"Dealing with arsenic contamination of drinking water in the developing world requires simple technology based on locally available materials," said study leader Tsanangurayi Tongesayi, Ph.D., professor of analytical and environmental chemistry at Monmouth University, West Long Branch, N.J. "Our process uses pieces of plastic water, soda pop and other beverage bottles. Coat the pieces with cysteine -- that's an amino acid found in dietary supplements and foods -- and stir the plastic in arsenic-contaminated water. This works like a magnet. The cysteine binds up the arsenic. Remove the plastic and you have drinkable water."
Tongesayi described laboratory tests of the plastic bottle arsenic removal method on water containing 20 parts per billion (ppb) of arsenic, which is two times the safe standard set by the U.S. Environmental Protection Agency for drinking water. It produced drinkable water with 0.2 ppb of arsenic that more than meets the federal standard.
Link -via Fast Company | Photo Credit: Warrenski
I'm guessing that because the arsenic would bind with the cysteine, it'd take some deliberate work to release the arsenic.