Pit Latrines and Their Impacts on Groundwater Quality: A Systematic Review

Abstract

Background: 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 discharges of chemical and microbial contaminants from pit latrines to groundwater may negatively affect human health.Objectives: Our goals were to a) calculate global pit latrine coverage, b) systematically review empirical studies of the impacts of pit latrines on groundwater quality, c) evaluate latrine siting standards, and d) identify knowledge gaps regarding the potential for and consequences of groundwater contamination by latrines.Methods: We used existing survey and population data to calculate global pit latrine coverage. We reviewed 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 ScienceSM, PubMed, Google, and document reference lists.Discussion: We estimated that 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.Conclusions: 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.

Polioviruses and other Enteroviruses

“…Yet the requirements depending on the temperature only mandate 1 hour up to 2 weeks. Consistent with pit latrines as a source of this viral contamination is the observation that most of the ground water contamination that was associated with pit latrines was reported within 50 meters downstream of the latrines (Tillett, 2013;Verheyen et al, 2009) especially in freshly dug latrines where establishment of biofilm and maximum soil-filtering may take months to establish (Graham and Polizzotto, 2013). Viral contamination of ground water has often been associated with proximity to pit latrines where transport of the virus may occur through ground water flow in the upper part of the soil and/or by surface water runoff (Abbaszadegan et al, 2003;Borchardt et al, 2003;Borchardt et al, 2004;Fout et al, 2003;Graham and Polizzotto, 2013;Keswick et al, 1982;Sagik et al, 1980;Tillett, 2013;Verheyen et al, 2009) (see also Section 2.0).…”

“…These include directly stripping EVs from the surfaces of foods, hands, and other surfaces by adequate washing, disinfecting materials and surfaces used for food production, heating the food to inactivate virus, and using uncontaminated or treated water. Unfortunately, facilities that hygienically separate human excreta from human contact are unavailable for approximately 2.4 billion people or one third of the current global population (Graham and Polizzotto, 2013;WHO and UNICEF, 2015).…”

“…The amount of contamination detected depends on hydrological and soil condition, rainfall including the height of the groundwater table and soil condition, the methods chosen for detection, and the viral target (Graham and Polizzotto, 2013;Rao et al, 1986;Tillett, 2013). Enteroviruses were recovered from the walls of the latrine, surface soil, soil at a depth of 10 cm, food preparation area and inside the home, and on toys and dishes (Pickering et al, 2012).…”

Water Resources Sustainability of Ulaanbaatar City, Mongolia

“…Moreover, the unplanned expansion of Ger districts around the city has created a high potential for water contamination due to a lack of appropriate sanitation and sewage systems, which are based on pit latrines. By consequence, the area around UB has changed dramatically with the rapid growth of the city, which could have severe environmental consequences [16][17][18].…”

Physico-Chemical Quality of Groundwater in Keta South, Ghana

“…Examples of these human activities include poor waste disposal practices, poor protection of well heads, proximal siting of toilet facilities and sewage systems close to groundwater abstraction points and in catchment areas, and the mode of abstraction. According to Graham & Polizzotto (2013), these human activities make groundwater vulnerable to contamination. Natural conditions such as geology of landcover and flooding caused by storm surges also expose groundwater to contamination.…”