OECD 201: Freshwater alga and cyanobacteria, growth inhibition test
OECD 201 is a standard freshwater algae and cyanobacteria growth inhibition test commonly used for aquatic toxicology testing. The purpose of the test is to determine the effects of a substance on the growth of freshwater microalgae and/or cyanobacteria. Exponentially growing test organisms are exposed to the test substance (at least five concentrations) in batch cultures over a period of normally 72 hours. The test endpoint is inhibition of growth, expressed as the logarithmic increase in biomass (average specific growth rate) during the exposure period.