The Pollution Magnet РEighty-two thousand people die from cancer in Bangladesh every year, many due to arsenic poisoning. But building upon her discovery of a way to get rust nanoparticles to bind to arsenic, Vicki Colvin has invented a new, astonishingly easy way to clean the water supply: Saut̩ a teaspoon of rust in a mixture of oil and lye, which breaks down the rust into nano-sized pieces. Retrieve the rust particles with a household magnet. Then immerse the rust-covered magnet into a pot of contaminated water. Pull out the arsenic. The system is up to a hundred times more efficient than existing methods, and requires no electricity or manufacturing infrastructure, so even the poorest of villagers can use it.

Depending upon government regulations, Colvin’s extraction system should go global in as few as five years. Yet ultimately, Colvin, a professor of chemistry and chemical and biomolecular engineering at Rice University, has bigger plans. She sees her method as just the first step toward developing an easy point-of-use water-purification system that would cover virtually every pollutant. The filter would have a dipstick to tell you what’s in the water and a reader to tell you what you need to add to pull it out — perhaps silver nanoparticles to kill bacteria or a protein to capture pesticides.