Research On The Toxicity And Safety Of Paraquat

Paraquat(1,1'-dimethyl-4,4'-bipyridylium) was originally developed in English in 1995 as a bipyridylium herbicide. Because of its good effect of weeding, paraquat is wide use in more than 120 countries in the world, and it plays an important role in agriculture. From 70s, its high toxicity has been reported in animals as well as in human, and we have no effective antidote. Once someone poisoned, the life will be in danger. It already confirmed that paraquat is a stable compound, it has long biological half-life in the soil, and can easily absorbed by organism. Therefore with the increased usage of paraquat, the remaining in the environment and food material will bring tremendous influence to the mankind and the environment.The purpose of the study is going to comprehend the toxicity and the mechanism of paraquat in human being. We can provide more information for treatment, formulating the standard of remanet. We also can offer the referential control scheme of food security for crop that use paraquat as its herbicide.As a part task of a project from Science and Technology Department of Jilin Province"Study on toxicity of bipyridylium herbicide in fetal circulatory system", the paper mainly completed tasks as below and corresponding conclusions were got:1. The LD₅₀ of paraquat is 77.5053mg/kg. According to pesticide classify standard, paraquat is middle toxicity compound. It can affect the digestive system and respiratory system of animals, even death. The toxicity is especially marked in the lung, and the lung is the target organ.2. In the accumulative toxicity test, there were no animal dead of 1/20 LD₅₀ group, and each of the rest groups has dead animals. And there was dose-response relationship between them, paraquat is mid-accumulative.3. In the sub-chronic toxicity test,we got that paraquat has effect on the weight of male rat at high dose and has no effect on female. The study concluded that paraquat has certain effect on liver and lung through the study on organ index and blood biochemical index.and checking of pathology and histology.4. Paraquat can raise the rate of micronucleus of born marrow cell in rat, the test has statistics sense compared with control group. During a certain dose scope, the rate of micronucleus will raise follow the dose's increase. And there was dose-response relationship between them. The result illustrates that paraquat can make chromosome cracked during body cell fission.5. Paraquat at the low dose of 7mg/kg, can induce contraction of ductus arteriosus of rat fetus, it illustrate that paraquat can pass the placenta.6. The critical contraction time of ductus arteriosus of fetus induced by paraquat is after 19 2/3 day,and we can get that the time of paraquat affect on fetal ductus arteriosus is the first half of 19th day. 7. The highest consistency of paraquat appeared after 1 hour of injection in the pregnant rat's blood, and ended in 6 hour. The highest consistency of paraquat appeared after 2 hour of injection in the fetal blood, ended in 24h, the consistency of paraquat present the tend of descending.