Application of a Tetrahymena pyriformis bioassay system for the rapid detection of toxic substances in wastewaters

A bioassay technique based upon the respiratory response of Tetrahymena pyriformis to intoxication, which gives results within 10 min, was used to evaluate the quality of a number of effluents from three wastewater treatment plants in the PretoriaJohannesburg area. Toxic activity was detected in both treated and untreated wastewater effluent. The technique was shown to be sufficiently sensitive to monitor toxicity in raw and treated wastewater effluent, and to evaluate the efficiency of the various treatment stages to remove toxicants from raw waters.