LOS ANGELES -- "Don't drink the water" may someday be replaced with "Don't forget your pen" as standard advice for vacationers.
Researchers have developed a battery-operated pen-shaped device for travelers and campers, as well as soldiers and victims of natural disasters, that can quickly and safely disinfect contaminated drinking water.
Unscrew the pen's cap to remove a salt pellet, drop it into a cartridge, screw the top back on, shake it then wait until the thing stops vibrating and you have a solution that can disinfect about a liter of water.
The method would replace chemical disinfectants such as chlorine or having to boil the water.
"In developing countries, the level of microbes is obviously unknown, but even if the load is high we are able to reduce the infectious loads to a rate that is not detectable," said Mark Sobsey, professor of environmental microbiology at the University of North Carolina at Chapel Hill.
He also directed a laboratory study of the device, the results of which were presented on Thursday at a meeting here of the American Society for Microbiology.
The pen, developed with funding from the Department of Defense by Miox Corp. of Albuquerque, New Mexico, even reduces levels of cryptosporidium, an intestinal parasite that is resistant to chlorine.
The device disinfects water by generating mixed oxidants, including chlorine, from a sodium chloride salt pellet.
Similar systems, on a much larger scale, are used to purify public water supplies, including that of the city of Santa Fe, New Mexico, Sobsey said.
His researchers tested the pen against microbes including bacteria like the deadly E.coli, bacterial spores, viruses, and cryptosporidium, which has been known to turn up in public water supplies.
"There was a dramatic reduction of all test bacteria and viruses within one to ten minutes. There was also extensive inactivation of cryptosporidium," explained Maren Anderson, one of the researchers.
The pen, which the researchers said is likely to retail for around $100, can be used repeatedly, with only new salt tablets and a working battery needed.
The resulting water has no chlorine smell or taste, they said, despite the fact that the electrochemical reaction produces chlorine.
"It must have something to do with the other oxidants that are produced -- there is evidence of ozone and peroxide -- but the exact reason is still being studied," Sobsey said.
The Environmental Protection Agency has approved on-site generation of oxidants as equivalent to chlorine in its ability to disinfect public water supplies, but Sobsey is hopeful that the agency will eventually make a distinction between the two methods.
He added that the disinfecting pen produces no more unwanted byproducts than the chlorine which is typically used.
The pen is currently being field-tested on a military base.
