Detection And Human Dietary Risk Assessment Of Pesticide Residues In Self-produced Vegetables In Wulanchabu

In this thesis,gas chromatography and liquid chromatography-mass spectrometry were used to detect 31 pesticides in self-produced vegetables in 7 areas of Wulanchabu from 2019 to 2020,the detection rate and pass rate were evaluated and analyzed.At the same time,the daily intake of pesticides(EDI),the target hazard factor(THQ)and the risk index(HI)were used to assess the risk of human dietary exposure.The results of pesticide residues showed that:(1)A total of 666 batches of vegetable samples were tested in two years,and the average pass rate reached 97.1%,which was at a high level.(2)In 2019,1 banned pesticide was detected as Parathion;5 restricted pesticides were detected,namely Phorate,Carbofuran,Chlorpyrifos,Triazophos,and Dimethoate.Among them,the detection rate of Chlorpyrifos was the highest,and the excess rate of Triazophos was the highest;14 kinds of conventional pesticides were detected,among them,the detection rate of Imidacloprid was the highest,and the excess rate of Acetamiprid was the highest.Banned pesticides in 2020 were not detected;3restricted pesticides were detected,namely Carbofuran,Chlorpyrifos and Methomyl,of which Chlorpyrifos had the highest detection rate and Carbofuran had the highest exceeded rate;12 kinds of conventional pesticides were detected,of which Imidacloprid had the highest detection rate and Abamectin had the highest excessed rate.A total of 155 batches of fungicides and 191 batches of pesticides were detected in the past two years.In 2019,the proportion of mixed use of pesticides in vegetables was 40.8%;in 2020,it was 31.2%,showing a downward trend.(3)The two-year average pesticide detection rate of different vegetable species from high to low were: solanaceous > leafy vegetables > melon >rhizome;the pass rate from high to low were: solanaceous > rhizome > melon > leafy vegetables.(4)The two-year average pesticide detection rate of different vegetable growers from high to low were: individual>professional cooperatives>enterprises;the pass rate from high to low were: professional cooperatives>enterprises>individuals,indicating that the problem of pesticide residues in vegetables for individual growers was relatively prominent.(5)Among different vegetable producing areas,the detection rate of vegetable pesticides in Fengzhen was low and the pass rate was high;the detection rate of vegetables in Chayouqianqi was high and the pass rate was low;the other five areas were basically the same,with an average detection rate of less than 40% in two years,the pass rate is about97.6%.The results of human dietary risk assessment showed that:(1)The THQ of the pesticides detected in the two years were below the limit value,and the single ingestion of pesticides had no significant risk to human health.(2)HI in 2019 is higher than the limit value,the compound risk is unacceptable,and the restricted pesticides that had the greatest impact on HI;In 2020,the average HI is lower than the limit value,the compound risk was within the acceptable range,and the conventional pesticides had the greatest impact on HI.(3)HI of leafy vegetables have exceeded the limit value for two consecutive years,which needs special attention.