Field Monitor to Measure Chromium and Cobalt in Subsurface Water and Soil

Ground and surface water contamination from anthropogenic sources is an important problem that must be monitored and remediated to protect the environment and human health. Chromium and cobalt contamination of groundwater is a problem in industrialized areas, where waste from plating and other industries has been improperly disposed of or unintentionally leached into the groundwater. The DOE is involved in monitoring of a number of elements including chromium and cobalt at former nuclear weapons production sites. Groundwater and surface water contamination can cause environmental and public health problems, particularly if contamination enters a water supply. Presently, monitoring requires collection and shipment of samples for analysis in well-equipped labs with expensive instrumentation and methods requiring trained personnel. A field-deployable electroanalytical monitor may avoid these problems associated with traditional monitoring techniques, but no such commercial technology is currently available for determination of cobalt and chromium in water at ppb levels. Improved detection technology capable of on-site determination of chromium and cobalt in subsurface water and soil with simple, inexpensive electrochemical monitoring equipment will serve the DOEs interest by allowing more cost- effective monitoring and will serve the publics interest by enhancing capabilities for frequent, accurate monitoring to protect water supplies. The overall objective of the proposed program is to address subsurface water and soil monitoring needs by developing a portable, real-time electrochemical sensor for the measurement of toxic metal compounds (chromium and cobalt) in water and soil digestions/extracts, using a novel combination of an advanced electrode material with a micro-fabricated electrode geometry and a sensitive voltammetric detection algorithm for high sensitivity and low interference. Phase I will demonstrate the feasibility of the approach by detecting down to 100 ppb of each target species, chromium(III), chromium(IV), and cobalt(II), in control solutions and field samples. The Phase II program will include sensor and instrument refinements and extensive field testing to study stability, reliability, and reproducibility of the portable monitoring system. Giner will utilize a commercially available off-the-shelf (COTS) electrochemical potentiostat system, allowing the proposed work to concentrate on the crucial electrochemical detection methods, rather than hardware development. Giner is well positioned to perform the proposed feasibility study because of unique experience in multi-analyte detection in various matrices (drinking water, groundwater, surface water, and urine). The proposed sensor will present the unique challenge of application of the techniques for two new metals (Cr and Co), measurement of Cr(VI) and Cr(III) individually (speciation), detection in a complex water matrix (with other potential pollutants), and detection in soil extracts. Commercial Applications and Other Benefits: Potential commercial applications include at- home analysis of well water or groundwater and industrial self-monitoring of effluent. Potential government applications of the sensor will include water quality monitoring of public drinking water, groundwater, surface water, rivers and water quality monitoring of contaminated sites and industrial effluent for agencies such as DOE, DOD, and EPA