石油烃、Cu2+对沙蚕的毒性效应及对其抗氧化酶系统的影响

在实验室模拟条件下,研究了石油烃和不同浓度的Cu²⁺对沙蚕(Nereis diversicolor)种群的毒性效应及对其抗氧化酶系统活性的影响.结果表明:石油烃和Cu²⁺对沙蚕均表现出较强的毒性,暴露3d后,其LD₅₀值分别为117.5μL·L^-1和864.0μg·L^-1.Cu²⁺单因子污染暴露5d后,沙蚕体内过氧化物酶(POD)的活性受到显著影响,表现出先受到抑制后缓慢增加的趋势,超氧化物歧化酶(SOD)的活性也发生显著变化,其变化趋势为先被诱导而后抑制.石油烃以其约为半致死剂量水平单因子暴露5d后,POD的活性并未被显著诱导,SOD的活性则低于对照组.在石油烃与Cu²⁺复合污染的条件下,暴露5d后沙蚕体内POD和SOD活性表现出相同的变化趋势,即先下降后上升.通过比较,还发现沙蚕体内SOD的活性变化更能灵敏地反映出污染物对沙蚕的毒性作用.

Toxic Effects of Petroleum Hydrocarbons and Copper on Polychaete Nereis diversicolor and on Its Antioxidant Enzyme Systems

Under the condition of the laboratory simulation, the toxic effects of petroleum hydrocarbons and various concentrations of copper (Cu2+) on the polychaete Nereis diversicolor and on its antioxidant enzyme defense systems were examined. The results indicate that both petroleum hydrocarbons and CU2+ have high toxicity to the polychaete. After a 3-day exposure to petroleum hydrocarbons and Cu2+, the value of LD50 was 117.5 microL x L(-1) and 864.0 microg x L(-1), respectively. The activities of peroxidase (POD) and superoxide dismutase (SOD) were influenced significantly through a 5-day exposure to single pollution of Cu2+. The activity of POD was inhibited at first and then enhanced gradually; on the contrary, the activity of SOD showed a tendency of induction firstly and then inhibition. After exposed to petroleum hydrocarbons at the concentration of the value of LD50 for 5 days, POD activity of the polychaete was not significantly induced, and the activity of SOD was lower than that of control. A 5-day exposure to the joint-pollution of petroleum hydrocarbons and Cu2+ could bring out a decrease in the activities of POD and SOD firstly and then an increase. The changes in the activity of SOD can better reflect the toxic effects of pollutants on the polychaete.