An inexpensive apparatus for toxicity screening

An inexpensive apparatus was fabricated to monitor and record changes in the motility patterns of small aquatic invertebrates, such as Artemia salina and Daphnia magna, during acute toxicity tests. Within hours of exposure to a range toxicant concentrations the motility patterns change in a way that predicts the EC50. The work to date suggests there is a correlation between the EC50 following a 60 hour exposure, and motility data collected within the first 40 minutes of the test. The apparatus may be useful to speed range finding tests and for shortening the duration of acute toxicity tests of an effluent or receiving water. The apparatus may also be used to quantify erratic swimming in surviving organisms when a test is terminated.