Combined Toxic Effect Of Copper Sulfate, Mercuric Chloride And Deltamethrin On Danio Rerio ACHE Activity

With the rapid economic development, water pollution had become a serious environmentproblem, which affected the ecological balance and stability seriously these years. Waterpollution had become a focus of attention in the scientific community today, particularly in thewater environment pollution. Currently, pesticides and heavy metals are the main pollutants inthe ecological environment. Deltamethrin was one of the typical quasi-worming polyesterpesticides, and it was widely used in forestry, agriculture and health sectors due to the relativelylow toxicity pesticides, strong efficacy, and fewer drug residues. Copper and mercury wereamong the most common heavy metal pollutions in a typical representative of the excess. Coppercould break animals and plants, especially for animals’ nervous systems. Mercuric chloride wasa highly toxic heavy metal, and it was widely distributed in the environment. It could seriouslyaffect the nervous system of animals. Effects of environmental pollutants on organisms mainlyreflected in some biological indicators among organisms, especially the changes in enzymeactivity. Danio rerio was a small size test organism, which was easy to raise with short growthcycle and strong reproductive capacity. It was widely used in ecotoxicology studies.Copper sulfate, mercuric chloride and deltamethrin were chose as experimental pollutants toDanio rerio in this study. According to Danio rerio48h median lethal concentration (48h-L50)experiment, three concentration groups (0.5TU,1TU,2TU) were selected with control. Andmixing ratio of copper and deltamethrin was10:0,7:3,5:5,3:7,0:10. Mixing ratio of mercuricchloride and deltamethrin was10:0,7:3,5:5,3:7,0:10. Measurement and analysis of the AChEactive in the different concentrations variation of pollutants were carried out after eachexperiment. The results showed that:1.48h acute toxicity test indicated that the (48h-LC50) of copper sulfate, mercuric chlorideand deltamethrin on Danio rerio were1282.26μg/L、127.53ug/L and5.32μg/L, respectively.Deltamethrin was rank poison to Danio rerio, mercuric chloride was highly toxic, and copper sulfate was moderately toxic poison. Dose and mortality of Danio rerio had a strong relationshipwith the three chemicals, and the larger the drug concentration, the higher the Danio reriomortality. Mortality and medicines concentration were positively correlated. The behavior ofDanio rerio showed significant changes at the individual level.2. Copper sulfate, mercuric chloride and deltamethrin inhibited AChE activity in Daniorerio. Overall, the toxic effects of the combined exposure of copper sulfate, mercuric chlorideand deltamethrin were decided by both exposure time and chemical concentrations. AChEactivity was inhibited with this order:0.5TU<1TU<2TU. The activity of AChE in the body hadan obvious decreasing trend with the exposure time. But sometime, the AChE activity had arebound phenomenon in the body of Danio rerio, maybe it is an adaptive and adjustmentprocess for external environment.3. The results of this study showed that joint toxic effects of different chemicals to testorganisms were complicated. Though there was an obviously relationship between chemicalconcentration and test organisms, it was decided by plenty of environmental factors includingdifferent organisms, chemicals, exposure time, and exposure ratio. Chemical pollution wouldinduce toxicity effects with different mechanisms, which suggested some difference phenomenonto different biomarker. Overall, the AChE activity in danio rerio was consistent with biologystage-by-stage model.