Abstract
A multispecies toxicity test is described that uses indigenous microorganisms. The test is suitable for both laboratory and field, is inexpensive, replicates easily, and uses extremely inexpensive materials. An additional advantage is the use of an important ecological rate process as an end point; therefore the test is superior to test using lethality as an end point. The test can be carried out using organisms collected from a site of interest or from a specific ecological resource area. Site-specific or synthetic dilution water may be used. The major drawback is a requirement for significant taxonomic ability. However, more general chemical measures such as ATP biomass, chlorophyll biomass, or heterotrophic index may substitute for species identification. Although this test has been used in a variety of freshwater ecosystems in the United States and has been validated to a limited degree in the People's Republic of China, a wider data base is required before it can be generally used.
