Study On The Residual Detection Of Typical Organophosphorus Pesticides In Inland River Of Hangzhou

Organophosphorus pesticides（OPPs）is one of the most widely used pesticides in the world because of its high efficiency,easy degradation and low cost and so on.OPPs can be transported to environmental water through the surface runoff during the production and usage of OPPs,which possesses the risk to human health and ecosystems.Therefore,it is in high demand to monitor the residual concentration of OPPs in the environmental waters.At present,the pretreatment methods of water samples for OPPs analysis feature the disadvantages,such as complex operation,large amount of organic solvent,long time consuming,and so on.Furthermore,there are few studies on the characterization of OPPs residues and health risk assessment for the inland water in China.As a result,in this thesis,a rapid liquid-liquid microextraction technique（LLME）was established for the ultra-high performance liquid chromatography（UPLC）to characterize the OPPs residues in inland river of Hangzhou as well as the health risk.Finally,based on a stand-alone positive photoionization ion mobility spectrometry,a rapid method for OPPs analysis was developed.The specific research contents are as follows:（1）A method for simultaneous determination of seven OPPs in water was established by UPLC in the combination of rapid LLME method.The chromatographic conditions of UPLC,as well as the pretreatment conditions such as the type and volume of extraction solvent,the extraction times,the pH,the amount of salt added and the way of dispersion were systematically optimized.The feasibility of seven OPPs analysis methods is demonstrated,the R² of calibration curves in a range of 0.9927 to 0.9984.The method limit of detection（LOD）for tested OPPs ranged from 0.04μg/L to 0.15μg/L.The recoveries were in a range of 75.3%to 112.6%.The relative standard deviation（RSD）for five repeated trails was lower than 14.9%.Thus,this proposed method met the requirements for the detection of trace OPPs in the environment waters.（2）Based on the established LLME-UPLC method,the residues of seven OPPs in Shangtang River,Grand Canal and three drinking water sources were characterized.The results showed that seven OPPs were all detectable in different degrees.The highest detectable concentrations were in a range of 0.06 ug/L to 0.54 ug/L,which were lower than the standard limits in the environmental quality standard of surface water in China（GB3838-2002）.The highest detectable concentration,the sum of concentration and detection rate of seven OPPs in Shangtang River in September were higher than those in other basins in the same period.The sum of concentration of seven OPPs in the water sample of Shangtang River in January ranged from 0.04 ug/L to 0.54 ug/L,which were lower than those of Shangtang River in September from0.17 ug/L to 1.71 ug/L.This result might be resulted from the decreasing usage of OPPs and the dilution of residual OPPs by the continuous precipitation in January.Based on the highest detectable concentration,the human health risk assessment of OPPs in the water samples of Shangtang River and Grand Canal was carried out.The results show that the total health risk of carcinogenesis in Shangtang River and Grand Canal were 1.0×10^-77 and 9.4×10^-8,respectively.All of them were equal to or lower than 10^-7,indicating no carcinogenic health risk.The total non-carcinogenic health risk of Shangtang River and Grand Canal water samples were 2.1×10^-33 and 9.4×10^-4,respectively,which were much smaller than 1,suggesting no non-carcinogenic health risk.（3）Based on the positive photoionization ion mobility spectrometry with acetone as dopant,a rapid method for OPPs analysis was established.The concentration of dopant was optimized for different OPPs.The optimal acetone concentration for detecting fenthion and chlorpyrifos was 0.07 mg/L,and that for detecting imidan was 0.26 mg/L,and that for detecting phosphamidon,dimethoate and isocarbophos was 2.33 mg/L.When the dopant concentration was increased from0.07 mg/L to 2.33 mg/L and further to 19.94 mg/L,the ion peaks of fenthion and dursban were inhibited successively,while the ion peak of dimethoate signal was insistent on the spectrum.The results show that switching the reagent molecules concentration can realize the selective detection of OPPs.At the optimal dopant concentration,the LOD of fenthion,dursban,imidan,phosphamidon,dimethoate and isocarbophos were 0.2,0.3,0.6,0.5,0.3 and 0.2 mg/L,respectively.