Pit latrines and their impacts on groundwater quality : a systematic review

Pit latrines are one of the most common human excreta disposal systems in low -income countries, and their use is on the rise as countries aim to meet the sanitation-related target of the Millennium Development Goals. There is concern, however, that pit latrine discharges of chemical and microbial contaminants to groundwater may negatively affect human health. Our goals were to calculate global pit latrine coverage, systematically review empirical studies of the impacts of pit latrines on groundwater quality; evaluate latrine siting standards, and to identify knowledge gaps regarding the potential for and consequences of groundwater contamination by latrines. Existing survey and population data are used to calculate global pit latrine coverage. Reviewed is the scientific literature on the occurrence of contaminants originating from pit latrines and considered the factors affecting transport of these contaminants. Data were extracted from peer-reviewed articles, books and reports identified using Web of Science SM , PubMed, Google, and document reference lists. Estimated  isthat approximately 1.77 billion people use pit latrines as their primary means of sanitation. Studies of pit latrines and groundwater are limited and have generally focused on only a few indicator contaminants. Although groundwater contamination is frequently observed downstream of latrines, contaminant transport distances, recommendations based on empirical studies, and siting guidelines are variable and not well aligned with one another. In order to improve environmental and human health, future research should examine a larger set of contextual variables, improve measurement approaches, and develop better criteria for siting pit latrines. [authors abstract]