Division of Environmental Engineering, Faculty of Engineering, Hokkaido University , Sapporo 060-8628, Japan.
Environ Sci Technol. 2014 May 6;48(9):4744-9. doi: 10.1021/es500578s. Epub 2014 Apr 14.
Water quality monitoring and microbial risk assessment are important to ensure safe water for drinking, recreational, and agricultural purposes. In this study, we applied a microfluidic quantitative PCR (MFQPCR) approach to simultaneously quantify multiple waterborne pathogens in a natural freshwater lake in Hokkaido, Japan, from April to November, 2012. Tens of thousands of geese stopped over at this lake during their migration in spring and fall. Because lake water is used for irrigation of the surrounding agricultural area, we assessed infection risks through irrigation water usage based on pathogen concentrations directly measured by MFQPCR. We detected various pathogens in the lake water, particularly during the bird migration seasons, suggesting that migratory birds were the main source of the pathogens. However, neither counts of geese nor fecal indicator bacteria were good predictors of pathogen concentrations. On the basis of quantitative microbial risk assessment, concentrations of Campylobacter jejuni and Shigella spp. in water samples were above the concentrations that can potentially cause 10(-4) infections per person per year when water is used to grow fresh vegetables. These results suggest that direct and simultaneous multipathogen quantification can provide more reliable and comprehensive information for risk assessment than the current fecal indicator-based approach.
水质监测和微生物风险评估对于确保饮用水、娱乐用水和农业用水的安全非常重要。本研究应用微流控定量 PCR（MFQPCR）方法，于 2012 年 4 月至 11 月，对日本北海道一个天然淡水湖中多种水传播病原体进行同时定量检测。成千上万的鹅在春秋两季迁徙过程中在此湖停留。由于湖水被用于灌溉周围的农业区，我们根据 MFQPCR 直接测量的病原体浓度，通过灌溉水的使用来评估感染风险。我们在湖水中检测到各种病原体，尤其是在鸟类迁徙季节，表明候鸟是病原体的主要来源。然而，鹅的数量和粪便指示菌都不是病原体浓度的良好预测指标。基于定量微生物风险评估，当用湖水种植新鲜蔬菜时，水样中弯曲杆菌和志贺氏菌的浓度超过了可能导致每年每人 10(-4)次感染的浓度。这些结果表明，直接和同时的多病原体定量检测可以比当前基于粪便指示菌的方法提供更可靠和全面的风险评估信息。
