Risk Assessment Of Mixed Pesticide Residues In Vegetables

Pesticide residues have become an important hazard to the quality and safety of vegetables,and the increased frequency of pesticide use during production and transportation has a direct impact on people’s dietary safety.With the progress of the times,the concept of diet has changed from "burp" to "eat well",and people are more concerned about the potential hazards of vegetables,especially the impact of pesticides in vegetables on people’s health.Pesticide residues are often present in a mixture of fruits and vegetables rather than in a single form.In this paper,a summation of risk quotients is used to calculate individual pesticide risk quotients using the amount of pesticide residues in vegetables,and the sum of the calculated pesticide risk quotients is used to assess the risk of a mixture of pesticide residues in vegetables.The total risk value can reflect the risk status of pesticide residues to humans in another way and provide a comprehensive reference for pesticide residue monitoring.The main findings of this paper are as follows:1.A new method for the determination of 17 pesticide residues in vegetables by liquid chromatography-mass spectrometry(LC-MS)was developed and applied to the actual samples.the correlation coefficients of the 17 pesticide residues were greater than 0.999,the three matrix effects ranged from 71.4 to 134.2% and the matrix effects were low,so substrate standard solutions were used for quantitative analysis;the average recoveries and relative standard deviations ranged from 83.2% to 110.5% and 0.3% to 7.5%.The method was evaluated to be of good accuracy and precision and met the detection requirements.2.The overall exceedance rate of 83 samples was 4.8%.2 samples exceeded the standard in W city,with a passing rate of 93.1%;2 samples exceeded the standard in Y city,with a passing rate of 80.0%,while the passing rate of the rest of the cities was 100%.In terms of the passing rate of various vegetables,the passing rate of pepper samples was 83.3%,with2 exceeded samples,both of which were pyraclostrobin;the passing rate of cowpea samples was 90.9%,with 2 exceeded samples,both of which were mefenoxam;and the passing rate of the rest of vegetables was 100%.From the detection of pesticide residues in various types of vegetables,there is a situation of using unregistered pesticides and lack of limit standards.Based on the actual production and regulatory needs,we propose a list of pesticide residues for which limit standards are urgently needed: Carbendazim(Cabbage,Celery);Dimethomorph(Cabbage);Propamocarb(Celery);Cyromazine(Chili,Cowpea).List of pesticides in urgent need of registration: Carbendazim(Cabbage,Celery);Dimethomorph(Cabbage,Celery);Cyromazine(Chili,Cowpea);Pyraclostrobin(Celery);Propamocarb(Celery);Chlorantraniliprole(Celery).3.A mixed risk assessment of pesticide residues in vegetables was carried out with reference to the results of pesticide residue monitoring.By querying the relevant parameters,the single risk values of various pesticides were calculated using a quadratic poisoning model,and finally summed to obtain the total risk values.Vegetables with high mixed risk were identified through risk ranking as Celery,Cowpea and Chili.The key risk factors affecting the quality and safety of Celery,Cowpea and Chili are Pyraclostrobin,Cyromazine and Pyraclostrobin respectively.The key risk factors were identified to be the failure of farmers to apply the recommended dose,frequency and interval of application.It is recommended that the relevant administrative authorities strengthen the relevant training and supervision.