Engineers from the University of Wisconsin, Milwaukee have developed a sensor with a graphene-based nanomaterial that can immediately detect the presence of lead and other heavy metals.

The technology can be used for one-time testing of lead in tap water through a handheld device. The sensor can also be integrated into water meters and purifiers, with the goal of continuous monitoring to prevent exposure to lead that could be introduced between the water treatment plant and the home.

Lead can enter drinking water when service pipes that contain lead corrode. Image credit: University of Wisconsin, Milwaukee/National Science Foundation. "By putting graphene sheets in an electronic circuit, we can measure its resistance," says Junhong Chen, professor of materials science and engineering. "When you have a contaminant, it binds to the surface of the graphene and its conductivity will change."

Chen's team is now working with several manufacturers, including A.O. Smith Corporation, to put the sensor into use.

"Point-of-use filtration can really take care of the contaminants that are introduced from the water treatment plant to the home," says Bob Heideman, senior vice president of corporate technology at A.O. Smith. "Dr. Chen's work gives us the ability to ensure that the contaminant is being removed by our filtration products."

In addition to lead, the technology can be adapted to test for other chemical signatures, such as mercury and arsenic, as well as E. coli bacteria.