摘要
【目的】从农田到餐桌全程研究毒死蜱、氟虫腈在稻米生产及食用加工过程中的残留消解规律,阐明不同用药量、用药次数与稻米中农药残留的关系,并以理论(MRL)与实际残留数据,结合食用前加工过程的去除消解动态研究,分别计算入口前的残留值,进行理论和准确暴露评估,分析大米的食用安全性,并以健康风险评估结果为理论依据,从食用安全的角度对实际生产的用药模式进行调整,并重新界定最适的安全间隔期。【方法】田间试验参照农药残留登记准则(NY/T788-2004)进行,采用气相色谱法分析农药残留在稻米曝晒、贮存、淘洗、蒸煮过程中的消解规律,采用饮食曝露模型——参考剂量百分比(POR)、暴露边缘(MOE)对不同年龄、性别人群进行急、慢性健康风险评估。【结果】(1)稻米中的农药残留及食用风险与田间用药剂量及次数正相关,随着施药剂量、次数的增多,残留量增大,对人健康风险上升。(2)食用加工过程中残留消解研究表明,经曝晒、贮藏、淘洗、蒸煮后两种药剂的降解率分别为91.6%和96.16%,其中蒸煮过程对药剂的降解作用最明显。(3)对以稻米为主食的不同年龄、性别人群的暴露评估表明,稻米中毒死蜱对人健康风险远高于氟虫腈;慢性健康风险分析表明,对所有调查人群毒死蜱为高风险率,氟虫腈为低风险率;急性健康风险分析表明,毒死蜱对儿童具有高风险,尤其是对农村人群中的男性风险较高,氟虫腈对所调查人群均为低风险率;不同年龄与性别组成的人群面临的风险不同,14岁前男孩面临的风险大于女孩,农村地区儿童所面临的健康风险高于城市儿童;14岁至成年之后的女性面临的风险高于男性,农村人群面临的健康风险高于城市人群。(4)研究发现安全收获间隔期的合理界定是降低健康风险的关键点,当安全间隔期延长至14d时,田间试验中所有处理剂量稻米的食用健康风险均降至可接受范围。【结论】稻米的食用安全性不乐观,大米中残留的毒死蜱对人群的健康风险较大,田间应减量使用,建议单次使用剂量不超过推荐剂量两倍,安全间隔期不少于14d,连续施用的间隔期不少于7d;基于氟虫腈的环境生态毒性,建议其在稻米中残留限量引用codex标准0.01mg·kg-1。
【Objective】 Degradation of pesticide residue (chlorpyrifos and fipronil) in rice from farm to dining table and risk assessment for human health were studied to reveal the magnitude of the risks faced by different populations having interest in rice,and to provide a guiding line for application of pesticide in field,and to refine and update the human health risk assessment data while helping to determine a MRL value and harvest interval. 【Method】 A field trial was designed following the protocol of NY/T788-2004,and residues in harvested rice were monitored by GC. Residue levels of post-harvest-applied chlorpyrifos and fipronil during storage,exposure to sunlight,washing and cooking processes (boiled rice) of brown rice were investigated; Several perimeters of evaluation model of dietary exposure evaluation model (DEEM) was employed to estimate the acute and chronic risk faced by different populations of interest,POR (percent of RfD ) and MOE (Margin of the exposure) were included. 【Result】 A positive correlation was found in pesticide residue betweon harvested rice and treatment of pesticide in field,residue presented in harvested rice raised with the raising application rate and treatment times. The concentration of pesticide residue decreased as a function of time during rice storage and preparing and cooking processes. The pesticide residues decreased by 91.16% and 96.16% at the end of the experimental period. The boiling process had a significant effect on the major degradation of pesticides. Risk assessment to human health showed that chlorpyrifos residue in rice should be concerned,and dietary exposures from eating food crops treated with chlorpyrifos exceeded the level of concern for the entire population. Chronic dietary risk from food alone showed that dietary exposures from eating food rice treated with fipronil was below the level of concern for the entire population,including children. Acute dietary (food only) risk estimate for chlorpyrifos as percent of aPAD (acute population adjusted dose) over 100% frequently when the treatment rate and times raised,the result showed that risk faced by boys under the age of 14 was higher than the girls at the same age,and the risk level reversed for the subpopulation at the age above 14. The risk faced by population of rural residential region was more serious than the risk faced by population of urbanite with rice as thceir food,the most sensitive population subgroup,children and male in population of countryside faced higher acute dietary risk than the other subpopulation groups. Thus acute dietary risks from food (rice) alone are of concern. Re-identification of harvest interval found to be the critical point and most important measure to mitigate risk to all population for rice safe eating. The results showed that all risk level of trials for human health decreased to acceptable range when the harvest interval extended to 14 days. 【Conclusion】 Risk quotients indicate that multiple application and double rate of chlorpyrifos increase the risks to entire population and prolong exposures to toxic concentrations. To address these risks,a number of measures including reduced application rates (should not be doubled at single application),increased retreatment intervals (longer than 7 days),extended interval of harvest (at least 14 days) will be needed. Concerning about the toxicity of fipronil to fish,bees and aquatic invertebrate specie,MRL of fipronil in rice is suggested being 0.01 mg·kg^-1,which followed the Codex regulation.
出处
《中国农业科学》
CAS
CSCD
北大核心
2010年第1期151-163,共13页
Scientia Agricultura Sinica
基金
江苏省自然科学基金资助项目(BK2006167)
国家科技支撑计划项目(2006BAK02A04)
关键词
稻米
风险评估
农药残留
毒死蜱
氟虫腈
rice
risk assessment
pesticide residue
chlorpyrifos
fipronil