From Washington, D.C., at a meeting of the American Chemical Society
Many Mexican communities have drinking water laced with unsafe levels of arsenic and unappealing amounts of sand and other solids. To make the water cleaner, Norma Alcantar, a chemical engineer at the University of South Florida in Tampa and her colleagues are working on an environmentally benign filtering process based on a plant found all over Mexico: the nopal cactus or prickly pear.
Latin American communities once used the cactus (Opuntia ficus indica) to filter water, says Alcantar. After boiling the edible plant, they dumped the pot water into a separate vessel containing drinking water, a practice that caused gritty particles to settle to the bottom. But this is "knowledge that