Assessing the ecotoxicity of vinyl chloride using green alga P. subcapitata, nematode C. elegans, and the SOS chromotest in a closed system without headspace

The ecotoxicity of vinyl chloride (VC) was evaluated using green alga, nematode, and the SOS chromotest. The green alga and nematode tested were Pseudokirchneriella subcapitata, and Caenorhabditis elegans, respectively. Because of the tendency of VC to escape from an aqueous exposure medium to the air phase, all tests in the present study were performed in a closed system without headspace to minimize the losses of VC. Previous studies on VC toxicity were performed in an open system or closed system with headspace. VC inhibits the growth of P. subcapitata. The 48-h IC50 value for P. subcapitata exposed to VC was calculated to be 5.15 mg/L. The survival of C. elegans was not influenced at concentrations of up to 60 mg/L; however, VC has an adverse effect on the reproduction of C. elegans. In a stress-related gene expression test using C. elegans, a significant and concentration-dependent expression of heat shock protein 16.2 was observed, indicating that VC induces the stress of C. elegans at the genetic level. The results of the SOS chromotest using Escherichia coli PQ37 showed an IFmax value of 1.11, indicating that VC is not genotoxic. The present study demonstrated that VC has an adverse effect on the algal growth and reproductive and genetic levels of C. elegans. A closed system without headspace is an effective method of testing the aquatic toxicity of volatile organic compounds such as VC.