Study On Environmental Risk Assessment And Control Strategy Of Pesticides Commonly Used On Vegetables

China is a large country of vegetable production and consumption.There are many kinds of pests and diseases in the process of planting vegetables.Pesticides have become the rigid demand in vegetable production.According to statistics,there are nearly 9000 kinds of pesticides registered on vegetables now.The heavy use of pesticides can cause residues and pollution.Risk assessment is the basic approach of pesticide management.Its purpose is to evaluate the possibility and severity of the adverse effects of pesticides on human health and the environment.Most pesticides risk assessment has been carried out by developed countries or international organizations,and also applied to pesticide management.However,it started relatively late in China,and the technology has not been applied systematically and scientifically.This paper is to systematically identify hazards and carry out exposure assessment of pesticides commonly used in vegetables,characterize the risk of surface water,groundwater and non-target organisms,what's more,set up the control strategy of priority control pesticides used on vegetable and provide the scientific basis for risk management of pesticides used on vegetable in China.The main results and conclusions are as follows:1.Pesticides are mainly registered on cruciferous vegetables,cucumbers and tomatos in China.In recent 8 years,the registered amount of pesticides used on vegetables showed a downward trend in China.26 pesticides that vegetables commonly used such as lambda-cyhalothrin were screened to further study.2.The database published by some developed countries or international organizations can provide data support for pesticides risk assessment in China.Health and environmental hazards databases about pesticides of the developed countries and international organizations were investigated.On the basis of comprehensive analysis of the authority,integrity and reliability of the data provided by each database,29 databases for health hazard preliminary screening and18 databases for environment hazard preliminary screening of pesticides were selected for hazard assessment in China.3.Some pesticides used on vegetable may pose unacceptable risks to surface water.GENEEC2 model was used to predict the exposure concentrations of commonly used vegetable pesticides in surface water.The methods of database retrieval and evaluation factor were both used to estimate predicted no effect concentration of surface water,entropy method was used to characterize environment risk of surface water.Entropy evaluation method was applied to characterize the risk of commonly used vegetable pesticides to surface water.The results showed that 21 pesticides including dipterex,dichlorvos,chlorpyrifos,acetochlor,lambda-cyhalothrin,thiram,carbendazim,mancozeb,chlorothalonil,pendimethalin,chlorfenapyr,iprodione,tebufenozide,imidacloprid,pyrimethanil,azoxystrobin,chlorantraniliprole,dimethomorph,cyromazine,emamectin benzoate and pymetrozine,ranking by the risk from high to low,would produce unacceptable risks to aquatic organisms by using their formal registration doses,while another 4 pesticides including phosethyl-Al,clethldim,polyacetaldehyde and flonicamid would produce acceptable risks to aquatic organisms.Senior risk assessment results showed that 7 pesticides including acetochlor,chlorpyrifos,chlorothalonil,pendimethalin,mancozeb,dipterex and dichlorvos,ranking by the risk from high to low,would produce unacceptable risks to aquatic organisms by using their formal registration doses on vegetables.10 water samples were collected from a watershed in Binzhou City.The concentration of 9 pesticides in the water samples was determined by LC-MS/MS.The results showed that 5 target pesticides were detected and the surface water risk assessment suggest that Acetochlor may pose a potential risk.4.The models of EPI Suite?and PBT profiler were utilized to predict the values of Kow and BCF.The method of literature investigation was used to acquire the values of BCF and CT_95.?Pesticide registration The guidelines for environmental risk assessment?was referenced to complete environmental risk assessment of bioconcentration on aquatic organisms.The results showed that the 3 effective components of lambda-cyhalothrin,chlorpyrifos and pendimethalin would produce unacceptable risks due to bioconcentration,and the risks of the other 22 effective components would be acceptable.5.The risk of pesticides used on vegetable to groundwater is acceptable in China.In order to confirm the environment risk in groundwater for pesticides that vegetables commonly used,the models of China-Pearl and SCI-GROW were utilized to assess the environmental exposure,the predicted no effect concentration?PNEC?for 25 pesticides were derived from exposure factors of Chinese adults and children,and the method from?Pesticide registration The guidelines for environmental risk assessment?was referenced.It was found that the values of PEC_gw for25 pesticides were in the range of 0-18.340?g/L,and the values of PNEC_gw for adults were from 0.003 to 19.654 mg/L,while for children were between 0.001 mg/L and 23.253 mg/L.RQ_gw for both adults and children were less than 1,which indicated that when the dosage of pesticides were used in accordance with the registration,the environment risk of drinking ground water where pesticides were applied was acceptable for Chinese adults and children at all age groups.An effective and sensitive analytical method has been developed to detect tefuryltrione in water by ultra high performance liquid chromatography coupled with tandem mass spectrometry.6.Some pesticides used on vegetable may pose unacceptable risks to birds and bees.Birds risk assessment of 25 pesticides commonly used on vegetables was carried out by using the methods of database retrieval,literature investigation and hypothesis evaluation.Results showed that,birds acute risks of six pesticides including dichlorvos,chlorfenapyr,trichlorphon,chlorpyrifos,metaldehyde and thiram would be unacceptable in accordance with the dosage and registration method.Birds short-term feeding risk of chlorfenapyr would be unacceptable.The above pesticides should be avoided in bird area.Bees risk assessment of 25 pesticides commonly used on vegetables was carried out by using the methods of database retrieval,literature investigation and hypothesis evaluation.Results showed that,all the pesticides used in vegetables would produce unacceptable risks.Attention should be paid to the protection of honeybees while applying pesticides in vegetable fields.Applying pesticides to honey crops at flowering phase should be avoided.7.The methods of Ronnie,evaluation factor and risk matrix were all used to establish the priority control pesticide list.After screening,a total of 7 pesticides including chlorpyrifos,lambda-cyhalothrin,emamectin benzoate,chlorfenapyr,dichlorvos,trichlorfon and pendimethalin were identified as the priority control pesticides.The control strategies of prohibition,avoidance and substitution were put forward to priority control pesticides commonly used on vegetables.