A new Toxkit microbiotest with the protozoan ciliate Tetrahymena

Abstract

Culture free microbiotests with organisms from different trophic and functional levels, e.g. bacteria, algae, rotifers and crustaceans, are presently available. This paper presents the status quo and general design of a new, ready to use multi-generation microbiotest with the standard ciliate Tetrahymena, a, representative from a further ecologically relevant group—the protozoa. The latter constitute a major link between bacteria and metazoa, playing a key role in the natural microbial loop and as consumers in the artificial system of waste water treatment.

Based on a heterogeneous set of chemicals, toxicological results with 2 Tetrahymena species, T. pyriformis and T. thermophila, reveal a highly significant correlation (r=0.928, n=52) and nearly equal susceptibility of species. Comparisons of toxicological literature data from the International Uniform ChemicaL Information Database (IUCLID) indicate a similar toxic response even for distant ciliate relatives. Data from IUCLID also reveal that ciliate toxicity data are supplementary to those of the standard activated sludge respiration inhibition. Ciliate tests could hence serve as a powerful tool for the prediction of possible hazards to sewage treatment processes.