Residues and its dietary exposure estimation of indoxacarb and chlorpyrifos in pakchoi cabbage

In order to provide the technical support to the safe production and dietary risk assessment for pakchoi cabbage,the residue trial and dietary exposure estimation of indoxacarb and chlorpyrifos in pakchoi cabbage were carried out.The results showed that the normal dosage of indoxacarb(40.5 g·hm-2) and chlorpyrifos(540 g·hm-2) were used under the protected field conditions,the primary residues were 3.88 and 20.6 mg·kg-1,and the half-life(T1/2)were 1.4 and 1.1 d,respectively;After 7 days of spraying,the residue of indoxacarb and chlorpyrifos could meet the limits of CAC,the U.S.A.and Japan.The dietary exposure estimation showed that different age groups had different risk quotient,the risk quotient of 2-10 age group was about 50% higher than the adults'.The theoretically chronic risk quotient of indoxacarb was lower than 100 at the 5 d interval with the normal dosage and 7 d interval with double dosage,the theoretically acute risk quotient value was always lower than 100,which was all acceptable.The theoretically chronic risk quotient value of chlorpyrifos with different intervals was approaching or above 100,the theoretically acute risk quotient decreased to be lower than 100 after 3-day interval.Therefore,the residue trial and dietary exposure estimation of indoxacarb and chlorpyrifos showed that the dietary exposure risk of indoxacarb was low and safe.But the use of chlorpyrifos could cause high risk,and should not be used in the pakchoi cabbage production.