Environmental Science

Water Treatment Plants

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Science  08 Apr 2005:
Vol. 308, Issue 5719, pp. 169
DOI: 10.1126/science.308.5719.169a

Long-term ingestion of low concentrations of arsenic is detrimental to human health, yet in several countries around the world, large populations are constantly exposed to drinking water contaminated with arsenic. In Bangladesh, arsenic concentrations exceed World Health Organization guidelines in 60% of the groundwater. Arsenic can be removed by filtration and via adsorbents, such as natural zeolites, but there still is a need for simple and cost-effective methods using materials that are readily available in developing countries.

Al Rmalli et al. show that the dried pulverized roots of the water hyacinth can rapidly remove arsenic from water. The method is effective for both arsenite [As(III)] and arsenate [As(V)] and requires comparatively little material (50 μg of As are adsorbed per g of roots in 24 hours). Water hyacinths grow abundantly in ponds, lakes, and rivers in Bangladesh, India, and other tropical and subtropical countries. The simplicity of the method suggests that these plants may be useful in the treatment of drinking water, particularly in rural areas. — JFU

J. Environ. Monit. 7, 279 (2005).

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