Progress in an ecotoxicological standard protocol with protozoa: Results from a pilot ringtest with Tetrahymena pyriformis

The aim of this project was to develop a standardized multigeneration growth inhibition test protocol to assess the sublethal effects of industrial chemicals and pesticides on protozoans. The inclusion of a test with protozoa would be an ecologically relevant supplement to the existing basic set in aquatic toxicity testing. The different aspects evaluated in the pilot ring study include: two media, two volumes, two end points and two different methods to measure the cell density. Taking into account the aim to develop a simple, sensitive, reproducible and cost effective test, recommendations are made for a standardized protocol.