Prickly pear purifies water

A water filtering process based on the nopal cactus or prickly pear found throughout Mexico, which is being designed by the chemical engineer Norma Alcantar at the University of South Florida in Tampa, USA, will be tested in Temamatla, Mexico in the summer of 2006, according to Science News (17 September, 2005, Vol. 168). The process may provide a simple solution to purify groundwater contaminated with arsenic, sand and other solids.

Alcantar reports that Latin American communities used the cactus to filter water, but this traditional practice has almost completely disappeared. Drinking water in many Mexican cities is laced with arsenic, ions, heavy metals, and bacteria, which may be precipitated out by using the cactus’ mucilage, a “thick, gooey substance that enables the plant to store large amounts of water.” Research conducted by Alcantar and her group will attempt to determine the optimal mucilage dosage to purify water.