The Journal of Health, Population and Nutrition
Vol. 35, No. 1, 2016, pp. 1-10
Bioline Code: hn16026
Full paper language: English
Document type: Research Article
Document available free of charge
The Journal of Health, Population and Nutrition, Vol. 35, No. 1, 2016, pp. 1-10
© Copyright 2016 - The Journal of Health, Population and Nutrition
Safe distances between groundwater-based water wells and pit latrines at different hydrogeological conditions in the Ganges Atrai floodplains of Bangladesh|
Islam, M. Sirajul; Mahmud, Zahid Hayat; Islam, M. Shafiqul; Saha, Ganesh Chandra; Zahid, Anwar; Ali, AHM Zulfiquar; Hassan, M. Qumrul; Islam, Khairul; Jahan, Hasin; Hossain, Yakub; Hasan, M. Masud; Cairncross, Sandy; Carter, Richard; Luby, Stephen P.; Cravioto, Alejandro; Endtz, Hubert Ph.; Faruque, Shah M. & Clemens, John D.
Background: Groundwater drawn from shallow tubewells in Bangladesh is often polluted by nearby pit latrines,
which are commonly used toilets in rural and sub-urban areas of the country.
Methods: To determine the minimum safe distance of a tubewell from a pit latrine in different hydrogeological
conditions of Bangladesh, 20 monitoring wells were installed at three study sites (Manda, Mohanpur and Bagmara)
with the vertical and horizontal distances ranging from 18–47 to 2–15 m, respectively. Water samples were
collected three times in three seasons and tested for faecal coliforms (FC) and faecal streptococci (FS) as indicators
of contamination. Soil samples were analysed for texture, bulk density and hydraulic conductivity following
standard procedures. Sediment samples were collected to prepare lithological logs.
Results: When the shallow aquifers at one of the three sites (Mohanpur) were overlained by 18–23-m-thick
aquitards, the groundwater of the monitoring wells was found contaminated with a lateral and vertical distances of
2 and 31 m, respectively. However, where the aquitard was only 9 m thick, contamination was found up to lateral
and vertical distances of 4.5 and 40.5 m, respectively. The soil textures of all the sites were mainly composed of
loam and sandy loam. The hydraulic conductivities in the first aquifer at Manda, Mohanpur and Bagmara
were 5.2–7.3, 8.2 and 1.4–15.7 m/h, respectively.
Conclusions: The results showed that the safe distance from the tubewell to the pit latrine varied from site to
site depending on the horizontal and vertical distances of the tubewell as well as hydrogeological conditions of a
Bacterial contamination; Hydrogeological condition; Pit latrine; Safe distance; Tubewells
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