Spatial model of groundwater contamination risks from pit-latrines in a low-income country

Hinton, Rebekah G.K. and Kalin, Robert M. and Kanjaye, Modesta B. and Mleta, Prince and Macleod, Christopher J.A. and Troldborg, Mads (2024) Spatial model of groundwater contamination risks from pit-latrines in a low-income country. Water Research, 267. 122734. ISSN 0043-1354 (https://doi.org/10.1016/j.watres.2024.122734)

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Abstract

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 2020-2070 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 2020-2070, 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 2020-2070. Change is necessary to prevent SDG6’s push for sanitation undermining its goal of clean water.

ORCID iDs

Hinton, Rebekah G.K. ORCID logoORCID: https://orcid.org/0000-0001-5238-1405, Kalin, Robert M. ORCID logoORCID: https://orcid.org/0000-0003-3768-3848, Kanjaye, Modesta B., Mleta, Prince, Macleod, Christopher J.A. and Troldborg, Mads;
CORE (COnnecting REpositories)