ABSTRACT
Protozoa are attractive organisms for toxicological studies, because they have short life cycles, are in intimate contact with the aquatic environment, and are relatively easy to culture and handle. This chapter describes early and more recent studies by the laboratory group on developing a chemoattraction inhibition assay with ciliates. Using a marine and a freshwater species of ciliate, Berk and Mills examined several factors which may affect results of the chemoattraction inhibition test. The chemoattraction inhibition test can be used with additional treatments to determine whether the relatively short exposures to toxicants can be diminished or eliminated by removing the test organisms from the toxicants. During development of the chemoattraction assay Roberts and Berk also compared the results with those of a 24-h mortality test on the same organisms. The chapter recommends that osmolality be monitored if possible at various stages of the test preparation.
