Abstract
The EC50 value of several alkylphenols (APs) on the swimming velocity of unicellular green algae Chlamydomonas reinhardtii was measured and its relationship with the octanol⁄water partition coefficient (Pow) of APs was investigated. To clarify the sensitivity of C. reinhardtii to APs, the EC50 value was compared with that for crustacea Daphnia magna, a standard species for motility toxicology tests. As a result, there is a strong correlation (r=0.96) between the log Pow of APs and the log EC50 value for C. reinhardtii. The log EC50 value for C. reinhardtii strongly correlated (r=0.98) with that for D. magna and the sensitivities of C. reinhardtii and D. magna were almost equivalent when the log Pow of APs were large. These results confirm the reliability of the toxic evaluation of APs from the endpoint of the swimming velocity reduction test using C. reinhardtii. This method requires only 1 hour for evaluation, enabling a rapid and convenient bioassay for testing the acute toxicity of environmental pollutants in waters.
