Once ingested, arsenic begins its slow assault on the human body. Its potency derives from its ill-fated position in the periodic table. Located directly beneath phosphorous, arsenic acts as its chemical doppleganger, binding with the same elements phosphorous normally binds to. The human body relies heavily upon phosphorous for its energy-storing bonds, but when sufficient levels of arsenic are consumed, arsenic displaces phosphorous. The result is a body starved of energy. In time the liver grows stressed and the skin blotched, eventually forming gangrenous sores. Cancer manifests in the skin, liver, kidneys and bladder, and eventually people die.

The Quest for a Filter

Dr. Hussam's interest in finding a solution to arsenic poisoning in fact began long before the competition was announced. As a child he grew up in rural Bangladesh, drinking from one of the government's tube wells that he later suspected, after the first reports of contamination aired, might be contaminated. His father, a physician by training, inspired had him with a love of chemistry, teaching him basic chemical principles and conducting experiments out of books with him. "By the time I was in eighth grade, I knew I wanted to be a chemist."

In 1982 he received his PhD in analytical chemistry from the University of Minnesota and in 1997 set out to see if his suspicions were founded and if the health of his and family members, whom still drank from the well, was in danger. The hardest part, he says, was designing a method for testing well water in the field. Arsenic is an extremely potent poison and can cause devastating effects when it comprises just one part in twenty million molecules of water - the concentration of a single murderer in all of New York City. After two years of work he had developed a reliable method and tested the well in his family's village. The results came in at more than three times the World Health Organization's designated safe limit.

With the help of his brother, a physician, and his chemistry mentor, he began working on a solution immediately and read though the available scientific literature. One study in particular caught his eye: arsenic levels had been shown to decline when allowed to flow over hydrous ferric oxide, or in layman's terms, rust. The arsenic molecules bound to it firmly leaving the water behind arsenic-free. Most promising of all was that the bond was so strong that the rust could be disposed of without any danger of the arsenic re-entering the soil. The only problem was that he would need a very high surface area of rust, much higher than a few rusted plates could provide.

If Dr. Hussam's filter was to be successful, it would also have to be practical. It could not depend on electricity as many parts of Bangladesh do not have a reliable source of power. It would have to be easy to install by people with little knowledge of how it worked. It would have to be operable for years without clogging or requiring a filter change. Most importantly, it would have to be inexpensive. Bangladesh is one of the poorest countries in the world, with nearly a third of its citizens living off of less than one dollar per day. A simple table-top Brita filter, which is not sophisticated enough to remove arsenic, could cost more than weeks' income.

Eventually, the solution came in iron turnings - those curly cues of waste iron and steel that result from lathing metal in machine shops. Dr. Hussam experimented with more than two hundred different designs, varying everything from the chemical pre-treatment of the metal to the size of the buckets containing them. Finally, after two years, he thought he had come up with a design that would work: a two-bucket system of layered charcoal, sand, and specially treated rust. Best of all, the data appeared to confirm its success. When asked what his emotions were during his "Eureka" moment, Dr. Hussam responded that though excited, "a scientist always has skepticism." The real question, he said, was how long it would work before it wore out.