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

http://dx.doi.org/10.1289/ehp.1206028



Table 1. Summary of selected studies that assessed groundwater or soil contamination associated with pit latrines.a
Source Country No. of latrines in studyb Experimental design Subsurface conditions Sampling time frame Water quality parametersc Conclusions
Abbreviations: Co, cobalt; Cu, copper; Fe, iron; Na, sodium; Zn, zinc.
aOnly studies that either directly assessed the transport of contaminants from pit latrines or studies that applied statistical methods to estimate a measure of risk associated with the presence of pit latrines are included. bNo specific data were provided on the density or number of pit latrines in the study area. cCulture-based assays were used for all microbiological tests, except for Verheyen et al. (2009), who used genotyping methods.
Vinger et al. 2012 South Africa 15 Sampled existing wells No data June–July Ammonia, nitrate, nitrite Higher levels of contaminants observed at distances < 11 m from pit latrines
Pujari et al. 2012 India 7 Sampled existing wells Fine loamy silt, sandy loam, intermittent clay Summer and monsoon seasons Fecal coliforms, total dissolved solids, nitrate No to low levels of nitrate and fecal coliforms observed
Banerjee 2011 India 12 Installed test wells Saturated and unsaturated soils of gravel, sand, silt, clay, and laterite Premonsoon and monsoon seasons Total coliforms, fecal coliforms, chloride solution used as tracer Movement of chloride tracers and coliforms limited to < 10.2 m from pits
Verheyen et al. 2009 Benin 220 Sampled existing wells No data Wet and dry seasons, 2003–2007 Adenovirus, rotavirus Viral contamination of groundwater associated with latrine proximity
Dzwairo et al. 2006 Zimbabwe 3 Installed test wells Saturated and unsaturated sandy soils February–May 2005 Ammonia, nitrate, turbidity, pH, conductivity, total coliforms, fecal coliforms Fecal coliform movement greatly reduced > 5 m from pits; all nitrate levels and 99% of ammonia levels met WHO drinking water standards
Zingoni et al. 2005 Zimbabwe Not specified Sampled existing wells and installed test wells No data No data Na, Zn, Cu, Co, Fe, phosphate, nitrate, total coliforms, fecal coliforms Elevated levels of nitrate and coliform bacteria in most parts of study area
Mafa 2003 Botswana Not specified Sampled existing wells Fractured rock overlain by alluvial sediment, clay, sand, and weathered rock July and August 2000 Broad set of hydrochemical analyses Elevated levels of nitrate in several zones where pit latrines were common
Banks et al. 2002 Kosova, Moldova, Siberia Not specified Sampled existing wells and springs No data 1996–2000 Chloride, sulfate, potassium, nitrate Elevated levels of nitrate likely from latrines
Howard et al. 2003 Uganda Not specified Sampled protected springs Highly variable: clay to sandy soils Monthly, March 1998 through April 1999 Fecal streptococci, fecal coliforms, nitrate No significant relationship between microbiological contamination and pit latrine proximity
Still and Nash 2002 South Africa 1 Installed test wells No data Bimonthly, 2000–2002 Fecal coliforms, nitrate Low levels of nitrate (< 10 mg/L) and fecal coliforms (10 cfu/100 mL) found > 1 m of latrine
Ahmed et al. 2002 Bangladesh Not specified Sampled existing wells Two aquifer systems; clay, silt, and fine to coarse sand 2- to 8-week intervals, 1998–1999 Fecal streptococci, fecal coliforms, broad set of hydrochemical analyses Bacteriological water quality generally good (< 10 fecal coliforms/100 mL); water quality poorly correlated with sanitary surveys
Chidavaenzi et al. 2000 Zimbabwe 2 Installed test wells Stratified fine-grain sandy soils Wet and dry seasons Nitrogen, coliforms Rapid reductions in coliform, sulfate, and nitrogen levels within 5 m from pits; contami­nation present up to 20 m
Jacks et al. 1999 Botswana 4 Sampled existing wells Well-drained and poorly drained soils No data Phosphorous, nitrogen isotopic ratios, chloride Variable nitrate leaching from pit latrines
Tandia et al. 1999 Senegal Not specified Sampled existing wells Fine to coarse sand July and November 1989 Broad set of hydrochemical analyses, fecal coliforms Nitrate contamination in water strongly correlated with latrine proximity
Nichols et al. 1983 USA 8 Installed test wells 3 latrines on clayey soil; 3 on shallow loam; 2 on sand; all soils well-drained June and August 1975–1979 Nitrate, phosphorus, fecal coliforms Latrines with peat liners reduced movement of phosphorus and fecal coliforms but not nitrate.
Lewis et al. 1980 Botswana 30 pit latrines in the study area Sampled existing wells and test wells Clayey soils and fissured rock October 1977 through February 1978 Broad set of hydrochemical analyses, E. coli, chloride solution used as tracer Contamination of wells near latrine with E. coli and nitrate; rapid transport of chloride tracer
Baars 1957 Netherlands Not specified Sampled soil and existing wells Unsaturated sandy soils September 1951 and January and March 1952 Ammonia, E. coli, nitrate Contamination in soil samples limited to < 1.5 m from latrines
Dyer 1941 India 1 Installed test wells Saturated and unsaturated alkaline alluvium soils December–September Chloride, nitrate, total coliforms Movement of total coliforms limited to < 7 m from pit
Caldwell 1938a USA 3 Installed test wells Fine gravel to clayey soils May–November 1933 Bacillus aerogenes, anaerobes, odor, pH, B. coli B. coli movement limited to 3 m from pits
Caldwell 1938b USA 1 Installed test wells Fine gravel to clayey soils November 1932–November 1933 Nitrate, dissolved oxygen, chloride, nitrite, pH, odor, colon aerogenes group, B. coli, anaerobes Limited movement of B. coli to 3 m from pit and chemicals to 24 m
Caldwell and Parr 1937 USA 8 bored hole latrines Installed test wells Partially saturated fine gravel to clayey soils May 1932–May 1933 Nitrate, dissolved oxygen, chloride, nitrite, pH, odor, colon aerogenes group, B. coli, anaerobes Movement of bacteria and chemicals to within 10 m and 26 m of latrine, respectively
Caldwell 1937b USA 1 envelope pit latrine Installed test wells Unsaturated fine gravel to clayey soils May–November 1933 Colon aerogenes group, pH, odor, B. coli, anaerobes Bacteria greatly reduced to within 2 m from pit
Caldwell 1937a USA 1 Installed test wells Saturated fine gravel to clayey soils August 1932–November 1933 Colon aerogenes group, pH, odor, B. coli, anaerobes Movement of bacteria to within 25 m of latrine
Kligler 1921 USA 50 Sampled soil at varying distances Saturated and unsaturated sand, sandy clay, and clay Wet and dry seasons, 1918–1919 B. coli, B. aerogenes Bacterial movement limited to < 5.5 m from pit