Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow G1 1XJ, UK; The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, UK.
Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow G1 1XJ, UK.
Water Res. 2024 Dec 1;267:122734. doi: 10.1016/j.watres.2024.122734. Epub 2024 Nov 1.
Pit-latrines are central to achieving UN Sustainable Development Goal 6 (SDG 6) of ensuring "clean water and sanitation for all". Unless safely managed, pit-latrines result in groundwater contamination, which increases morbidity and mortality. Despite this, there have been no long-term spatial projections of future pit-latrine contamination risks. National survey data of over 100,000 water-points and 260,000 pit-latrines in Malawi was used to generate a novel, high-resolution model of pit-latrines from 2020 to 2070 under five population scenarios. The results here are presented as a 'business as usual' scenario of population growth and pit-latrine usage, predicting a three-fold increase in the number of current water-points at risk of short-distance microbial pit-latrine contamination between 2020 and 2070, with a seven-fold increase in number at the highest risk of contamination. Current nitrogen loading into pit-latrines is comparable to national fertiliser application. The model predicts 8.2 mega-tonnes of faecal nitrogen will be disposed of into subsequently abandoned pit-latrines between 2020 and 2070. Change is necessary to prevent SDG6's push for sanitation undermining its goal of clean water.
旱厕是实现联合国可持续发展目标 6（SDG 6）的核心，该目标旨在确保“人人享有清洁水和卫生设施”。如果旱厕不能得到安全管理，就会导致地下水污染，从而增加发病率和死亡率。尽管如此，目前还没有对未来旱厕污染风险进行长期的空间预测。本研究利用马拉维超过 10 万个水源点和 26 万个旱厕的全国调查数据，根据五种人口情景，生成了一个从 2020 年到 2070 年的新型高分辨率旱厕模型。研究结果以人口增长和旱厕使用的“照常营业”情景呈现，预测在 2020 年至 2070 年期间，目前面临短距离微生物旱厕污染风险的水源点数量将增加两倍，而污染风险最高的水源点数量将增加七倍。目前进入旱厕的氮负荷与全国化肥施用量相当。该模型预测，在 2020 年至 2070 年期间，将有 820 万吨粪便氮被排放到随后被废弃的旱厕中。为了防止 SDG6 推动卫生设施建设破坏清洁水目标，必须进行变革。
