通过多阶段暴露试验评价嘧菌酯对斑马鱼的急性毒性与发育毒性

嘧菌酯作为最畅销的甲氧丙烯酸酯类杀菌剂,是防治水稻病害的常用农药,其对水生生态环境的负面效应值得重视.为研究嘧菌酯对水生生物的危害,进行多阶段(成鱼、仔鱼、胚胎)斑马鱼毒性试验,分析了嘧菌酯对鱼类的急性毒性,同时,通过6 d胚胎发育试验,研究了嘧菌酯对鱼类早期发育阶段的影响.结果表明,斑马鱼3个生命阶段对嘧菌酯的敏感性(以96 h-LC50(致死中浓度)表示)顺序为:仔鱼(0.39 mg·L~(-1))胚胎(0.61 mg·L~(-1))成鱼(1.37 mg·L~(-1)).6 d胚胎发育试验结果发现,嘧菌酯可诱导斑马鱼胚胎出现一系列不良症状,包括孵化率下降、心率异常、生长抑制和心包水肿等.0.25 mg·L~(-1)的嘧菌酯可显著促进斑马鱼胚胎自主运动和心率,并能明显抑制孵化仔鱼的体长.0.6 mg·L~(-1)及更高浓度的嘧菌酯可明显抑制斑马鱼胚胎眼睛、体节、尾部和心脏的发育.研究显示,嘧菌酯对斑马鱼多个生命阶段均具有一定毒性,但对早期生命阶段毒性更强,因此,其对鱼类早期生命阶段的影响值得重视.

Evaluation of acute and developmental toxicity of azoxystrobin on zebrafish via multiple life stage assays

Azoxystrobin is the most salable strobilurin fungicide and is widely used for control of rice disease. Therefore, its negative effects on aquatic ecosystem need to be concerned. To evaluate the risk of azoxystrobin to aquatic organisms, the acute toxicity of azoxystrobin to fish was assessed via multiple stage (embryo, larvae and adult) zebrafish assays. In addition, a six-day embryonic exposure was also carried out to investigate the developmental effect of azoxystrobin. This study concluded that the acute toxicity of azoxystrobin to the three phases of zebrafish were larvae (LC₅₀:0.39 mg·L^-1) > embryo (LC₅₀:0.61 mg·L^-1) > adult fish (LC₅₀:1.37 mg·L^-1). The embryonic test indicated that azoxystrobin could induce a large suite of developmental abnormities, including hatching inhibition, heart rate alteration, growth inhibition and pericardium edema. 0.25 mg·L^-1 azoxystrobin apparently induced the spontaneous movement (24 hpf) as well as heart rate (96 hpf) of zebrafish embryos and reduced the body length of hatched larvae at 96 hpf. In addition, 0.6 mg·L^-1 or higher azoxystrobin could significantly inhibit the development of eyes, tail, somite and heart. This work implicated that azoxystrobin had lethal ability to zebrafish during all three test periods, and early life stage was more sensitive towards azoxystrobin. Attention needs to be paid on the effect of azoxystrobin on fish during early life stage.