Several US agencies and regulators require low-cost chemical sensors for detecting and monitoring environmental clean-up, remediation, and decommissioning processes where groundwater may be contaminated. The sensors must be capable of detecting contaminants in the sub-surface groundwater and must be compatible with use in a range of environments. Most significantly, these customers require a low-cost alternative to its current expensive and labor intensive methods, namely using mobile laboratories. The project will result in the innovative use of low-cost sensor systems that will be capable of detecting and monitoring for dense non-aqueous phase liquids in the subsurface and groundwater, unattended, and in real- time from within a push-probe, using a chemicapacitor array and miniature preconcentrator. Seacoast's Phase I research will focus on developing the sensor array, demonstrating sensitivity to chlorinated hydrocarbons at relevant concentrations, and field tests in actual contaminated sites. The ultimate goal is to provide the DOD, DOE, NIEHS and other agencies with a method to map and track subsurface contamination plumes in real-time without requiring an operator. The systems will have MEMS microcapacitor sensor arrays that can monitor for leaks of toxic chemicals, contaminants from wastes, and changes in groundwater streams. A preconcentrator collects the contaminants and releases them to a microsensor array. The sensor arrays are filled with several chemoselective polymers whose dielectric permittivity changes when exposed to different vapors, creating a fingerprint response for each chemical. An array of differently responding sensors and pattern recognition can thereby compensate for changes in humidity, temperature, and composition. These low-power systems can be left unattended and transmit data wirelessly or through USB to a central location. The most important application to public health and safety is unattended monitoring of drinking water, water treatment processes, and water sources. The potential commercial markets include building chemical process monitoring and control, toxic vapor leak detection, industrial process control, and industrial health and safety. Transitioning the developed prototype to other markets where worker and public health, environmental health and regulatory compliance will be investigated to reduce the financial risks and broaden the acceptance of the technology.
This proposal will describe a potential method to specifically address the need for detecting groundwater contaminants and long-term monitoring of contaminated sites, by providing an unattended sensor system that tracks contamination in real-time and transmits contaminant concentrations. Such a system would be used in tandem with other methods, to provide comprehensive contamination management at DOE, DOD, and Superfund sites where ground and water clean-up projects are already underway. The proposed work will focus on detection of chlorinated hydrocarbons, which are described as among the most common pollutants in groundwater and soils at DOE sites.
| Hobson, Stephen T; Cemalovic, Sabina; Patel, Sanjay V (2012) Preconcentration and detection of chlorinated organic compounds and benzene. Analyst 137:1284-9 |
