马拉硫磷在西葫芦中的残留行为及膳食摄入风险评估

Residues behavior and dietary intake risk assessment of malathion in Cucurbita pepo L.

利用气相色谱-火焰光度检测器（GC-FPD）测定了马拉硫磷在西葫芦中的残留量,根据2016年湖南、山东、北京、安徽、山西和黑龙江6地马拉硫磷在西葫芦中的规范性残留试验,对中国各类人群和不同作物中的马拉硫磷进行了膳食风险评估。样品用乙腈提取,丙酮置换乙腈后,GC-FPD检测。结果表明：在0.02~8.0 mg/kg添加水平下,马拉硫磷在西葫芦中的回收率在88%~109%之间,相对标准偏差（RSD）为5%,定量限（LOQ）为0.02 mg/kg。湖南和山东的消解动态试验结果显示,马拉硫磷的半衰期为2.74~4.65 d,属于易降解农药;6地的最终残留试验结果表明,距最后一次施药3、5、7 d后,西葫芦中马拉硫磷的最终残留量在〈0.02~0.049 mg/kg之间。针对西葫芦的膳食风险评估结果显示,中国各类人群对马拉硫磷的国家估计每日摄入量（NEDI）为0.115~0.207μg/（kg bw·d）,风险商值（RQ）为0.000 4~0.000 7;全膳食暴露风险评估结果显示,马拉硫磷在各类食物中的NEDI值为82.251μg/（kg bw·d）,RQ值为0.275 1,表明马拉硫磷在西葫芦中的长期膳食摄入风险较低。推荐中国马拉硫磷在西葫芦上的最大残留限量值（MRL）为0.1 mg/kg,可确保中国西葫芦的食用安全性。

The residues of malathion in Cucurbita pepo. was determined using gas chromatography equipped with flame photometric detector（GC-FPD）. The standard residue trials of malathion in C.pepo were carried out in Hunan, Shandong, Beijing, Anhui, Shanxi and Heilongjiang in 2016. The dietary intake risk assessment to different populations and different foods based on the residual data of malathion was conducted. The C. pepo samples were extracted with acetonitrile, determined by GCFPD after the displacement of acetonitrile with acetone. With the fortified level from 0.02 to 8.0 mg/kg in C. pepo samples, the recoveries ranged from 88% to 109% with the relative standard deviations（RSD） of 5%. The limit of quantitation（LOQ） of the method was 0.02 mg/kg. The dissipation dynamic test results obtained from Hunan and Shandong showed that malathion was easily degradable, and the half-life of malathion was 2.74-4.65 days. The final residues in C. pepo from six provinces were 0.02-0.049 mg/kg with interval 3, 5 and 7 days after last applied. The dietary risk assessment results showed that the national estimated daily intake（NEDI） was between 0.115-0.207 μg/（kg bw·d） and the risk quotients（RQ） were between 0.000 4-0.000 7 for different populations in China. The total dietary exposure risk assessment results indicated that the NEDI of malathion in all kinds of foods was 82.251μg/（kg bw·d）, and the RQ was 0.275 1, which demonstrated that malathion applied to C. pepo had low risk. The maximum residue limit（MRL） of malathion in C. pepo is recommended to be 0.1 mg/kg in China, which would ensured dietary intake safety of C. pepo.