Components of the mixed aerosols generated during military training are known to be of toxicological and/or ecological significance. There are few studies, however, quantifying mixed aerosol effects on ecosystems. Prompted by our finding that one or more of the compounds in the mixed aerosols commonly encountered in military training areas showed mutagenic effects in several species, a multiyear effort is evaluating the use of ecotoxicity testing methods to assess mixed aerosol ecological impacts. Selection of test methods for ecoepidemiology begins with the identification of the data required to meet defined environmental quality objectives. The data requirements are then matched with appropriate test methods, and testing results are related to important ecological effects resulting from aerosol exposure. The critical element of test system selection is to ensure that toxicity testing results relate to important ecological effects. The procedures developed for identifying test methods to assess mixed aerosols are also applicable to a range of environmental contaminants regulated by air, water, and solid waste regulations.