Tel Aviv Professor's Fibers 'See' Contaminants in Real Time

Although most Americans take the safety of their drinking water for granted, that ordinary tap water could become deadly within minutes, said Prof. Abraham Katzir of Tel Aviv University's School of Physics and Astronomy.

To combat the threat of contamination due to industrial spillage, natural disaster, or sabotage, the physicist has developed a new system to monitor the safety of a building or community's water supply in real time.

Modifying special fibers developed in his Tel Aviv University lab, Katzir can detect "colors" in the infrared spectrum that distinguish between pure and contaminated water. Not visible to the naked eye, this spectrum is normally only seen by certain animals, like snakes or vampire bats, to track down prey. Connected to a commercial infrared spectrometer, the fibers serve as sensors that can detect and notify authorities immediately if a contaminant has entered a water reservoir, system, building, or pipeline.

In the lab, the fiberoptic system detected poisons such as pesticides in amounts well below the World Health Organization safety threshold. Preliminary field experiments have already been done at several European sites, and the results were reported recently in the Journal of Applied Spectroscopy.

Once in use, the sensor system would be one of the first real-time water monitors in the United States to provide protection from chemoterrorism attacks -- a threat to which U.S. water supplies are particularly susceptible. "It's unlikely that someone will poison the water supply in Afghanistan," said Katzir, "but America is in grave danger and needs to arm itself against chemical threats to its drinking water.

"With our naked eyes we can't distinguish between pure water and water that contains a small amount of alcohol or acetone. They're all clear. We can't do it even with a spectrophotometer, which measures visible colors," explains Prof. Katzir. "But we can clearly distinguish between liquids using an infrared spectrometer which can distinguish between 'colors' in the invisible infrared spectrum."

Such an instrument can be used to detect hazardous chemicals, pollutants, and threats in the water, "seeing" water in the same way as a snake does. The special fiber sensors make it possible to monitor the quality of water in a remote location, such as a lake, a river, or a pipeline, and detect trace amounts of contaminants in real time, adds Katzir. Water management executives in Florida's Everglades and officials in Germany are among those who have expressed an interest in using the technology.

"Toxic materials are readily available as pesticides or herbicides in the agriculture industry and can be harmful if consumed even in concentrations as low as few parts per million," said Katzir.

Katzir's determination to fight terrorism through science has a personal side. His father, world-renowned scientist Prof. Aharon Katzir, was assassinated by the Japanese Red Army in a terror attack in 1972. "I am trying to walk in his footsteps by doing applied research that can be a practical tool in an important battle. This system can be ready for use in less than a year."

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