UC Berkeley UC Berkeley Previously Published Works Title Pit latrines and their impacts on groundwater quality: a systematic review. Permalink https://escholarship.org/uc/item/7dn8t3qn Journal Environmental health perspectives, 121(5) ISSN 0091-6765 Authors Graham, Jay P Polizzotto, Matthew L Publication Date 2013-05-01 DOI 10.1289/ehp.1206028 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Review Pit Latrines and Their Impacts on Groundwater Quality: A Systematic Review Jay P. Graham1,2 and Matthew L. Polizzotto3 1Department of Environmental and Occupational Health, and 2Department of Global Health, George Washington University School of Public Health and Health Services, Washington, DC, USA; 3Department of Soil Science, North Carolina State University, Raleigh, North Carolina, USA with groundwater contamination by pit BACKGROUND : Pit latrines are one of the most common human excreta disposal systems in latrines. In particular, we a) calculated global low-income countries, and their use is on the rise as countries aim to meet the sanitation-related pit latrine coverage, b) systematically reviewed target of the Millennium Development Goals. There is concern, however, that discharges of chemi cal empirical studies of the impacts of pit latrines and microbial contaminants from pit latrines to groundwater may negatively affect human health. on ground water quality, c) evaluated latrine OB JECTIVES : Our goals were to a) calculate global pit latrine coverage, b) systematically review siting standards, and d) identified knowl- empirical studies of the impacts of pit latrines on groundwater quality, c) evaluate latrine siting edge gaps regarding the potential for and standards, and d) identify knowledge gaps regarding the potential for and consequences of ground- water contamination by latrines. 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 Methods 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 Global pit latrine coverage. We used exist- document reference lists. ing survey data to estimate the percentages of people per country who a) use pit latrines for 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 sanita tion, b) do not have any sanitation facili- on only a few indicator contaminants. Although groundwater contamination is frequently observed ties, and c) use groundwater sources for drink- downstream of latrines, contaminant transport distances, recommendations based on empirical ing water [see Supplemental Material, Table S1 studies, and siting guidelines are variable and not well aligned with one another. (http://dx.doi.org/10.1289/ehp.1206028)]. CONCLUSIONS : In order to improve environmental and human health, future research should Data from the most recent reports for each examine a larger set of contextual variables, improve measurement approaches, and develop better country were obtained from Demographic criteria for siting pit latrines. and Health Surveys (USAID 2012), Multiple KEY WORDS : groundwater, latrine, privy, sanitation, siting standards, water quality. Environ Health Indicator Cluster Surveys (UNICEF 2012), and Perspect 121:521–530 (2013). http://dx.doi.org/10.1289/ehp.1206028 [Online 22 March 2013] China’s Economic, Population, Nutrition, and Health Survey (WHO/UNICEF 2012a, 2012b). We included improved latrines [flush An estimated 2.6 billion people lack access into the ground and covered with a con- toilets and toilets that pour/flush to pit latrines to improved sanitation—defined as facilities crete slab or floor with a hole through which (water is poured by hand for flushing), venti- that hygienically separate human excreta from excreta falls. Unimproved pit latrines are lated improved latrines, and pit latrines with human contact [World Health Organization those without slabs or platforms. slabs] and unimproved latrines (traditional (WHO)/UNICEF 2010)]. Improved sanita- In concert with sanitation goals, the latrines, pit latrines without slabs, and shared tion includes water-based toilets that flush UN has also set explicit targets to increase latrines) when estimating pit latrine use (see into sewers, septic systems, or pit latrines; the proportion of the global population Supplemental Material, p. 2, for definitions of simple pit latrines; and ventilated improved using an improved drinking-water source types of sanitation). Composting toilets, con- pit latrines. There is strong evidence that (WHO/UNICEF 2012c). In the context of sidered improved facilities, were not included access to improved sanitation can reduce diar- low-income countries, water from improved in our analysis, nor were sanitation facilities rhea morbidity and mortality as well as soil- sources is frequently derived from ground- for which final disposal of human excreta is transmitted helminths (Albonico et al. 2008; water via protected springs, protected dug unknown (e.g., hanging latrines and bucket Cairncross et al. 2010b). wells, tube wells, and boreholes (UN 2008). latrines). For estimates of the proportions The United Nations (UN), through the Thus, the use of ground water (which typically of improved versus unimproved latrines, we Millennium Development Goals, has set a receives no subsequent treatment to improve assumed that unspecified latrines were split target of halving by 2015 the proportion of quality) for drinking water supplies is increas- evenly between improved and unimproved. the population without sustainable access ing dramatically (Rosa and Clasen 2010). Data for people without a sanitation facility to improved sanitation (WHO/UNICEF Because of the increasing uses of both pit include “no facility” and “open defecation 2012c). To achieve this target, approximately latrines and ground water resources in low- 1 billion people in urban areas and 900 mil- income countries, there is concern that pit Address correspondence to J.P. Graham, School of lion people in rural areas must gain access to latrines may cause human and ecological Public Health and Health Services, Department of improved sanitation by 2015 over the base- health impacts associated with microbiological Environmental and Occupational Health, George line year, 1990 (WHO/UNICEF 2012c). In and chemical contamination of ground water. Washington University, Washington, DC 20037 USA. Telephone: (202) 994-2392. E-mail: jgraham@ low-income countries [with a gross national Pit latrines generally lack a physical barrier, gwu.edu income per capita of ≤ US$1,025 (World such as concrete, between stored excreta and Both authors contributed equally to this article. Bank 2013)], many households use improved soil and/or ground water (van Ryneveld and Supplemental Material is available online (http:// or unimproved pit latrines because of their Fourie 1997). Accordingly, contaminants dx.doi.org/10.1289/ehp.1206028). low cost and availability (Cairncross et al. from pit-latrine excreta may potentially leach We thank T. Barto, D. Galan, R. Hinton, and three 2010a; Jain 2011). Improved pit latrines into ground water, thereby threatening human anonymous reviewers for helpful input to the analysis. The authors declare they have no actual or potential are the most basic and inexpensive form of health through well-water contamination. In competing financial interests. improved sanitation. They typically consist of this study, we assessed the known and mea- Received 18 September 2012; accepted 11 March a pit—circular, rectangular, or square—dug sured environmental health impacts associated 2013. Environmental Health Perspectives • VOLUME 121 | NUMBER 5 | May 2013 521 Graham and Polizzotto in bush/field.” National survey data do not Results 2007). The largest chemical concerns from typically charac terize shared facilities because Global pit latrine coverage. Globally, there is excreta disposed in on-site sanitation systems they are considered unimproved sanitation. great variability in latrine coverage. We esti- are considered to be nitrate [British Geological Therefore, for shared sanitation, we applied mate that approximately 1.77 billion people Survey (BGS) 2002; Fourie and Vanryneveld the average proportion of facilities that were around the world use some form of pit latrine 1995; Pedley et al. 2006], phosphate (Fourie pit latrines (44%) based on seven national as their primary means of sanitation [Figure 1; and Vanryneveld 1995), and chloride (BGS surveys that provided more detailed informa- see also Supplemental Material, Table S1 2002) (see Supplemental Material, Table S3). tion (see Supplemental Material, Table S1). (http://dx.doi.org/10.1289/ehp.1206028)]. Microbiological contaminants associated Groundwater use comprised both improved In addition, we estimate that 48% of people with pit latrines. Concentrations of most fecal and unimproved modes of accessing ground- using pit latrines use facilities charac terized micro organisms decline after excretion, but water, including tube wells and boreholes, as improved, whereas the remainder uses these micro organisms may still impair ground- protected wells, protected springs,