van Geen Alexander, Ahmed K M, Seddique A A, Shamsudduha M
Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964, USA.
Bull World Health Organ. 2003;81(9):632-8. Epub 2003 Nov 14.
To monitor the effectiveness of deep community wells in reducing exposure to elevated levels of arsenic in groundwater pumped from shallower aquifers.
Six community wells ranging in depth from 60 m to 140 m were installed in villages where very few of the wells already present produced safe water. By means of flow meters and interviews with villagers carrying water from the community wells, a study was made of the extent to which these were used during one year. The results were compared with household and well data obtained during a previous survey in the same area.
The mean arsenic concentration in water pumped from wells already in use in the villages where the community wells, were installed was 180 +/- 140 micrograms/l (n = 956). Monthly sampling for 4-11 months showed that arsenic levels in groundwater from five of the six newly installed wells were consistently within the WHO guideline value of 10 micrograms/l for drinking-water. One of these wells met the Bangladesh standard of 50 micrograms/l arsenic but failed to meet the WHO guideline values for manganese and uranium in drinking-water. The community wells were very popular. Many women walked hundreds of metres each day to fetch water from them. On average, 2200 litres were hand-pumped daily from each community well, regardless of the season.
A single community well can meet the needs of some 500 people residing within a radius of 150 m of it in a densely populated village. Properly monitored community wells should become more prominent in campaigns to reduce arsenic exposure in Bangladesh. Between 8000 and 10,000 deep community wells are needed to provide safe water for the four to five million people living in the most severely affected parts of the country.
监测深层社区水井在减少从较浅含水层抽取的地下水中高浓度砷暴露方面的效果。
在几乎没有现有水井能产出安全饮用水的村庄安装了6口深度在60米至140米之间的社区水井。通过流量计以及对从社区水井取水的村民进行访谈，研究了这些水井在一年中的使用程度。将结果与同一地区先前调查中获得的家庭和水井数据进行了比较。
在安装社区水井的村庄中，已使用水井抽取的水中砷的平均浓度为180±140微克/升（n = 956）。在4至11个月的每月采样显示，6口新安装水井中有5口水井的地下水中砷含量始终在世界卫生组织饮用水10微克/升的指导值范围内。其中一口水井符合孟加拉国50微克/升砷的标准，但未达到世界卫生组织饮用水中锰和铀的指导值。社区水井非常受欢迎。许多妇女每天步行数百米从这些水井取水。无论季节如何，平均每口水井每天手动抽取2200升水。
在人口密集的村庄，一口社区水井能够满足其半径150米范围内约500人的需求。经过适当监测的社区水井在孟加拉国减少砷暴露的运动中应会变得更加突出。需要8000至10000口深层社区水井为该国受影响最严重地区的400万至500万人提供安全饮用水。
