Characteristics And Risk Assessment Of Herbicides Residue In Coastal Shellfish In Shandong Province

With the development of agricultural modernization,more and more pesticides are used in agricultural production,herbicides as an important part of pesticides has been widely used,the resulting environmental problems and food safety problems have caused more and more concern.In the process of spraying,the pesticide that is actually acting on the crop accounts for only 10% to 30% of the total amount of the application,and the rest enters the soil,the atmosphere and the lake,and thus affects the marine environment and seafood.Methods were established to determine 16 kinds of herbicides in seawater and aquatic products by gas chromatography-mass spectrometry(GC-MS).A preliminary risk assessment of herbicide residues in the main cultured shellfish in Shandong Province was conducted.The main contents and results of this paper are as follows:1.Methods were established to determine 16 kinds of herbicides in seawater and aquatic products by gas chromatography-mass spectrometry(GC-MS).1)A method was established to determine 16 kinds of herbicides in seawater by gas chromatography-mass spectrometry(GC-MS).The samples were concentrated,purified and eluted on a HLB solid phase extraction cartridges,and the elutions were evaporated to dry by nitrogen blow.Then the analytes were dissolved with ethyl acetate,determined by GC-MS in selected ion monitoring mode and quantified by the external standard methods.The experimental results exhibit good linearity between cynazine and pendimethalin in the range of 4.0~200 ?g/L,and their detection limits are 10.0 ng/L.The other 14 herbicides show good linearity in the range of 2.0~100 ?g/L,and their detection limits are all 5.0 ng/L.The average recoveries range from 78.3% to 115% with relative standard deviations of 4.4%-9.9%.The method is simple,accurate,and is especially suitable for testing 16 kinds of herbicides in seawater.2)A method for determination of 16 herbicides residues in aquatic products by gel permeation chromatography-solid phase extraction-gas chromatography-mass spectrometry was established.The sample was extracted with dichloromethane and ethyl acetate mixed solution,then cleaned up by gel permeation chromatography and purified by solid phase extraction column.Analyses were determined in selected ion monitoring and quantified by external method.Pendimethalin and cyanizine show good linearity in the range of 4~200 ?g/L and other herbicides show good linearity in the range of 2~100 ?g/L.Correlation coefficient is no less than 0.9970.Quantitation limit of propazine,atrazine,terbutylazine,simazine,desmetryn,prometryn,ametryn,metolachlor were 1.0 ?g/kg.Quantitation limit of acetochlor,alachlor,butachlor,pretilachlor,cyprazine,simetryn were 1.5 ?g/kg and quantitation limit of pendimethalin,cyanizine were 2.0 ?g/kg.Average recoveries range from 70.2%~ 103% and relative standard deviation of the method was 5.1%~9.5%.The method with good reproducibility,high recovery rate,the precision and accuracy to meet the terms of residue testing requirements,and could be used for the determination of 16 herbicide residues in aquatic products.2.The residues and distribution characteristics of 16 herbicides in seawater,sediments and shellfish in R and D waters were investigated.R sea area detected 6 species,including Atrazine,Prometryn,Simetryn,Ametryn,Pendimethalin,Acetochlor.In addition,the pollution of herbicides with the seasonal changes in the larger,the first quarter of R sea pollution is most serious,coastal pollution is serious,indicating that the herbicide pollution for the land.Under the same conditions,the enrichment coefficient of oyster on the Ametryn and Simetryn was greater than that of atrazine.D part of the sea area of herbicide pollution compared to R serious.In the river estuary and seawater,16 kinds of herbicides were detected.From the space point of view,the detection of the concentration of sea area is generally less than the river and estuary waters,Xiaoqing River in the herbicide detection of the types and concentrations are higher than other stations.From the time point of view,May,July all kinds of herbicides concentration reached the peak of the year.There were four kinds of sediments,among which the detection rate of acetochlor was the highest,and the herbicide detected in the sediment had no obvious correlation with the residual condition in seawater.3.Risk Assessment of Herbicide Residue in Main Cultured Shellfish in Shandong ProvinceIn order to investigate the residual status of herbicides in Shandong coastal shellfish,samples were collected from 13 sampling points in shellfish culture areas and analyzed by gas chromatography-mass spectrometry(GC-MS)for the determination of 17 herbicides in shellfish.The potential risks were evaluated by EPA recommended health risk assessment model and Index of Food Safety method.The results showed that five herbicides were detected in 33 shellfish samples,including ametryn,acetochlor,metolachlor,prometryn and atrazine.The detection rate was 69.7%.Periglypta petechialis,Ruditapes philippinarum and Crassostrea gigas have a higher detection rate.From the spatial distribution,herbicide pollution in shellfish was more serious in agricultural industrial areas.Most of the herbicides detected in May and June.Moreover,by calculating their risk factors,the health risks of herbicide residues in shellfish is small.