Safety Evaluation For Pesticide Residue In Vegetables Based On Monitoring Big Data

To control the level of pesticide residues in agricultural products,China's agricultural departments have organized large-scale monitoring of pesticide residue risks and acquired massive effective monitoring data,laying a good foundation for pesticide residue risk assessment and management.However,the problems such as low associated data application level,lack of Quantitative safety assessment methods,etc.,hinder the further improvement of the level of decision-making and management for pesticide residue risks.In this thesis,based on the needs of pesticide residue assessment and management in China,taking pesticide residues in vegetables as an example,we have carried out the safety assessment based on the maximum residue limit and the improved Nemerow index by using the associated big data,systematically analyzed the distribution and major risk sources of pesticide residues in vegetables in China,and proposed a five-level assessment system for pesticide residue risks.In addition,we have assessed the cumulative exposure risk of organophosphorus pesticide residues in vegetables using the integrated probability assessment method with methamidophos as a reference pesticide and carried out quantitative analysis of dietary exposure risk levels and characteristics of 10 consumer groups in China.The analysis results show that:(1)The overall qualification rate of pesticide residue detection in vegetables in China is 96.77%,and the overall residue level is low and it is getting lower gradually year by year.(2)The distribution level of pesticide residues in vegetables in China is uneven,and the main potential risks are concentrated in a few “product + pesticide” portfolios,such as carbofuran in beans and solanaceous vegetables,and dimethoate and fipronil in leafy vegetables.Controlling the level of pesticide residues in those vegetables and portfolios with a relatively high nonconformity rate is of great significance for reducing the overall level of pesticide residues in vegetables.(3)In terms of monitored links,the conformity rate of back-end wholesale markets and supermarkets is lower than that of the front-end bases and farm produce markets.The changing trend of the conformity rate of the monitored links is contrary to the expectation of pesticide degradation.On the one hand,this reflects that there are still some problems with the sampling work in risk monitoring such as low sampling coverage and poor sample representativeness,and on the other hand,it also reflects a low level of standardized and large-scale vegetable growing in China.A large number of products grown by the decentralized production mode have entered the back-end links,so it is necessary to further strengthen risk control through market admittance management.(4)The safety assessment result of the pesticide residue risk index constructed based on the improved Nemerow index is consistent with the assessment result based on the maximum residue limit,but it is more sensitive in the ability to identify the source and level of risk,and the assessment result is a dimensionless quantitative value,which is more conducive to risk communication.(5)The cumulative exposure of the 10 consumer groups including children in China to 19 organophosphorus pesticides in edible vegetables at P99.9 and P97.5 did not exceed the acute reference dose(ARfD)or the acceptable daily intake(ADI),and the exposure of residents in China is relatively low based on the existing research results in major developed countries..The pesticide residue index,the 5-level assessment system and the multi-residue cumulative risk probability assessment method proposed in this paper meet the demands for quantitative safety assessment for pesticide residues and make up for some shortcomings of the original qualitative assessment method.These methods do not limit the applicability of products and can be quickly promoted to the safety assessment of pesticide residues in other types of agricultural products,providing the technical support for relevant risk management and decision-making.