水体中石油污染土壤对鲫鱼及其肝脏抗氧化系统的毒性效应（The Toxicity of Oil Polluted Soil in Aquatic Environment on Carassius auratus and Its Hepatic Antioxidant Defense System）

在室内模拟条件下,研究了水体中不同浓度石油污染土壤暴露20d对鲫鱼(Carassius auratus)幼体死亡率和肝脏抗氧化系统的影响.结果表明,鲫鱼死亡率随其暴露浓度的变化明显分为3个部分:低浓度(0.5～5.0g·L-1)摄食死亡,中等浓度(5.0～25.0g·L-1)吸收死亡,高浓度(25.0～50.0g·L-1)胁迫死亡.1.0g·L-1浓度组死亡率最高,死亡速率最快;50.0g·L-1浓度组在暴露后期死亡速率迅速升高.鲫鱼肝脏中谷胱甘肽硫转移酶(GST)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)的活性可被显著诱导,具体表现为:在所设浓度范围内,幼体鲫鱼肝脏GST活性均受到显著激活,0.5g·L-1浓度下,GST活性被最大程度诱导,达到对照组的606%;SOD活性先升高后降低,10.0g·L-1时酶活性最强,50.0g·L-1浓度下活性被显著抑制;CAT活性于0.5g·L-1就被显著诱导,2.5g·L-1浓度是对照组的4.86倍.可以认为,鲫鱼肝脏SOD和CAT,尤其GST活性对水体中石油污染土壤较敏感,均可作为水生生态系统中石油污染存在的早期检测指标.

The Toxicity of Oil Polluted Soil in Aquatic Environment on Carassius auratus and Its Hepatic Antioxidant Defense System

Under the indoor stimulant conditions,the effect of exposure to oil polluted soil in aquatic environment for 20 days on the death rate of the larval Carassius auratus and its hepatic antioxidant system were studied.Results showed that the relationship between the death rate of Carassius auratus and the exposure dose could be divided to three parts:the death in low dose groups(0.5～5.0g·L-1)was contributed to ingestion of toxic substances;the death in medium dose groups(5.0～25.0g·L-1) was related to the permeation of toxic substances;and the death in high dose groups(25.0～50.0g·L-1) was dependent on environmental stress.The highest death rate and death velocity appeared in the 1.0g·L-1 dose group,and the death velocity increased sharply in the 50.0g·L-1 dose group in the late phase of the exposure.The activities of glutathione S-transferase(GST),superoxide dismutase(SOD) and catalase(CAT) in the hepatic system of Carassius auratus could be induced significantly.The activity of GST was the most sensitive,and it could be induced remarkably in all dose groups.Even at 0.5g·L-1,it reached the highest level(606% compared with that in the control level).The activity of SOD increased first and then decreased,and was significantly suppressed in the the 50.0g·L-1 dose group.The activity of CAT was significantly induced in 0.5g·L-1 dose group,and the highest inducement in the 2.5g·L-1 dose group was 4.86 times as much as that in the control group.It was concluded that the activities of SOD and CAT,especially GST in the hepatic system of Carassius auratus were sensitive,and they could be the early monitoring index for the presence of oil pollution in aquatic ecosystems.