The electronic system, which consists of a miniature sensor array packaged in a weatherproof housing, "can be put directly underground - in ground water or soils where the humidity reaches nearly 100 percent - and detect toxic chemicals at the site without taking samples to the lab," researcher Cliff Ho reports. "It has the capability of detecting in real time undesirable chemicals being pumped into the water supply, accidentally or intentionally. It will be able to monitor sites containing toxic chemical spills, leaking underground storage tanks and chemical waste dumps, potentially saving millions of dollars a year in the process."

Traditional monitoring methods for contaminated sites usually involve physically collecting water, gas or soil specimens at the location and taking them to a laboratory for analysis. This can become extremely expensive, with each sample analysis costing between $100 to $1,000. In addition, the integrity of off-site analysis can be compromised during sample collection, transport and storage.

The monitoring system, developed by Ho and colleague Bob Hughes, is designed to be left at the site. It would send back information in real time on solvents present and their concentrations to a data collection station where information would be downloaded and analyzed. Telemetry methods also can transmit data wirelessly from remote stations to a computer that would upload information to an interactive Web site, providing immediate access to authorized individuals anywhere in the country.

The heart of the device is an array of differing miniature sensors that can detect volatile organic compounds (VOCs). The array of differing sensors can be used to identify different VOCs by comparing the resulting chemical signatures with those of known samples. The way the sensors are packaged allows the device to be placed in water or underground.

"Over the next few years I expect we will see this invention being applied to DOE sites that require monitoring, remediation, and/or long-term stewardship of contaminated sites, which currently spend millions of dollars for off-site analysis of manual samples," Ho says. "This device can also be applied to numerous commercial sites and applications, such as gas stations, which include more than two million underground storage tanks that require monitoring to satisfy Environmental Protection Agency requirements.