Abstract: The characteristics of toxic organics in typical petrochemical wastewater and different polar components were explored. And the biotoxicity effects of petrochemical wastewater were evaluated combined with acute biotoxicity and genotoxicity. According to gas chromatography-mass spectrometry（GC-MS） analysis, the strong-polar organics in petrochemical wastewater mainly included nitrogen-containing heterocycles and amines, and the non-polar organics mainly included phenols and alkanes. The toxic unit (TU) and tail DNA percentage (Tail DNA %) of petrochemical wastewater were 10.49 and 98.01, respectively. It indicated that the petrochemical wastewater has strong acute biotoxicity and genotoxicity. The TU of strong-polar component was 19.88, which was the key organics inducing the acute biotoxicity of petrochemical wastewater. The Tail DNA % of the non-polar component was 90.07, which was the main organics inducing the genotoxicity of petrochemical wastewater. According to oxidative stress analysis, the reactive oxygen species (ROS) increase rate caused by petrochemical wastewater was 5.32%, indicating that petrochemical wastewater can induce oxidative stress, thereby inducing the acute biotoxicity and genotoxicity on Tetrahymena thermophilecells. Based on the above results, the biotoxicity effects of petrochemical wastewater were clarified and its potential main toxic organics were identified, thus providing theoretical guidance for priority control of toxic organics in petrochemical wastewater and protection of water environment safety.

Key words: petrochemical wastewater, polar component, acute biotoxicity, genotoxicity, toxic organics