BACKGROUND: Chemists have developed a powerful household water purification system that puts the cleansing power of an industrial water treatment plant into a container the size of a ketchup packet. The researchers have shown that the tiny packet, which acts as a chemical filter, can be added to highly contaminated water to dramatically reduce pathogen-induced diarrhea.
HOW IT WORKS: Called "PUR Purifier of Water," the system is manufactured by Procter & Gamble. It consists of a packet containing a grayish powder composed of a number of chemicals that can collectively remove contaminants within minutes of adding them to water. The packet is added to a large container of impure water, stirred, filtered through a cloth to remove impurities, and then allowed to sit for 20 minutes to produce clear, safe drinking water. The main active ingredients are calcium hypochlorite (bleach) and ferric sulfate. The first kills a wide range of deadly pathogens, while ferric sulfate is a particle binder: it binds to particles of dirt and disease-causing pathogens that aren't killed by the bleach. The packets can kill the water-borne pathogens that cause cholera, typhoid, and dysentery, for example, and remove toxic metals like lead, arsenic and mercury, as well as dangerous pesticides like DDT and PCB.
ADVANTAGES: The PUR packets are very efficient: a single packet can decontaminate 2-1/2 gallons of drinking water, sufficient to sustain a typical household for two to three days. Unlike large stationary purification systems, PUR packets are small and portable, enabling them to be easily used in remote locations and emergency situations. This makes them promising for boosting water safety after natural disasters, like earthquakes, floods and hurricanes, which can compromise water quality quite suddenly.
A GLOBAL CRISIS: Third world countries in particular are in need of simple, safe and effective decontamination systems. Boiling is the only readily available method, but it must be done properly, and in many parts of the world, water isn't cleaned at all. In randomized controlled trials conducted by the U.S. Center for Disease Control, the chemical packets reduced the incidence of diarrhea by 50 percent.