Toxicity testing of highly volatile chemicals with green algae : A new assay.

A gas-tight system for toxicity testing of highly volatile chemicals with the green algaChlamydomonas reinhardtii was developed. The procedure permits maintenance of constant and defined concentrations of the tested compounds in the vessels. To ensure sufficient CO2-supply, new bipartite test vessels were used. These vessels allowed spatial separation of a HCO3-/CO 3 (2-) buffer used for CO2 supply and the alga culture to avoid growth inhibition due to ionic strength. Several volatile chlorinated hydrocarbons have been tested. Their EC10 values were several orders of magnitude lower than those obtained with open test systems.