COVER STORY
SCARCE SUPPLY Women queue at the water pump in an Ethiopian village.
KEEPING IT CLEAN The chemical industry is finding ways to secure and expand GLOBAL WATER SUPPLIES PATRICIA L SHORT, C&EN LONDON
WATER. It's one of the simplest, most abundant molecules in the world. Increasingly, though, water supplies are undergoing extreme swings. Violent storms and floods bring it in ferocious abundance. Or drought and desertification create crippling shortages. The mismatch of need and abundance reaches across the globe, from developed to developing countries. In the U.S., for example, water levels have dropped dramatically at Hoover Dam and Lake Mead, as a booming population draws heavily on water supplies. Meanwhile, the aquifers of the Great Plains are being depleted by irrigation. Officials in Yemen, on the tip of the Saudi Arabian peninsula, are concerned about the dwindling water reserves supplying the capital city, Sanaa. A rapidly expanding population and increasing use of water for irrigation are fast drawing down the citys water reserves. In fact, officials there are beginning to contemplate moving the
historic capital and most of its population to the Red Sea Coast, where desalination could maintain water supplies. As Michael E. Campbell, chairman of Arch Chemicals, told the American chapter of the Société de Chimie Industrielle in September, water shortages affect 450 million people worldwide, and this number will grow with an ever-expanding human population. Even where there is water, it's often too contaminated to drink without risking serious illness. The World Health Organization (WHO) estimates that about 1.2 billion people worldwide lack any access to clean drinking water and that 2 million people a year—many of them children and elderly—die because of drinking contaminated water. Seeing both human need and, someday at least, profits, companies in the chemical industry have begun developing a wide range of technologies that can help secure WWW.CEN-0NLINE.ORG
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safe drinking water for the world's poor. Usually the projects are offshoots of technology that companies are developing for profit-generating business. Take arsenic contamination, one of the major culprits in impure water supplies around the world, for example. Far from being the deliberately deployed weapon of drawing-room murder mysteries, this element is a more insidious mass poisoner that can be an unanticipated result of good public health intentions. In Bangladesh, deep wells that were dug in the 1950s and 1960s to help control the spread of cholera (a diarrheal illness caused by drinking surface waters contaminated with the bacterium Vibno cholerae) had an unintended consequence that only later appeared. The aquifer water contained hundreds of micrograms per liter of naturally occurring arsenic, well beyond the international standard of 10 μg/L. Even though the problem is widely rec-
COVER STORY
ognized, an additional 4 million such tube wells were installed in Bangladesh in the past decade. The result is that as much as one-fourth of the country's population is drinking water containing 10 to 50 times the amount of arsenic that is considered safe. And arsenic contamination is not just a problem for the Indian subcontinent. Even in parts of the U.S., drinking water supplies cannot meet the new more stringent stand ard of 10 ppb (10 μg/L) of arsenic, which was recently lowered by the Environmen tal Protection Agencyfrom50 ppb. In fact, according to WHO, arsenic contamination affects tens of millions of people in more than 20 countries around the world. ITS IMPORTANCE was highlighted this spring by the establishment of a new award in the field of water treatment. In February 2005, the National Academy of Engineer ing established the Grainger Challenge Prize to encourage U.S. development of technologies for improving living stand ards throughout the world. This first com petition addressed the challenge of design ing an affordable system to reduce arsenic levels in drinking water to below 50 μg/L. The top prize, worth $1 million, was awarded to analytical chemistry professor Abul Hussam of George Mason University, in Virginia. Hussam was recognized for his design of a simple, inexpensive system for filtering naturally occurring arsenic from drinking water (G&EN, Feb. 12, page 19). The second award, worth $200,000,
BEST
went to a team led by chemical engi neering professor Arup K. SenGupta of Lehigh University in Pennsylvannia, who worked with the Denver-based nonprofit organi zation Water For People to develop an alumina-based ionexchange column that attaches to well pumps. The third award of $100,000 went to Procter & Gamble's Children's Safe Drinking Water Program, which has provided mil lions of sachets of the company's PUR water-purification chemicals to communities in developing countries (C&EN, April 17,2006, page 39). Hussam's systems now are being manu factured in Bangladesh, and thousands of them, each costing less than $40, have been distributed. Some already have been in use for five years without signs of diminished performance. The technology addresses some of the concerns raised by nongovernmental organizations (NGOs) such as the U.K.'s WaterAid, whose consultants worry about the disposal of arsenic-laden wastes.
POISONED WELL?
As many as one-quarter of Bangladeshis drink water pumped from aquifers with high arsenic levels.
WaterAid, a charity established in 1980 by British water sup pliers, teams with United Nations agen cies such as UNICEF to work with "the poorest of the poor," as David Williamson, a consultant with WaterAid, puts it. The organization's emphasis, he says, is primarily on nonchemical means of protecting water sup plies. iCWe are looking at protecting water sources—springs, for example—to keep them clean. We are not looking at treat ment, if at all possible—that's not sustain able," he says. WaterAid also monitors the arsenic con tent of waterfromwells in the Indian sub continent, South America, and wherever else there is a local problem. Williamson cautions that solutions to water issues can bring on their own problems. "The danger of removing the arsenic is that you then have to do something with it," he notes.
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dilute chlorine solution developed by the Washington, D.C.-based Population Services International (PSI), the Centers for Disease Control 8c Prevention, and the Pan American Health Organization. "We have provided more than 600 million L of safe drinking water over the past three years," says Charlotte Otto, global external relations officer at P&G. For example, P&G donated millions of PUR sachets, which combine calcium hypochlorite with a coagulant, for the East
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1887 \ t - \ MIT researcher Ellerr Swal low Richards conducts first * comprehensive study of - ' drinking water. Her work * Jeads tçtthe first water-qual1854 < ity standards and construcJohn Snow, a London . physician, suspects that ς tion of sewage treatment water from the Broad Street \ plants. * pump is the source of a ^cholera epidemic. To test' EARLY 1900s ^Chemists at Maryland * his theory, Snow reviews death records of area chol- * 7 Health Department discover that the introduction of era victims and interviews househpJdvrpembers, After ' * < small amounts of chlorine 1 is he;p£esents his findings , s t 4t> drïrçking water rids it of •^ to'coiftmunity leaders, the. , bacterja, viruses, and other microorganisms. pump hahcjlé is removed, _t ending the^choléra épi- v ^
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The company is "continuing to evalu ate all options to develop this system for the developing world and also looking at pockets of the developed world where this might be valuable," Mink says. Arch Chemicals' involvement in a safe drinking water program reflects the com pany's relationship with P&G, to which it supplies the calcium hypochlorite in P&G's PUR sanitization sachets. The partnership focuses on provision of two householdlevel technologies to disinfect drinking water: PUR sachets and WaterGuard, a
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