of 12 international studies | Présence de virus humains et indicateur microbien dans les systèmes aquifères utilisés pour l’alimentation en eau potable: méta-analyze de 12 études internationales La presencia de virus humanos y de indicadores microbianos en los sistemas de abastecimiento público de agua subterránea: metanálisis de 12 estudios internacionales 地下水公共供水系统中出现的人类病毒和微生物指标:12项国际研究中的元分析 Indicador de ocorrência de micróbios e vírus humano em sistemas de fornecimento de água subterrânea: meta-análise em 12 estudos internacionais
2017
Fout, G Shay | Borchardt, Mark A. | Kieke, Burney A. Jr | Karim, Mohammad R.
Groundwater quality is often evaluated using microbial indicators. This study examines data from 12 international groundwater studies (conducted 1992–2013) of 718 public drinking-water systems located in a range of hydrogeological settings. Focus was on testing the value of indicator organisms for identifying virus-contaminated wells. One or more indicators and viruses were present in 37 and 15% of 2,273 samples and 44 and 27% of 746 wells, respectively. Escherichia coli (E. coli) and somatic coliphage are 7–9 times more likely to be associated with culturable virus-positive samples when the indicator is present versus when it is absent, while F-specific and somatic coliphages are 8–9 times more likely to be associated with culturable virus-positive wells. However, single indicators are only marginally associated with viruses detected by molecular methods, and all microbial indicators have low sensitivity and positive predictive values for virus occurrence, whether by culturable or molecular assays, i.e., indicators are often absent when viruses are present and the indicators have a high false-positive rate. Wells were divided into three susceptibility subsets based on presence of (1) total coliform bacteria or (2) multiple indicators, or (3) location of wells in karst, fractured bedrock, or gravel/cobble settings. Better associations of some indicators with viruses were observed for (1) and (3). Findings indicate the best indicators are E. coli or somatic coliphage, although both indicators may underestimate virus occurrence. Repeat sampling for indicators improves evaluation of the potential for viral contamination in a well.
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