Pollution dynamics of groundwater analyzed by microbial community structures and stable isotopes

对尼泊尔加德满都的浅层地下水进行了实地调查，收集了包括微生物群落结构和稳定同位素在内的水文和水质原始数据。 水文因素（雨水入渗和地下水位上升）引发微生物污染。多口威尔斯井中存在BSL 2级以上病原菌，畜禽粪便可能是该地区的污染源之一。地统计学分析表明，人口密集和下水道受损的地区可能是污染的热点。多因素分析表明，除水质外，自来水长期短缺和间断供应、水源储存和水源不稳定与腹泻发生显著相关。因此，卫生基础设施的明显改善并不一定有助于有效减少对健康的影响，应在了解各种用水的基础上制定总体计划。

Field surveys of shallow groundwater were conducted to collect primary data of hydrology and water quality including microbial community structures and stable isotopes in Kathmandu, Nepal. Hydrologic factors (rainwater infiltration and water table increase) triggered the microbial contamination. Pathogens (BSL 2 or more) prevailed in multiple wells, livestock feces were supposedly one of the pollution sources in the area. Geostatistical analysis showed that districts with both dense population and damaged sewer might be hot spots of the pollution. Multivariate analysis showed that, in addition to water quality, chronic shortage and intermittent supply of piped water, storage of the water and instability of source were significantly related to diarrhoea occurrence. Thus, apparent improvement of sanitary infrastructures does not necessarily contribute for reducing health impact effectively and a master plan should be established on the basis of understanding the diverse water use.