毒死蜱在杨梅果实中的残留及消解动态

为探明毒死蜱在杨梅果实中的残留消解动态和最终残留量，于2013-2015年在浙江省临海市进行了毒死蜱在杨梅果实中的残留消解动态和最终残留量试验。结果表明:于杨梅春梢（幼果）生长期，在树冠均匀喷施48%毒死蜱乳油800倍液1次的施药条件下，毒死蜱在‘东魁’和‘临海早大梅’2个品种果实中的消解动态基本一致，均符合一级动力学方程，半衰期为4.60~5.78 d，降解速度较快。综合3年试验结果，施药后23 d，毒死蜱在杨梅果实中的残留量为0.26~0.45 mg/kg，低于中国（苹果、梨、荔枝和龙眼）及日本（其他浆果）最大残留限量标准（MRL，1 mg/kg）；施药后34 d，毒死蜱在杨梅果实中的残留量为0.074~0.28 mg/kg，低于香港草莓中MRL值（0.3 mg/kg）；但施药后44 d，毒死蜱在果实中的残留量为0.073~0.13 mg/kg，仍高于欧盟蓝莓及桑椹中毒死蜱的MRL值（0.05 mg/kg）。膳食风险评估结果表明，施药后23、27、34和44 d采收的杨梅果实中毒死蜱对2~6岁、7~14岁、18~30岁和60~70岁4类人群的膳食摄入风险商值及急性膳食风险均较低，处于安全水平。

Residues and dissipation dynamics of chlorpyrifos in Myrica rubra fruits

In order to assess the dissipation and residues of chlorpyrifos inMyrica rubra fruits, the dissipation dynamics and final residue trials of chlorpyrifos inMyrica rubra fruits were carried out from 2013 to 2015. Results showed that: when the whole tree was sprayed once with 800 times diluted solution of 48% chlorpyrifos EC in the spring shoots (young fruit) growing season ofMyrica rubra, the dissipation of chlorpyrifos in ‘Dongkui’and ‘Linhaizaodamei’cultivars were of the similar type, fitting to the first order kinetics with half-lives varied from 4.60 to 5.78 days. The half-life was short and its dissipation speed was fast under those conditions. The 3-year research results demonstrated that the residues of chlorpyrifos inMyrica rubra fruits varied from 0.26 to 0.45 mg/kg 23 days after spraying,which was lower than the maximum residue limit (MRL, 1 mg/kg ) of China (apple, pear, litchi and longan) and Japan (other berries). Thirty-four days after applying, chlorpyrifos inMyrica rubra fruits varied from 0.074 to 0.28 mg/kg, which is below the MRLs of strawberry in Hong Kong (0.3 mg/kg). However, 44 days after spraying, chlorpyrifos inMyrica rubra fruits (0.073-0.13mg/kg) were still higher than the MRLs of blueberries and mulberries in EU (0.05 mg/kg). The dietary intake risk assessment showed that after 23, 27, 34 and 44 d pesticide interval, the RQ and ARfD of chlorpyrifos in Myrica rubra fruits were very low (significantly lower than 1), and within safe level for people aging between 2-6, 7-14, 18-30 and 60-70.