Abstract: Atrazine is one of the most widely used herbicides in China and worldwide.Being highly persistent,it exists for long in surface and ground waterbodies,threatening nontarget organisms,such as fish,and contaminating drinking water for human beings.An experiment was conducted on Carassius auratus to study effect of atrazine on glutathione S-transferases(GSTs) activity.Groups of fish were exposed to atrazine varying in concentration,i.e.0,0.1,0.5,1.0,5.0 and 10.0 mg·L~(-1),respectively.The GSTs activities in liver,kidney and muscle of fish exposed to 1.0 and 10.0 mg·L^-1 were measured after Day 3,6,10,14,19 and 24,respectively,to study time-response relationship between atrazine and GSTs activities in these organs.At the end of the experiment(24 days),GSTs activities in the three organs of fish in all treatments were evaluated to explore dose-response relationships between atrazine and SOD activities in these organs.Results indicate that atrazine had strong influences on GSTs activities in the three organs;long exposure(24 days) to atrazine induced activities of GSTs in liver and muscle,with a maximum rate being 110.81% and 32.54%,respectively;and their dose-response relationship was significant,when the concentration ranged from 0.1 to 5.0 mg·L^-1 and from 1.0 to 10.0 mg·L^-1,respectively.Long exposure(24 days),however,inhibited renal GSTs activities,with a maximum rate being 14.42%,and their dose-response relationship was distinct in all the treatments in the experiment.When the fish was exposed to atrazine,10.0 mg·L^-1 in concentration,on Day 6-14,the time-response relationships existed between atrazine and activities of GSTs in liver and muscle,but did not in any organs in any other treatments.

Key words: sub-lethality, atrazine, Carassius auratus, glutathione S-transferases