CRYOALGOTOX - USE OF CRYOPRESERVED ALGA IN A SEMISTATIC MICROPLATE TEST

Use of cryopreserved alga Selenastrum capricornutum has been evaluated as a simple and cost-efficient procedure in a new semistatic algal ec otoxicity test. Experiments have been conducted to compare performance criteria of this method, named Cryoalgotox, versus the classic microp late test using fresh algae. Cryoalgotox 72-h 50% effective concentrat ions (EC50s) determined with Cd2+, Cu2+, Cr6+ and atrazine were more s ensitive, repeatable (low coefficients of variation), and reproducible (low time effect) than the results obtained with the classical microp late tests. The effect of storage time at -80 degrees C on the sensiti vity of the algae was assessed using cadmium as a toxic reference; it was shown that algae stored at -80 degrees C over a 3-month period gav e comparable toxicity results to those found with fresh algae.