London School of Hygiene & Tropical Medicine, London, UK.
Trop Med Int Health. 2014 Feb;19(2):186-94. doi: 10.1111/tmi.12229. Epub 2013 Nov 20.
The objective of this study was to investigate the quality of on-plot piped water and rainwater at the point of consumption in an area with rapidly expanding coverage of 'improved' water sources.
Cross-sectional study of 914 peri-urban households in Kandal Province, Cambodia, between July-August 2011. We collected data from all households on water management, drinking water quality and factors potentially related to post-collection water contamination. Drinking water samples were taken directly from a subsample of household taps (n = 143), stored tap water (n = 124), other stored water (n = 92) and treated stored water (n = 79) for basic water quality analysis for Escherichia coli and other parameters.
Household drinking water management was complex, with different sources used at any given time and across seasons. Rainwater was the most commonly used drinking water source. Households mixed different water sources in storage containers, including 'improved' with 'unimproved' sources. Piped water from taps deteriorated during storage (P < 0.0005), from 520 cfu/100 ml (coefficient of variation, CV: 5.7) E. coli to 1100 cfu/100 ml (CV: 3.4). Stored non-piped water (primarily rainwater) had a mean E. coli count of 1500 cfu/100 ml (CV: 4.1), not significantly different from stored piped water (P = 0.20). Microbial contamination of stored water was significantly associated with observed storage and handling practices, including dipping hands or receptacles in water (P < 0.005), and having an uncovered storage container (P = 0.052).
The microbial quality of 'improved' water sources in our study area was not maintained at the point of consumption, possibly due to a combination of mixing water sources at the household level, unsafe storage and handling practices, and inadequately treated piped-to-plot water. These results have implications for refining international targets for safe drinking water access as well as the assumptions underlying global burden of disease estimates, which posit that 'improved' sources pose minimal risks of diarrhoeal diseases.
本研究旨在调查一个快速扩大“改良”水源覆盖范围地区的田间管道水和雨水在消费点的质量。
2011 年 7 月至 8 月，在柬埔寨干丹省对 914 户城郊家庭进行了横断面研究。我们从所有家庭收集了关于水管理、饮用水质量以及可能与收集后水污染有关的因素的数据。从家庭水龙头的一个亚样本（n=143）、储存的自来水（n=124）、其他储存的水（n=92）和处理后的储存水（n=79）中采集饮用水样本，用于基本水质分析，检测大肠杆菌和其他参数。
家庭饮用水管理复杂，在任何特定时间和季节都会使用不同的水源。雨水是最常用的饮用水源。家庭在储水容器中混合不同的水源，包括“改良”水源和“非改良”水源。储存在水龙头中的自来水在储存过程中会变质（P<0.0005），从 520 cfu/100 ml（变异系数，CV：5.7）大肠杆菌增加到 1100 cfu/100 ml（CV：3.4）。储存的非管道水（主要是雨水）大肠杆菌平均计数为 1500 cfu/100 ml（CV：4.1），与储存的管道水无显著差异（P=0.20）。储存水的微生物污染与观察到的储存和处理行为显著相关，包括将手或容器浸入水中（P<0.005）以及使用无盖储水容器（P=0.052）。
在我们的研究地区，“改良”水源的微生物质量在消费点没有得到保持，这可能是由于家庭层面上混合水源、不安全的储存和处理行为以及处理不当的管道到田间水的综合原因。这些结果对完善国际安全饮用水获取目标以及全球疾病负担估计的基本假设具有影响，后者假定“改良”水源带来的腹泻病风险最小。
