Keywords: 
• dispersant /
• 120 # fuel oil /
• Hemicentrotus pulcherrimus /
• antioxidant enzyme activities

Abstract: The use of dispersants is an oil spill response technique. However, effects of dispersed oil on aquatic organisms are controversial. In the present study, effects of 120 # fuel oil dispersed by dispersants on antioxidant enzyme activities of sea urchin (Hemicentrotus pulcherrimus) were investigated. The sea urchins were exposed to seawater, dispersant, water-accommodated fractions (WAFs) or chemically enhanced water-accommodated fractions (CEWAFs) for 96 h. Four antioxidant enzyme activities, that is, the activities of catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST) and glutathione peroxides (GPx), in intestine and gonad of sea urchins were measured. The results indicated that four enzyme activities increased firstly and then dropped down with increasing loading rate of oil. The maximal enzyme activities induced were significantly higher (P < 0.01) than those of seawater control group. The maximal times of four enzyme activities in intestine were higher than those in gonad in WAFs and CEWAFs groups. At the same concentrations, four enzyme activities induced by CEWAFs were higher than those induced by WAFs. There were no significant differences (P > 0.05) of four enzyme activities between seawater control group and dispersant control group.