Sublethal Toxic Effects and Induction of gGutathione S-transferase by Short-Chain Chlorinated Paraffins (SCCPs) and C-12 alkane (dodecane) in Xenopus laevis Frog Embryos

Bur˘‰kova B., L. Blaha, D. Vr‰kova, K. ·imkova, B. Mar‰alek: Sublethal Toxic Effects and Induction of Gutathione S-transferase by Short chain Chlorinated Paraffins (SCCPs) and C-12 alkane (dodecane) in Xenopus laevis Frog Embryos. Acta Vet. Brno 2006: 75: 115-122. Short chain chlorinated paraffins (SCCPs) are important industrial chemicals with high persistence in the environment but poorly characterized ecotoxicological effects. We studied embryotoxic effects of commercial mixture of SCCP (carbon length C-12, 56% of chlorine; CP5612) and non-chlorinated n-alkane (dodecane, C-12) in the 96h Frog Embryo Teratogenesis Assay – Xenopus (FETAX). Only weak lethal effects were observed for both substances (the highest tested concentration 500 mg/L of both chemicals caused up to 11% mortality). On the other hand, we observed developmental malformations and reduced embryo growth at 5 mg/l and higher concentrations. However, the effects were not related to chlorination pattern as both SCCPs and dodecane induced qualitatively similar effects. SCCPs also significantly induced phase II detoxification enzyme glutathione S-transferase (GST) in Xenopus laevis embryos even at 0.5 mg/L, and this biomarker might be used as another early warning of chronic toxic effects. Our results newly indicate significant developmental toxicity of both SCCPs and n-dodecane to aquatic organisms along with inductions of specific biochemical toxicity mechanisms.