Overview of the Nature, Extent, Health Risks, and Treatment of Metal-affected Drinking Water in Bangladesh

Better Life Laboratories, Inc. is a nonprofit organization. It conducts scientific research and provides technical expertise, equipment, and training to help needy people around the world.

The 2 Major Hypotheses about the Source of Arsenic in Bangladesh’s Tubewell Water

Hypothesis #1: The arsenic is being released by oxidizing pyrite minerals.
- According to this hypothesis, arsenic is initially associated with a poorly soluble pyrite mineral (FeAsS or FeS₂) that is underwater in a reducing environment. This arsenic is released when the pyrite is aerated by lowering the water table during groundwater pumping (see Figure 8).
- In this scenario, groundwater pumping for irrigation raises the arsenic concentration of drinking water.
- Advocates of this hypothesis used the popular press to advance the untested idea of restricting irrigation to prevent the release of arsenic into groundwater. Their proposal to restrict irrigation in a famine-prone country of 120,000,000 is a very serious matter.

Figure 8. The hypothesized release of arsenic from pyrite during groundwater pumping.

Hypothesis #2: The arsenic is being released from non-pyrite minerals.
- According to this hypothesis, arsenic is released from the solid phase into groundwater by dissolution in a reducing environment.
- Arsenic might also be released as arsenate or arsenite by anion exchange with chloride, phosphate, or other anions.
- The use of groundwater for irrigation should not significantly effect its arsenic concentration. Since irrigation is crucial for maintaining Bangladesh’s food supply, it should NOT be stopped.

E-mail the President of Better Life Laboratories, Seth H. Frisbie, Ph.D. (shf3@cornell.edu).
Write us at Better Life Laboratories, 293 George Rd., East Calais, VT 05650, USA.