A valid method for the determination of As by arsenomolybdate is now available. This method is more accurate, precise, and environmentally safe than the AgSCSN(CH2CH3)2 method (Tables 1, 2); and it is more accurate and affordable than the GFAAS method (Tables 1, 3).
Most importantly, the arsenomolybdate method is the only accurate, precise, and safe way to quantify As to less than the 10-µg/L WHO drinking water guideline without expensive or highly specialized laboratory equipment (Table 1). This suggests that developing countries such as Argentina, Bangladesh, Bolivia, Chile, China, India, Mexico, Nepal, Pakistan, Peru, and Thailand with limited access per capita to atomic absorption spectrometers or other sophisticated instruments for measuring As could lower their 50-µg/L drinking water standards to the more protective 10-µg/L WHO drinking water guideline if they used the arsenomolybdate method (Bhattacharya et al. 2002; Ng et al. 2003; UN 2004). Over 32,000,000 people from these countries drink water with As concentrations greater than their 50-µg/L national standards (Bhattacharya et al. 2002; Ng et al. 2003; UN 2004; Yu et al. 2003). This suggests over 170,000 people from these countries will die from skin, bladder, liver, or lung cancer caused by drinking water with more than 50 µg/L of As. If these countries complied with a 10-µg/L drinking water standard for As, perhaps by sharing safe water as was done in the 4 neighborhoods from this study, over 140,000 of these 170,000 lives could potentially be saved.
In particular, it is very important that the Government of Bangladesh lower its 50-µg/L drinking water standard for As. The rapidly increasing number of tubewells in Bangladesh suggests that the mortality rate from chronic As poisoning is also rapidly increasing. Lowering this standard will reduce exposure and save lives by encouraging the use of safer drinking water.
Finally, our surveys suggest that Bangladeshis will readily test and share their drinking water to meet the more protective 10-µg/L WHO guideline for As. More specifically, 85% of tubewell owners were concerned enough to retest their water for As within 1 year. And 90% of the tubewell owners that had over 10 µg/L of As actually gathered water from their neighbors.
