Abstract: Objective To study the influence of nonylphenol on CAT and T-SOD enzyme activities in loach liver tissue. Methods The loaches were exposed in different concentration of nonylphenol. The concentration of nonylphenol were 50，200，500，1 000 μ g/L. Determined the activities of T-SOD and CAT after 6 hours. Results Low concentration of nonylphenol has an inducing effect on the activities of T-SOD and CAT in loach liver tissue, as the concentration of nonylphenol increased, the activities of CAT and T-SOD was restrained. Conclusion The concentration of nonylphenol in water is direct related to the CAT and T-SOD activities in the liver tissue of loach, as concentration of nonylphenol increasing, the CAT and T-SOD activities are all expressed in an inducing-repressing manner. The CAT and T-SOD activities have indicative function for early pollution of nonylphenol.

Key words: nonylphenol, loach, CAT, T-SOD, liver tissue