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自2018年《CNAS-GL006化学分析中不确定度的评估指南》颁布后,不确定度计算方法的需求日益增强。本研究依据GB 23200.8-2016《水果和蔬菜中500种农药及相关化学品残留量的测定气相色谱-质谱法》,采用气相色谱-质谱法,结合内标定量法,对草莓中丙溴磷、亚胺硫磷、五氯硝基苯和氯氟氰菊酯的残留进行了测量不确定度的详细评定,共涉及标准品纯度、储备液配制、工作液配制、称样量和前处理过程5个B类评定分量,以及标准溶液峰面积、样品溶液峰面积和添加回收率3个A类评定分量。结果显示:在0.08 mg/kg添加水平下,丙溴磷、亚胺硫磷、五氯硝基苯和氯氟氰菊酯的测量合成相对标准不确定度依次为3.55%、3.22%、2.20%和3.66%,样品溶液峰面积和添加回收率2个A类不确定度分量对4种农药合成不确定度的贡献较高,其中丙溴磷、亚胺硫磷和氯氟氰菊酯均超过60%,五氯硝基苯超过31%。本研究中4种农药在草莓样品中的测量结果在95%的置信限(k=2)内可表示为:丙溴磷,0.085±0.006 mg/kg;亚胺硫磷,0.084±0.005 mg/kg;五氯硝基苯,0.079±0.003 mg/kg;氯氟氰菊酯,0.082±0.006 mg/kg。不确定度评定结果将最大限度地减少待测物在最大残留限量附近的残留值判定可能存在的争议。 相似文献
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为了解人参不同部位中农药残留分布规律及膳食风险,分别取黑龙江省鸡东市2、3、4年参,虎林市2、3、4、5、6年参,针对其芦头、主根及须根建立了气相色谱-质谱联用(GCMS)检测技术,分别测定了其中五氯硝基苯、六氯苯及毒死蜱的残留量,并就人参中3种农药残留的短期膳食风险进行了评估。72份人参样品中,五氯硝基苯检出率为74%,检出残留量在0.005~0.062 mg/kg之间;六氯苯检出率为78%,残留量在0.057~0.150 mg/kg之间;毒死蜱检出率为61%,残留量在0.018~0.073 mg/kg之间。2020版《中国药典》规定人参中五氯硝基苯和六氯苯的最大允许残留限量(MRL)均为0.1 mg/kg,所检测样品中,虎林市5、6年参芦头及6年参主根中六氯苯的残留量超过了该限量标准,超标率分别为2.8%、5.6%和2.8%。总体而言,农药残留水平随人参种植年份的增加而升高,人参各部位中累积的农药残留量由高到低分别为芦头>主根>须根,同时其短期膳食风险商(RQST)远小于100%,说明通过人参摄入的农药残留对人体不会产生不可接受的短期膳食暴露风险。 相似文献
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茄子在育苗过程中,由于低温、高湿易发生猝倒病。 防治此病,用土壤杀菌剂—五氯硝基苯进行苗床土壤处理,成本低(0.18元/亩),方法简便,效果好,深受菜农欢迎。 相似文献
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猝倒病是棚室瓜类苗期的主要病害 ,蔓延快 ,危害重。主要症状表现为 :幼芽出土后胚茎基部或中部呈水渍状 ,后变为黄褐缢颈 ,子叶尚未凋萎而猝倒 ,或胚芽和叶便已变褐腐烂 ,甚至病苗残体及附近土表长出一层白色絮状物。猝倒病的发生与土壤消毒不严、低温多湿、通风不良、光照不足 ,以及高脚苗等有关。其综合防治要点如下 :1 苗床选择苗床应选择地势高燥 ,排水良好 ,或未种过瓜类作物。2 土壤消毒每m3 营养钵土用 4 0 %五氯硝基苯 12 5mg或每m2 苗床用 5kg干土拌入五氯硝基苯 9g 70 %代森锰 1g盖籽 ,或播种前 2 ,3周用福尔马林密… 相似文献
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浙八味中药材中农药残留调查及控制对策 总被引:1,自引:0,他引:1
通过对浙八味主产区的调查.发现有些中药材依然受到土壤中的滴滴涕、六六六农药残留的污染.麦冬中滴滴涕(或同系物)残留量较高,主要因过去曾长期、大量使用滴滴涕、六六六,导致种植麦冬的部分土壤中滴滴涕(或同系物)残留量仍较高(最高达1.6mg/kg);在部分中药材和土壤中检测出痕量的六六六残留.仙居白术2个样品和土壤中五氯硝基苯的残留较高,其他部分中药材中检测到很低量的毒死蜱、违禁高毒有机磷农药甲胺磷、氯菊酯等农药残留.除了滴滴涕、六六六外,造成中药材中其他农药残留的原因均为药农违规使用农药. 相似文献
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The disappearance of quintozene (I) and its technical impurities and metabolites pentachlorobenzene (III), hexachlorobenzene (IV) and pentachloroaniline (V) from soil, was studied in laboratory experiments under controlled conditions during a period of about 600 days. The very high persistence found, was confirmed by the analysis of 22 samples collected from fields used for potato growing and treated regularly during the foregoing 11 years with commercial formulations of quintozene. In the laboratory experiments, III, V and methylthiopentachlorobenzene (VI) were found to be degradation products from the quintozene. 相似文献
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The build-up and decline of quintozene and hexachlorobenzene residues in protected lettuce, resulting from one to five treatments of the soil (each of 35 g m-2) with a quintozene formulation, have been studied. Residue levels were monitored in each experimental crop during growth until harvest. Residues in the soil at harvest were also determined. Quintozene residues in the harvested lettuce were in the range < 0.02–0.80 mg kg?1 and those of hexachlorobenzene were in the range < 0.02–0.05 mg kg?1 (expressed on a fresh weight basis). Residue levels in the soil were 5.4–231 mg kg?1 for quintozene, and 0.20–5.4 mg kg?1 for hexachlorobenzene (expressed on a dry weight basis). Under the experimental conditions of the trial there was no significant build-up of quintozene or hexachlorobenzene in harvested lettuce, even after five treatments to the same site. 相似文献
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Hans R. Kataria Jaipal S. Yadav Faquir C. Garg Rajendra K. Grover 《Pest management science》1985,16(4):337-340
2-Methoxyethylmercury chloride (MEMC) applied to cowpea seeds with Rhizobium provided little or no control of seedling rot caused by Rhizoctonia solani; similar treatment, but without Rhizobium, gave >40% control of disease. Treating seeds with quintozene and then with Rhizobium rendered the fungicide completely ineffective against R. solani infections; disease control was >70% when seeds were treated with quintozene only, and >60% when seeds were coated first with Rhizobium and then with quintozene; treatment with quintozene+Rhizobium gave about 25% control. Simultaneous treatment with Rhizobium considerably reduced the efficacy of captafol, chloroneb, carbendazim and thiophanate-methyl. Disease control by carboxin, benomyl and thiabendazole remained unaltered in the presence of Rhizobium, but only thiabendazole gave good control. Seeds treated with MEMC and Rhizobium produced seedlings without root nodules; nodulation was also decreased by captafol and by carboxin but six other fungicides had no effect. The implications of Rhizobium-fungicides interactions are discussed in the context of fungicidal control of root diseases. 相似文献
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Coating iris bulbs with a preparation ofTrichoderma harzianum was highly effective under greenhouse conditions in reducing incidence of diseases caused byRhizoctonia solani andSclerotium rolfsii. In field experiments with irises for bulb production, the incidence ofR. solani in plants and bulbs was effectively reduced (up to 93%), and the yield increased (by 35–41%), by applyingT. harzianum either as a bulb coating or broadcast application (biological treatment), treating soil with pentachloronitrobenzene (PCNB; quintozene) (chemical treatment), or solarizing the soil by mulching it with transparent polyethylene sheets (physical treatment) prior to planting. Combined treatments,i.e., chemical-biological or physicalbiological, were the most effective.T. harzianum bulb treatment and broadcast application in field plots increasedTrichoderma population density in the soil by 4–27 times. 相似文献
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植物病原真菌对甲基立枯磷的抗药性及风险研究 总被引:5,自引:2,他引:3
通过对人工获得的抗甲基立枯磷菌株的抗药水平、在培养基上的生长速度、致病力、对其它杀菌剂的敏感性测定以及对菌核的观察和用药条件等方面分析, 在实验室内进行了植物病原真菌对甲基立枯磷的抗药性风险研究。结果显示, 不同的病原菌具有不同的抗药性。抗甲基立枯磷的水稻纹枯病菌菌株对甲基立枯磷的抗药性较强、抗药性风险大; 小麦纹枯病菌和油菜菌核病菌抗药菌株抗药性较弱、风险小。抗甲基立枯磷的水稻纹枯病菌对菌核净具有高水平正交互抗性; 抗甲基立枯磷的小麦纹枯病菌对菌核净和扑海因有中等程度正交互抗性; 这两种真菌的抗药菌株对五氯硝基苯的正交互抗性弱, 对烯唑醇和异稻瘟净没有交互抗性。甲基立枯磷与二甲酰亚氨类和芳烃类杀菌剂具有相似的抑菌作用。 相似文献
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The herbicides fluchloralin and alachlor applied to soil altered the effectiveness of fungicide treatments to seed and soil for controlling cowpea damping-off. These herbicides also modified the in-vitro toxicity of the fungicides to the mycelial growth of Pythium butleri and Rhizoctonia solani in a nutrient medium. Both herbicides reduced the toxicity of 2-methoxyethylmercury chloride (MEMC) and propamocarb to the growth of P. butleri, and of carbendazim to the growth of R. solani, but enhanced the toxicity of captafol and quintozene to P. butleri and R. solani, respectively. In pot tests, quintozene gave better control of R. solani damping-off in soil treated with fluchloralin or alachlor than in untreated soil, whereas disease control by carbendazim was decreased in similarly treated soils. Both herbicides attenuated the effectiveness of MEMC and captafol to control the damping-off caused by P. butleri; the efficacy of propamocarb was increased by alachlor but was decreased by fluchloralin. The implications of herbicide-fungicide interactions are discussed in the context of fungicidal control of root diseases in herbicide-treated soil. 相似文献
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Treatment of different soils with quintozene at a level of 1000 parts/106 and incubation for 24 days at 30 °C did not result in the formation of polychloroazobenzenes, although pentachloroaniline was formed. This negative finding is in line with previous work, where it was shown that azobenzenes can only be formed from substituted anilines with at least one free ortho position. Soil activity was demonstrated by incubation of 3,4-dichloroaniline under similar conditions yielding the expected 3,3′,4,4′-tetrachloroazobenzene. Mass fragmentography with a quadrupole mass spectrometer was used for the detection of polychloroazobenzenes. Mass spectra for the synthesised reference compounds are presented. 相似文献
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草地贪夜蛾Spodoptera frugiperda是一种世界性重大农业害虫,在全球多个国家普遍发生,其幼虫可为害玉米、水稻等多种农作物。该虫于2019年初入侵我国,对我国农业生产构成了严重的威胁,防控形势严峻。为寻求一种草地贪夜蛾的绿色防控方法,本文对草地贪夜蛾潜在RNA干扰(RNA interference,RNAi)靶标致死基因、RNAi传统双链RNA(double-stranded RNA,dsRNA)递送技术的瓶颈以及纳米载体介导的RNAi技术应用进行概括,并对纳米载体介导的RNAi技术应用前景进行展望。 相似文献