The Toxicity Of Abamectin And Two Quaternary Ammonium Cationic Surfactants To Daphnia Magna

The aquatic invertebrate water fleas are very sensitive to pesticides and environmental contaminants chemicals entered the aquatic environment through various channels can impact the population of water flea, and cause the deterioration of water quality. In order to determine the toxicity of abamectin and two quaternary ammonium cationic surfactants to Daphnia magna, especially the biological significance of the changes of biological indicators exposed to low-concentration, so that can be predict the potential hazards of them to Daphnia magna population more accurately. In this paper, there are three indicators, which including acute toxicity, chronic toxicity and embryo toxicity, to reflect that abamectin and two quaternary ammonium cationic surfactants have influences on aquatic invertebrate Daphnia magna. The results are as follows.1. The48h-EC5o values of abamectin and two quaternary ammonium cationic surfactants to Daphnia magna were2.34x10^-4(1.74x10^-4-2.96x10^-4)a.i.mg/L,1.56x10^-2(9.75x10^-32.51x1O^-2)a.i.mg/L,1.45x10^-2(8.64x10^-3-2.38x10^-2)a.i.mg/L, respectively, belongs to highly toxicity. The EC₅₀ values decreased significantly with the increase of exposed time and the curve of dose-response relationship showed like an "S". After poisoning the swimming speed obviously slow down, the antenna beamed back up and no swing any more, the body no longer lucency and looks white, after the death drowned in the bottom of cup, several visceral of body appears shrinks.2. The21day chronic toxicity test of abamectin and two quaternary ammonium cationic surfactants to Daphnia magna showed that the offspring of frist and third brood, the total offspring, the length and the sex differentiation have been influenced significantly. In the test concentration range, the time of frist and third pregnancy, the broods and molts have no change. The sequence of all biological indicators’senstivity as follows, the offspring of the third brood> the offspring of the frist brood> the length> the total offspring> the survival rate> the sex differentiation> the time of the frist and third pregnancy=the broods and molts. After exposed in the122721days, the offspring of the frist and third brood, the total offspring, the length, the broods and molts and the sex differentiation have been affected significantly. But in the test concentration range, the time of first and third pregnancy have no change. The sequence of all biological indicators’senstivity as follows, the offspring of the third brood> the length> the total offspring> the offspring of the frist brood> the sex differentiation> the broods and molts> the survival rate> the time of the frist and third pregnancy. Compared C8-10with1227, it can prolong the time of the third pregnancy but still have no singnificant influence to the time of the first pregnancy. The sequence of all biological indicators’ senstivity as follows, the offspring of the first and third brood>the total offspring>the length> the molts> the time of the third pregnancy> the sex differentiation> the broods> the survival rate> the time of the frist pregnancy.3. The embryo toxicity test of abamectin and two quaternary ammonium cationic surfactants to Daphnia magna showed that both early embryo and late embryo have been inhibited singnificantly. The main toxic traits include larval curved or unextended shell spine and undeveloped antenna.