Genomics, the global genetic analysis of organisms, simultaneously reports both specific and holistic assessments of biological systems. Genomic approaches are therefore ideally suited for the assessment of potential impacts of chemicals on ecosystems and the environment. To date, however, genomics infrastructures have not been developed for any of the commonly used and accepted ecotox/environmental monitoring organisms. Yet environmental and ecosystem toxicity has both direct and indirect impact on human health. In this proposal we will test the feasibility of developing and using microarrays for the common environmental sentinel organisms. Specifically, in this Phase I work we will construct a pilot array for Daphnia pulex. Developing this Daphnia pilot array will test feasibility of 1) developing reasonably comprehensive arrays in Phase II, 2) identifying toxic chemicals based on their expression signature, and 3) gauging chemical concentration and dose response based on expression changes. We will test the response of the arrays to the EPA?s 12 persistent bio-accumulative toxins (PBT?s). If this work proves feasibility, Phase II will involve development of a reasonably comprehensive Daphnia array and beginning arrays for fathead minnow, duckweed, and green algae. PROPOSED COMMERCIAL APPLICATION: Eon will develop and market DNA microarray-based tests for rapid and economical assessment of a chemical or effluent sample's potential toxicity to ecosystems. These tests will be sold to chemical industry and regulatory agency customers. Chemical companies using our technology will reduce time to market and cradle to grave costs. To regulatory concerns, Eon will provide a far more detailed and useful picture of chemical impacts.