Penn State engineers have recently developed an underwater sensor system that could help protect American citizens by detecting toxic chemicals that terrorists might use to contaminate the drinking supply.

"It is the type of technology we would be very well off having in use, and it could be put into use soon," said Craig A. Grimes, associate professor of electrical engineering and materials science and engineering.

The system can automatically monitor streams, lakes, reservoirs and other bodies of water for pollutants and other potentially harmful substances. It uses a series of nodes set up underwater, distributed across the body of water so that the composition can be monitored in many different locations.

The nodes are programmed to collect information about chemical levels in the water, using sensors that then send the data to an uplink node floating on the water's surface. The uplink node then transmits this data via acoustic waves to a central command computer on land.

Bill Dreschel (graduate-electrical engineering), a researcher in Grimes' lab, helped to design the initial nodes and put the whole system together.

"The general idea is to have a constant monitoring system for bodies of clean water," he said.

Keat G. Ong, the chief scientist at SenTech Corporation, 200 Innovation Blvd., helped to develop the individual sensors. Once the system was assembled, the researchers tested it at McCoy Natatorium.

There are many benefits to using this system, Grimes said.

"The water sampling techniques that are in use today are the same as the ones used 50 years ago -- someone puts water in a jar and takes it back to a lab," he said. But he said the new sensor system would be much more effective because the water would be sampled continuously and from many different points. Also, the process would all be done automatically by computers.

He said the system was created to conserve power.

"Every node operates in low-power or 'sleep' mode. Through the power of a microprocessor and the appropriate software, we can program the nodes to [collect information] periodically, such as every 10 minutes or every hour," he said. "If a node detects something in the water, like a poison, the software 'wakes' it up, and it will sample the water more frequently and also alert the other nodes."

Grimes said the project started a couple of years ago, when reports came out that analysis of the water composition of lakes located downstream from water processing plants revealed that the lakes were "a soup of hormones and antibiotics." But the new technology is of particular interest to Americans today due to the war with Iraq and terrorist threats.

Ong said most reservoirs can be accessed by the public, and it would be easy for terrorists to contaminate them and devastate entire areas at a time. The only ways to protect these bodies of water would be to close them off to the public or to shut them down entirely -- unless the new sensor system is implemented.

"If we put the sensors into the lakes, all the information about the water would be sent to a central command post," he said. "It saves money, because we don't have to hire as many people [to sample the water], and it will make our reservoirs safer, because right now they are not protected."

Grimes said he thinks the government will take action soon to incorporate the new technology into homeland security plans.

"Issues of terrorism make this a timely [development]," Grimes said. He mentioned the arrests of four suspected terrorists near Paris last December, who allegedly were planning to contaminate the area's drinking supply with toxic chemicals.

"Had those people succeeded, it would have changed the world," he said. "The time is right for this technology to be put into use."