毒死蜱(CPF)对河川沙塘鳢幼鱼的急性毒性

采用静水生物测试法研究了毒死蜱(CPF)对河川沙塘鳢(Odontobutis potamophila)幼鱼的急性毒性效应并进行了安全评价。设定0 mg/L、0.18 mg/L、0.36 mg/L、0.57 mg/L、0.86 mg/L和1.1 mg/L 6个CPF质量浓度梯度进行急性暴露实验,以肝超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和谷胱甘肽(GSH)含量为指标,研究CPF污染对幼鱼肝抗氧化系统的影响。结果表明,CPF浓度升高对实验鱼产生了较大毒性,24 h、48 h和96 h LC50分别为(0.296±0.019)mg/L、(0.16±0.036)mg/L和(0.052±0.003)mg/L,随着时间延长呈显著下降趋势,符合双曲线衰减模型(R=0.999 9,P<0.000 1),安全浓度为(0.014±0.003 1)mg/L;低浓度染毒条件下,CAT活性随时间变化较小,在0.57mg/L CPF染毒96 h后CAT活性达到最大值,之后随药物浓度的升高而降低,CAT活性随时间和药物浓度呈极显著变化(P<0.01);SOD活性变化与CAT相似,在时间和不同浓度CPF的共同作用下,SOD活性表现出显著差异(P<0.05);药物对GSH含量的影响不大,在0.36 mg/L以上浓度组,24 h和48 h的含量有所下降,96 h的含量则维持在较高水平,GSH含量随时间呈现极显著变化(P<0.001);由此可见,肝CAT、SOD酶活性和GSH含量作为毒理学指标能较好地评价CPF毒性效应。组织病理观察发现,CPF污染对河川沙塘鳢幼鱼的鳃、肝均造成严重损伤:鳃丝紊乱、上皮细胞增生,鳃小片肥大、充血,鳃弓软骨细胞变性、溶解;肝细胞发生实质空泡化,细胞间隙增大,胆管内皮细胞肥大隆起。

Acute toxicity of chlorpyrifos (CPF) to Odontobutis potamophila juveniles

We evaluated the acute toxicity of chlorpyrifos(CPF) to juvenile Odontobutis potamophila.Juvenile O.potamophila were exposed to 0,0.18,0.36,0.57,0.86,and 1.1 mg/L CPF in a static test.We measured SOD,CAT activity,and GSH content in liver.CPF was highly toxic with 24,48,and 96 h LC50 values of(0.296±0.019),(0.16±0.036),and(0.052±0.003) mg/L,respectively.The maximum safe concentration was(0.014±0.003 1) mg/L.The CPF LC50 decreased significantly with time and fit a hyperbolic decay model with a high R.CAT activity did not change significantly at low CPF concentrations.Both sampling time and CPF concentration had a significant effect on CAT(P<0.001) and SOD activity(P<0.05).The concentration of CPF had little effect on GSH content.There was a significant change in GSH levels over time(P<0.01).GSH levels declined after 24 and 48 h in the group administrated with 0.36 mg/L CPF but were higher after 96 h.Our results suggest that the toxic effects of CPF can be evaluated by measuring liver CAT and SOD activity and GSH content.Exposure to CPF caused sig-nificant damage to the gill and liver,characterized by gill disorder,epithelial cell proliferation,hypertrophy,and blood congestion.Furthermore the liver endothelial cells swelled and merged with one another,resulting in roughness and abnormality of the liver duct wall.Our results can be used to guide development of protocols for the safe use of CPF and the development of eco-friendly farming techniques for O.potamophila.