敌草快对藻类和溞类的急性毒性及其水中含量测定

敌草快是一种非选择性、广谱的联吡啶类触杀性除草剂,主要通过干扰植物细胞膜、破坏光合作用而快速发挥效果。为探究敌草快对水生生物的毒性,测定了该化合物对羊角月芽藻和大型溞的急性毒性,并建立了高效液相色谱法测定水中敌草快含量的方法。结果表明:检测方法在1.00×10-2~3.00×10-2mg a.i.·L-1范围内的线性相关系数为0.99995,添加回收率在90.3%~109%之间,相对标准偏差(RSD)为1.10%~10.3%,保留时间在7.2 min左右。按实测浓度和理论浓度分别计算敌草快对羊角月芽藻的72 h的半数效应浓度EyC50(72 h-EyC50),分别为3.16×10-2mg a.i.·L-1和3.32×10-2mg a.i.·L-1,均为高毒;对大型溞48 h的半数效应浓度EC50(48 h-EC50)分别为1.18×10-2mg a.i.·L-1和1.33×10-2mg a.i.·L-1,均为剧毒。

Acute Toxicity of Diquat to Pseudokirchneriella subcapitata and Daphnia magna Straus and Determination of Diquat in Water

Diquat is a non-selective herbicide and will kill a wide variety of plants on contact, which belongs to dipyridyl herbicides. It is a fast-acting herbicide that works by disrupting cell membranes and interfering with photosynthesis. In order to reveal its toxicity to aquatic organisms, its acute toxicity to Pseudokirchneriella subcapitata and Daphnia magna Straus were tested in the laboratory, as well as its true concentration in water were determined by HPLC method. The results indicated that the linear relationship coefficient is 0.99995 in the range of 1.00×10^-2-0.300 mg a.i. L^-1. The recovery for the samples is between 90.3% and 109% with the relative standard deviation (RSD) of 1.10%-10.3%. Retention time is about 7.2 min. According to the measured concentration and theoretical concentration, the 72 h- E_yC₅₀ of diquat on Pseudokirchneriella subcapitata were 3.16×10^-2 mg a.i. L^-1 and 3.32×10^-2 mg a.i. L^-1 respectively, showing high toxicity; the 48 h- EC₅₀ of diquat on Daphnia magna Straus were 1.18×10^-2 mg a.i. L^-1 and 1.33×10^-2 mg a.i. L^-1 respectively, showing high toxicity.