Predicting the toxic effects of Cu and Cd on Chlamydomonas reinhardtii with a DEBtox model.

Predicting the sublethal effects of pollutants to aquatic organism is essential in realistic chemical risk assessment. However, only a few dynamics models for sublethal endpoints are available. Here, we investigated the toxic effects of the essential metal Cu and the nonessential metal Cd on Chlamydomonas reinhardtiiunder both single and combined exposure, compared the effectiveness of different effect endpoints as toxic effect factors, and developed a Dynamic Energy Budget toxicology (DEBtox) model to predict the sublethal effects of Cu and Cd on C. reinhardtii. The results showed that the chlorophyll fluorescence parameter is a better toxic effect indicator than others for short-term exposure (<24 h), while algal cell growth is preferred for long-term exposure (2-6 days). The developed DEBtox model could successfully predict single metal toxicity to C. reinhardtii, while the combined metal DEBtox model slightly overestimates the joint toxicity of Cu-Cd due to the antagonistic effect of Cu-Cd on C. reinhardtii. This study is helpful to understanding and better predictions of metal sublethal toxic effects on aquatic organisms.