【作者】 袁玉伟；

【导师】 叶志华；

【作者基本信息】 中国农业科学院 ， 农产品质量与食物安全， 2008， 博士

【摘要】 农药残留超标是农产品质量安全控制的热点和难点问题,农药残留的膳食暴露评估和限量指标制定是进行农产品质量监管的重要依据,在农产品的不同生产阶段需要相应的农药残留限量标准进行监管。本文以跟踪菠菜中农药残留限量的国际标准为线索,分析菠菜及其加工产品中农药残留标准现状;研究毒死蜱等农药在土壤、种植和加工过程中的数量动态变化,进行我国菠菜中农药残留的理论最大摄入量估计;根据试验农药的残留数据和加工因子提出几种常用农药在菠菜及其加工制品中的最大残留限量,并对我国菠菜中农药残留限量制定和控制提出建议。通过上述研究,主要结论性内容如下:一、分析菠菜中农药残留限量现状。不同国家对菠菜中农药MRL数量和分布差异大,日本对菠菜设定321个农药残留限量,其中大于0.1mg·kg^-1的数量163个,占总数量的50%左右,虽然肯定列表制度对我国菠菜出口影响大,但从农药的使用种类来看仍有很大的应对空间;而欧盟在菠菜及其类似物设定的残留限量约303项,明确菠菜中的有163项,而小于0.05mg·kg^-1的就有259项,约占总量的85%,是最为严格的标准。国际食品法典委员会（CAC）的菠菜标准中共计78项次,而限量小于0.1mg·kg^-1仅有10项,只占总量的12.8%。美国菠菜标准中有53项残留限量指标,小于0.1mg·kg^-1的限量指标只有3项,约占总量的5%,属于最为宽松的标准。总体来看,限量指标的严格程度依次是欧盟、日本、CAC和美国。菠菜的国际标准中农药残留限量种类涵盖杀虫剂、杀菌剂和除草剂,而我国的菠菜标准中尚无除草剂限量标准,且数量少于欧盟、日本和美国。我国菠菜及制品中限量标准之间衔接性差、种类和数量不统一,建议统一不同产品标准中的农药残留限量指标和判定规则。二、研究毒死蜱等农药在菠菜种植及加工中的残留动态。通过盆栽试验研究菠菜对土壤中毒死蜱残留的吸收情况表明,在一定范围内,菠菜对土壤中毒死蜱残留具有生长吸收作用,并且与土壤中的残留浓度呈正相关;出口企业在菠菜种植过程中,应该对土壤进行农药残留检测,避免由于菠菜吸收土壤中毒死蜱残留而影响出口。试验农药的田间降解动态结果表明,马拉硫磷降解速率最快,且初始残留量为4.5mg·kg^-1低于叶菜类的国家标准8mg·kg^-1,因此,叶菜类的国家标准不能直接用于菠菜标准;在叶菜类中毒死蜱现行0.1mg·kg^-1的标准过于严格,不适于在菠菜生产中使用;缺少霜霉威和甲霜灵等复配制剂农药在菠菜中的残留限量,残留限量和安全间隔期的设定要考虑农药在作物中残留降解速率和农药种类。水洗、漂烫和烘干加工能够降低菠菜中毒死蜱、氰戊菊酯和氯氰菊酯残留,减少膳食暴露量;冷冻干燥和热风干燥对菠菜中农药残留的损失分别农药的溶解度和蒸汽压有关,其中马拉硫磷在热风干燥中损失率达60%以上,而乐果在冷冻干燥中几乎没有损失;因此,加工企业要根据加工方式考虑菠菜生产中的农药使用种类。三、评估我国菠菜中农药的理论每日最大摄入量（TMDI）和制定限量标准。农药的膳食暴露评估是风险管理和限量指标制定的基础,采用TMDI的评估方式,计算我国菠菜标准中14中农药的膳食风险指数（%ADI）,结果表明拟除虫菊酯类农药的风险指数较低（12.2%⁴8.7%）,而有机磷农药的风险指数高;其中乐果、二嗪磷的风险指数分别为243.6%和121.8%,应该采取进一步的修正措施降低风险指数。采用不同的限量制定方法得出不同的农药残留限量和安全间隔期;其中以欧盟的设定方式符合实际生产和最为严格,毒死蜱、高效氯氰菊酯、马拉硫磷、甲霜灵和霜霉威农药在菠菜中MRL在原料菠菜中MRL分别为1、0.5、0.1、0.1和0.5mg·kg^-1,安全间隔期分别为7、7、3、14和14d。首次将农药在菠菜中的加工因子用于脱水菠菜中农药MRL的设定,根据毒死蜱、氯氰菊酯、氰戊菊酯和马拉硫磷在菠菜制品中的加工因子,结合原料中MRL,设定脱水菠菜中的MRL分别为5、6、3和3mg·kg^-1。四、我国菠菜及其制品中农药残留限量制定与控制的建议。菠菜中农药残留的控制和指标制定应该在连贯、持续和有效监控条件下的全程控制;不同阶段的指标项和指标值应该统一设定规则;限量的制定和执行要以风险评估作为基础,并结合实际生产和农药登记要求;菠菜中农药残留控制需要多方参,健全并理顺相关法律法规。本研究对我国菠菜出口中农药残留控制、限量指标制定和消费者的膳食暴露评估具有积极的理论价值和现实意义;对相关加工农产品中农药限量指标的设定也具有借鉴意义。更多还原

【Abstract】 Violation of standard limits of pesticide residue is one of the most important issues for the quality and safety control of agro-product; generally, monitoring and regulation of the quality and safety of agro-products are basically dependent on the dietary exposure assessment and residue limit establishment. There should be different limit standards for pesticides in spinach according to the stage of production. By searching the international standards of pesticide residue limits in spinach, the status of standards for spinach and its product was analyzed. The dynamics of chlorpyrifos and other pesticide residues, transferring in spinach cultivation and processing was studied, and the theoretical maximum dietary intake （TMDI） of pesticides in Chinese spinach was also estimated. With the results of pesticide used in trial experiment and processing factor, some MRLs were proposed for raw spinach and its product. There are also some advices proposed for the pesticide limit establishment and pesticide control. The main conclusions of this study are as the following:The first, the status of pesticide residue limits for spinach was analyzed. There are different standards in different countries, and the quantities and ranges of MRLs are significantly diverse. There are about 321 MRLs for spinach in Japanese standard, however, the number of limit over 0.1 mg·kg^-1 is about 163, which accounts for 50% of the total. The results show that there is more space for China to meet the requirement of Japanese positive list system for spinach export. There are about 303 MRLs for spinach and its analogue in European Union, only 163 MRLs especial for spinach, and there are more than 259 MRLs under 0.05mg·kg^-1, which accounts for 85% of the total. The European Union standard is the mostly strict standard compared with others. The Codex Alimentarius Commission standard for spinach has about 78 MRLs, which is the less strict standard, and the number of limits under 0.1mg·kg^-1 is only 10 which accounts for 12.8% of the total. There are about 55 MRLs in American standards and the number of limits under 0.1mg·kg^-1 is 5% of the total, which is the least strict standard. In general, the strict degree of those standards is on the down order of EU, Japan, CAC and US. There is no herbicide limit for spinach in China, and the number is less than EU, Japan and US whose standards include pesticide, bactericide and herbicide, however. There was a long distance between spinach and its product in the variety and quantity of limits, and some advice were proposed to uniform the limits and judgement rule for Chinese spinach.Secondly, the dynamics of residues for chlorpyrifos and other pesticides during spinach cultivation and processing were studied. The residue of chlorpyrifos in soil could be uptaken by spinach, and the results showed that the quantity uptaken by root had a positive relationship with the residue in soil. So, before export enterprise planting spinach, the enterprise should affirm the pesticide residue in soil to avoid effecting spinach export. The results of pesticide residue dynamics in trial experiment showed that malathion had a more rapid degradation rate, the primary residue is only 4.5 mg·kg^-1 under the limit of 8 mg·kg^-1 for leafy vegetable in China. Chlorpyrifos was not proposed to be applied in spinach cultivation for insect control, because the existing limit is much stricter, not easy to achieve. There are no limits for propamocarb and metalaxyl in spinach, so is the other insecticide mixtures. The degradation and category of pesticide should be thought in the limits and safe intervals establishing. The residues of chlorpyrifos, fenvalerate and cypermethrin could be reduced by washing, blanching and drying so that exposure of residues via dietary intake could be reduced. The loss caused by frozen dry and hot air dry for pesticides in spinach had a relationship with solubility and vapor pressure, respectively. The loss of malathion during hot-air drying is more than 60%, however there is almost no loss during frozen dry for dimethoate in spinach. So different enterprises should use different pesticides based on their agro-product processing method to reduce the risk of pesticide.The third, the theoretical maximum dietary intake （TMDI） of pesticide in spinach was estimated for Chinese consumer. Dietary exposure assessment is the base for limit setting and risk management, and the risk index （%ADI） for 14 pesticides calculated by TMDI method was analyzed. The results showed that the risk index of synthetic pyrethroids was lower than organophosphorus pesticides, which is 12.2%-47.8%. However the index of dimethoate and diazinon is higher more than 243.6% and 121.8%, respectively, need to be further reduced by refined method. The MRL and pre-harvest interval is different, which was set by different methods. The EU method according with producing requirements is stricter compared with others.The MRL of chlorpyrifos, ?-cypermethrin, malathion, metalaxyl and propamocarb in spinach was 1,0.5,0.1,0.1 and 0.5mg·kg^-1 respectively, and the safe interval was 7,7,3,14 and 14 days respectively, calculated with the method of EU. The processing factor of pesticide was firstly used in MRL setting for dehydrated spinach, based on the processing factor of chlorpyrifos, cypermethrin, fenvalerate and malathion and their MRLs in raw spinach, the MRLs for those pesticides established in dehydrated spinach was 5,6,3 and 3 mg·kg^-1,respectively.Finally, some suggestions were proposed to set and control the pesticide residue limit in spinach and its product. The pesticides residue controlling and limit setting for spinach should be conducted in the whole with coherent, continuous and effective surveillance. The number of limit standards for spinach in different stages should be uniform, and there should be relevant values during the stage of soil, spinach planting and processing. The limit setting and conducting should be on the base of exposure assessment combined with agriculture practice and pesticide registration. All participants （producer, governor and consumer） need to be actively involved in the process of pesticide residue controlling for spinach which also need sound and effective laws and regulations.There are more active theoretical value and practical significance for pesticide residues controlling, limits setting and dietary exposure estimate in China, which are also significant to be used for the pesticide limit setting of other agro-products.更多还原