Chlorpyrifos High Residual Reason In The Chinese Chives And Removing Technology Research

According to Chinese chives of pesticide residues often exceeds the status quo,Through the special studies on the deposition, absorption and conduction, residue, metabolism of chlorpyrifos in leek, the reason why chlorpyrifos residue exceed in leek was detected; a group method of removing pesticide residues in leek was founded through the leek cleaning processing, and the cleaning process is optimized to get the best method to remove pesticide residues as well as make the minimization of leek characteristic aroma and vitamin C loss.The main research contents and results were below as followed:1. Research on deposition of Chlorpyrifos in leek:By dipping chlorpyrifos on leek, weighing the change of the weight of the leeks before and after,at the same time with Chinese cabbage as the control plants, pesticide Dimethoate as control pesticide different chives and Chinese cabbage of Chlorpyrifos in loading, leek of chlorpyrifos and dimethoate loading.The results showed that: chlorpyrifos in leek was4.98%±1.24%,9.22%±1.08%in Chinese cabbage, the control of dimethoate was4.79%±0.98%, chlorpyrifos in leek in a dose was less than that in Chinese cabbage, Difference of dimethoate and chlorpyrifos in leek in the loading is not significant.2. Study on absorption and conduction of chlorpyrifos in leek:the leek root was irrigated by chlorpyrifos at the recommended dose with Chinese cabbage as control, leek root tissues of chlorpyrifos content was measured at different time, the results showed that, although at the7d, the residue concentration in leek edible part is less than that in Chinese cabbage, the residue was0.168mg/kg, higher than the national MRL of0.1mg/kg.By painting Chlorpyrifos in leek upper half parts, with Chinese cabbage as control, the results showed that, although chlorpyrifos residues in both the upper part and lower part was not higher than that of Chinese Cabbage, but at the7d leek, the residue was0.131mg/kg,higher than the national MRL of0.1mg/kg.3. The metabolic behavior of chlorpyrifos in leek. By spraying leek, with cabbage as a contrast crop, and dimethoate as a control pesticide, to study the activity variation of GST, ACP, AKP, GSH-PX, soluble protein in leek after spraying chlorpyrifos, the results showed that: the soluble protein of leek returned to normal in14ds under chlorpyrifos stress, the soluble protein of cabbage returned to normal in5ds, the soluble protein of leek returned to normal in3ds under dimethoate stress, the effect time of chlorpyrifos in leek was longer than that in cabbage, and longer than dimethoate in leek; the detoxifying enzymes GST, antioxidant enzyme GPX activity of leek was lower than that of cabbage under chlorpyrifos stress, this is the main reason why chlorpyrifos residue remains in high leek.4.The effects of cleaning methods with different cleaning mediums on chlorpyrifos in leek were studied. The study on cleaning chlorpyrifo in leek with different cleaning conditions of various temperature,times, citric acid solution of different concentrations, vinegar solution, sodium carbonate solution, sodium bicarbonate solution, salt solution, cleanser essence solution and different ultrasonic conditions was carried out, the results demonstrated that the best methods was water cleaning with removal rate of58.5%, then40.57%by3%o Liby,39.96%by3%o DIAO BRAND cleanser essence,36.79%by1%ovinegar solution,35.35%by3%o sodium bicarbonate solution,31.24%by1%o salt solution,26.46%by1%o sodium carbonate and citric acid solution,25.81%by ultrasoniccleaing.5. The optimization of multipl cleaning methods, three Factors of A inegar solution(%o), B sodium carbonate solution(%o), C salt solution(%o) were studied. Removal rate of chlorpyrifos was taken as the main evaluation index, features aroma of leek and Vc as the auxiliary evaluation index. The result Indicated that effects of Single Factor were A> C>B. The optimal combination is1%oinegar solution,3%o sodium carbonate solution,1%osalt solution, which could wipe off more than80%chlorpyrifos in leek, make chlorpyrifos reisude under0.01mg/kg, with the least loss of Vc and aroma. The step of the cleaning methods was to clean leek at40℃water for10mins twice first, then soke the leek in1%oinegar solution3%o sodium carbonate solution(%o),1%osalt solution for lOmins respectively.