Development And Application For Test Method Of 82 Kinds Of Pesticides In Groundwater

Pesticides play an important role in the field of agricultural production in our country.The pollution of pesticide in groundwater is serious,and the trend of pesticide production and consumption has risen steadily in China.In recent years,the amount of pesticide production reached up to 3.7 million tons,and consumption of pesticide was estimated to be about 0.3 million tons.The original analytical methods can not satisfy the detection of new,toxic and harmful pesticides over time.Various standards in our country regulate allowable concentration of partial pesticides in groundwater.But with the development of chemical,biology and medicine technologies,the type of pesticide in standards need to be supplemented and completed.According to analyzing pesticide pollution in groundwater and various standards,we had selected some pesticides which are common,used extensively and had high toxicity to develop detection method by GC-MS.And the pretreatment method of sample by C18 solid phase extraction was also studied.The work in this study could offer a technical support for groundwater pollution investigation in our country.The main results were listed as following:1.Analysis methods of 82 kinds of pesticide in water had been established.The linear 82 pesticides were good(R2>0.99).Detection was finished in 37 minutes.Instrument detection limit was determined to be 1-50 ng/L.Relative standard deviation(RSD)of parallel samples was less than 5%.This method had some advantages such as fast,high sensitivity and good parallelism.2.The method of SPE for enriching groundwater samples was set up using C18 solid phase extraction with automatic solid-phase extraction apparatus.Extracting agent was the mixture of ethyl acetate and acetone(ethyl acetate: acetone = 3:1).The recoveries of 82 kinds of pesticides was between 50% and 130%.The experiment set up 8 groups of parallel samples and RSD of 82 pesticides was less than 30%.Compared with traditional liquid-liquid extraction pretreatment method,SPE was easy to operate,small affected by human operation and the organic solvent using in SPE has lower toxicity.The enrichment ratio of water was 1000 times,and method detection limit(MDL)of all pesticides was below 200 ng/L.3.20 groups of karst groundwater samples from kaiyang and zhenning in Guizhou province had been detected using the whole method The recovery of laboratory fortified sample matrix(LFM)ranged from 52% to148%,average of recovery of surrogate standard(SS)was 70.6%,relative standard deviation of SS was 5.8%.4.In the whole sample,more than 50 kinds of pesticides were detected.Detection rate of atrazine,fenthion,malation,methyl parathionetcare were 75%?45%?30% and 30%,respectively.This result indicated that atrazine may be the main herbicide,and fenthion,malation,methyl parathion may be the main instecticide in these places.Besides,some pesticides such as BHC,DDT which had been banned were still detected,and the detection rate of BHC was up to 65%.This observation suggested that these kinds of pesticide were used in the area.