Bio-Technical Resources will develop a biosensor system for rapid detection of specific toxic metals and organic compounds in blood or urine. Chemical-specific biosensors are produced by fusing chemical-responsive regulatory genes and reporter lux genes, then transforming an appropriate host with the resulting fusion plasmid; biosensors emit easily measurable levels of light when exposed to samples containing a particular toxic chemical. Biosensor systems of this type, because of their inherent sensitivity, are uniquely suited for the specific and selective detection of low levels of toxic compounds. Phase I research will focus on the feasibility of adapting a mercury biosensor, previously developed for environmental monitoring, to blood and urine. The luminescent response to mercury will be quantified, and the biosensors' sensitivity, range of response, and selectivity will, be characterized. Additional effort will be directed toward ongoing development of other sensors, including sensors for arsenic, lead, and cadmium. Phase II research will develop a prototype commercial system to screen blood and urine for evidence of acute and long-term exposure to specific toxins. The advantages of this biosensor approach over those currently in use include ease of use, sensitivity, specificity, and low cost.