Emmett Interdisciplinary Program in Environment and Resources, School of Earth Sciences, Stanford University, Stanford, California 94305, USA.
Environ Sci Technol. 2012 Feb 21;46(4):2391-7. doi: 10.1021/es203177v. Epub 2012 Feb 9.
Currently, more than two-thirds of the population in Africa must leave their home to fetch water for drinking and domestic use. The time burden of water fetching has been suggested to influence the volume of water collected by households as well as time spent on income generating activities and child care. However, little is known about the potential health benefits of reducing water fetching distances. Data from almost 200, 000 Demographic and Health Surveys carried out in 26 countries were used to assess the relationship between household walk time to water source and child health outcomes. To estimate the causal effect of decreased water fetching time on health, geographic variation in freshwater availability was employed as an instrumental variable for one-way walk time to water source in a two-stage regression model. Time spent walking to a household's main water source was found to be a significant determinant of under-five child health. A 15-min decrease in one-way walk time to water source is associated with a 41% average relative reduction in diarrhea prevalence, improved anthropometric indicators of child nutritional status, and a 11% relative reduction in under-five child mortality. These results suggest that reducing the time cost of fetching water should be a priority for water infrastructure investments in Africa.
目前，非洲超过三分之二的人口必须离开家园去获取饮用水和家庭用水。有人认为，取水的时间负担会影响家庭所采集的水量，以及用于创收活动和儿童保育的时间。然而，对于减少取水距离可能带来的健康益处，人们知之甚少。本研究利用来自 26 个国家的近 20 万次人口与健康调查的数据，评估了家庭到水源的步行时间与儿童健康结果之间的关系。为了估计减少取水时间对健康的因果效应，本研究将淡水供应的地理差异作为家庭主要水源步行时间的工具变量，在两阶段回归模型中进行了单向分析。研究发现，步行到家庭主要水源的时间是五岁以下儿童健康的一个重要决定因素。单程步行到水源的时间减少 15 分钟，与腹泻患病率平均降低 41%、儿童营养状况的人体测量指标得到改善以及五岁以下儿童死亡率相对降低 11%有关。这些结果表明，减少取水的时间成本应成为非洲水基础设施投资的优先事项。
