Guo Danlu, Thomas Jacqueline, Lazaro Alfred Boniphace, Matwewe Fatuma, Johnson Fiona
Department of Infrastructure Engineering, The University of Melbourne, Parkville, Australia.
Ifakara Health Institute, Ifakara, Morogoro, Tanzania; School of Civil Engineering, The University of Sydney, Darlington, Australia.
Sci Total Environ. 2021 Apr 1;763:142932. doi: 10.1016/j.scitotenv.2020.142932. Epub 2020 Oct 10.
Climate change is expected to increase the prevalence of water-borne diseases especially in developing countries. Climate-resilient drinking water supplies are critical to protect communities from faecal contamination and thus against increasing disease risks. However, no quantitative assessment exists for the impacts of short-term climate variability on faecal contamination at different drinking water sources in developing countries, while existing understanding remains largely conceptual. This critical gap limits the ability to predict drinking water quality under climate change or to recommend climate-resilient water sources for vulnerable communities. This study aims to provide such quantitative understanding by investigating the relationships between faecal contamination and short-term climate variability across different types of water sources. We collected a novel dataset with over 20 months' monitoring of weather, Escherichia coli (E. coli) and total coliforms, at 233 different water sources in three climatically different regions in Tanzania. We then took a rigorous statistical analysis with Bayesian hierarchical models, to relate both contamination occurrence and amount to climate variability. The model results explained the temporal variability in drinking water faecal contamination using climate predictors, and also revealed the climate sensitivity of faecal contamination for individual water sources. We found that: a) short-term climate variability and baseline contamination levels can explain about half the observed variability in faecal contamination (R ≥ 0.44); b) increased contamination was most consistently related to recent heavy rainfall and high temperature across different water sources; c) unimproved water sources such as the unprotected dug wells have substantially higher climate sensitivity. Based on these results, we can expect substantial increases in drinking water contamination risks across tropical Sub-Saharan Africa and South-East Asian developing countries under a warmer climate, which highlight the urgent need of protecting vulnerable communities from the severe climate impacts.
预计气候变化将使水传播疾病的流行率上升，尤其是在发展中国家。具备气候适应能力的饮用水供应对于保护社区免受粪便污染从而降低疾病风险至关重要。然而，目前尚无关于短期气候变率对发展中国家不同饮用水源粪便污染影响的定量评估，而现有认识在很大程度上仍停留在概念层面。这一关键差距限制了预测气候变化下饮用水质量的能力，也限制了为脆弱社区推荐具备气候适应能力的水源的能力。本研究旨在通过调查不同类型水源中粪便污染与短期气候变率之间的关系，提供这样的定量认识。我们收集了一个新颖的数据集，对坦桑尼亚三个气候不同地区的233个不同水源进行了20多个月的天气、大肠杆菌和总大肠菌群监测。然后，我们使用贝叶斯分层模型进行了严格的统计分析，以将污染发生情况和污染量与气候变率联系起来。模型结果用气候预测因子解释了饮用水粪便污染的时间变异性，还揭示了各个水源粪便污染的气候敏感性。我们发现：a）短期气候变率和基线污染水平可以解释约一半观察到的粪便污染变异性（R≥0.44）；b）不同水源中污染增加最一致地与近期暴雨和高温相关；c）未改善的水源，如未加保护的挖井，气候敏感性显著更高。基于这些结果，我们预计在气候变暖的情况下，热带撒哈拉以南非洲和东南亚发展中国家的饮用水污染风险将大幅增加，这突出了保护脆弱社区免受严重气候影响的迫切需求。
