Preliminary Studies On Risk Assessment And Residual Characteristic Of Organophosphorus Pesticides In Vegetable And Rice Processing Operation

In this paper, the effect of food processing on residual changes of seven representatives of the organic phosphorus pesticides such as dichlorvos, acephate, diazinon, malathion, chlorpyrifos, parathion and triazophos in tomato, peppers, cabbage and rice processing operations were studied. And the relationship between physical and chemical properties of the seven pesticides, such as water solubility, vapor pressure, Kow value and the effection of food processing on residue variation was also investigated.Hydrolysis test of organic phosphorus showed that, in addition to diazinon degradation more quickly in acidic media, the other six pesticides were easily degraded in alkaline media. Moreover, the degradation rates of these six pesticides in alkaline media were strongly influenced by temperature. For high-temperature (100℃) volatilization investigation, chlorpyrifos and diazinon showed a high volatility.For tomato, the peeling processing indicated that the removal rate of pesticide residue may vary by the value of Kow; the saucing processing showed that the residual concentration of acephate changed slowly, and the degradation speed of other pesticides both related to pH value and their heat-related instability. For chilli sauce, the residual concentration of organic phosphorus in brine increased while the content of salt decreased. However, the residue concentration of pesticide in chilli showed the negative relationship to its fat-soluble property, the higher fat-solubility, the higher concentration while the content of salt decreased. Result also showed that the residue concentration of deliquescent pesticide related to the water-loss rate in the process of chilli sauce, the distribution ratio of pesticide between pepper and brine conformed with their Kow values. Compared the fortified sample, the residue of pesticide in the field sample was easier to clean out.Additionally, based on the above study, a fixed or deterministic method was used to assess dietary intake risk of chlorpyrifos, result showed the%ADI and%ARfD values were both less than 100, which indicated that chlorpyrifos belonged to the relatively low risk pesticide.