Metabolism of fenitrothion in red-backed voles (Clethrionomys gapperi)

To estimate the impact of fenitrothion on small mammals, a breeding colony of wild southern red-backed voles (Clethrionomys gapperi) was successfully maintained. The red-backed vole is a nontarget species inhabiting coniferous forests that are subjected to aerial spraying of the pesticide for the control of spruce budworm infestations. The voles were used to examine toxicity and the metabolic pathways involved in the elimination of fenitrothion after intraperitoneal injection of the purified, undiluted organophosphate. The 96-hr LD₅₀ was 1330 mg/kg. Toxicities toward males and females were not significantly different. All observed symptoms of intoxication and 99% of the mortality occurred within 48 hr of dose application. All major metabolites of fenitrothion metabolism in nonruminant mammals were identified and quantified by gas chromatography. At all doses, fenitrothion was rapidly metabolized and excreted. No body accumulation of residues was implied. The toxicity of fenitrothion was not correlated with increasing proportion of the dose converted into fenitrooxon. The low toxicity to red-backed voles is probably due, in part, to rapid metabolic detoxication by the two mechanisms cleaving fenitrothion at the P-O-aryl and PO-alkyl bonds, the latter becoming more prominent at high dose levels.     

吡虫啉、苯醚甲环唑和百菌清在甘蓝中的消解及残留分布

为明确吡虫啉、苯醚甲环唑和百菌清在露地甘蓝中的消解动态及残留分布规律,在田间施用农药后,采用液相色谱-质谱联用仪和气相色谱仪,对不同时间甘蓝样品及甘蓝不同部位的农药残留量进行了分析。结果表明:3种农药在甘蓝中的消解动态均符合一级反应动力学模型,其中,吡虫啉消解最快,苯醚甲环唑次之,百菌清最慢,半衰期分别为1.35、2.28和2.47 d。最终残留试验结果显示:施药后7和14 d,吡虫啉、百菌清在甘蓝中的残留量均符合食品中农药残留限量要求,而苯醚甲环唑在施药后14 d的残留量仍高于最大残留限量值 (MRL)。3种农药在甘蓝不同部位中的残留量差异显著 (P<0.05),其中甘蓝内球叶中未检出或残留量较低,外球叶中初始残留量较低,1至5 d可降至MRL值以下,外叶中的残留量显著高于其他部位。该结果表明,采后处理甘蓝时若去除其外叶,可有效降低甘蓝中的农药残留量,提高质量安全水平。     

The effects of temperature, humidity and rainfall on captan decline on apple leaves and fruit in controlled environment conditions

BACKGROUND: Captan is an important fungicide for controlling diseases in horticultural crops. Predicting its dissipation is important for estimating dietary risks and optimising pesticide application. Experiments were conducted to determine the relationship of captan loss on apple leaves with temperature, humidity and rainfall, and to investigate captan loss on fruit in dry conditions. RESULTS: There was large unit-to-unit variability in captan residues in spite of the controlled application. Temperature and humidity had negligible effects on captan loss. Captan loss is predominately due to washoff by rain, although a certain proportion of captan may bind to the plant surface tightly and hence may not be readily removed by rain. About 50% of captan can be washed off by as little as 1 mm of rain after an application, and the loss appeared not to relate to the amount of rain. Under dry conditions, daily loss of captan is estimated to be around 1% on both fruit and leaves, giving a half-life of ca 70 days. CONCLUSIONS: Captan loss on leaf and fruit surfaces is primarily due to rain washoff.     

氟环唑在小麦及土壤中的残留及消解动态

为了评价氟环唑在小麦生产上使用的残留安全性,建立了气相色谱-电子捕获检测器检测氟环唑在小麦植株、小麦籽粒及土壤中残留的分析方法,并对氟环唑在小麦植株、小麦籽粒和土壤中的最终残留量及小麦植株和土壤中的消解动态进行了研究。结果表明:在添加水平为0.01、0.1和2 mg/kg（小麦籽粒和土壤）和0.01、0.1和10 mg/kg（小麦植株）下,氟环唑的回收率为82%~93%,相对标准偏差为3.0%~9.7%。氟环唑在小麦植株、小麦籽粒和土壤中的定量限均为0.01 mg/kg。氟环唑在小麦植株和土壤中的消解半衰期分别为3.5~8.4和10~30 d。当以有效成分112.5 g/hm2的剂量施药2次、采收间隔期为21 d时,小麦籽粒中氟环唑的残留量为<0.05 mg/kg,低于中国制定的小麦中氟环唑的最大残留限量值（0.05 mg/kg）。建议氟环唑在小麦上使用时最大剂量为有效成分112.5 g/hm2,施药2次,安全间隔期为21 d。     

Residue levels of three organophosphorus insecticides in sweet pepper grown in commercial greenhouses

The degradation rates and residue levels of diazinon, pirimiphos-methyl and chlorpyrifos in the leaves and fruits of pepper plants grown in commercial greenhouses were studied using g.l.c. Analysis of leaves at intervals following application showed that the initial residue of diazinon was higher than that of the other two insecticides, while its dissipation rate was faster. The dissipation of chlorpyrifos in fruits was faster than diazinon. The maximum residue levels (m.r.l.) of diazinon (0.5 mg kg^?;1) and chlorpyrifos (0.1 mg kg^?;1) were reached after 13 and 8 days of application respectively. With diazinon and pirimiphos-methyl, sprayed 3 weeks before inflorescence, very low concentrations of both insecticides were found in fruits, although these compounds have no systemic behaviour. Chlorpyrifos residue level of 0-2 mg kg ^?;1 in harvested fruits did not drop below m.r.l. after 11 days holding period.     

硝磺草酮在甘蔗和土壤中的残留行为

建立了硝磺草酮在甘蔗和土壤中的残留分析方法,并在广东和广西分别进行了10%硝磺草酮悬浮剂在甘蔗上残留的田间试验,研究了硝磺草酮在甘蔗和土壤中的消解动态和最终残留量。样品用乙腈提取,盐酸调节pH至3~4后二氯甲烷萃取,采用高效液相色谱配二极管阵列紫外检测器(HPLC-PDA)检测。结果表明:在0.01、0.1和1 mg/kg 3个添加水平下,硝磺草酮平均添加回收率为82%~84%,相对标准偏差(RSD)为1.9%~3.4%,检出限(LOD)为0.005 mg/kg,定量限(LOQ)为0.01 mg/kg。田间试验结果表明:施用10%硝磺草酮悬浮剂后,在甘蔗上的残留量呈现先降低后升高又下降的趋势;在土壤中的半衰期为12.3~14.7 d,属于易降解农药。最终残留量测定结果显示:收获期甘蔗中硝磺草酮的残留量均0.01 mg/kg。     

Liquid and Gas Chromatographic Multi-residue Pesticide Determination in Animal Tissues

A liquid chromatography multi-residue method with photometric detection has been developed. The method is applicable to the quantitative determination of organochlorine (tetradifon, dicofol, chlorfenson, chlorobenzilate), organophosphorus (fenitrothion, azinphos-ethyl) and carbamate (pirimicarb) pesticides in animal tissues. The extracted residues are cleaned up by gel-permeation chromatography. A further fractionation on silica Sep-Pack cartridges is included in the procedure. A gas chromatographic method with electron-capture detection for the analysis of the same pesticides was carried out and the results in the two cases compared. Lower detection and quantitation limits and similar recoveries of pesticides from spiked pig liver and brain samples were obtained by the LC method. © 1997 SCI.     

Fungicide seed treatments to improve seedling emergence of perennial ryegrass Lolium perenne and the effect of different cultivars and soils

Seeds of perennial ryegrass Lolium perenne treated with four fungicides, benomyl, captan, iprodione and metalaxyl, used singly and in all combinations were sown in soil in pots. The soil was maintained at a low moisture content to predispose the seedlings to pre-emergence infection by soil-borne fungi. Thirteen of the fifteen fungicide treatments significantly increased seedling emergence and all but one contained benomyl and/or captan. In another pot experiment, a combination of benomyl and captan was tested against four similar treatments, carbendazim+captan, thiabendazole+captan, thiabendazole+metalaxyl and thiabendazole+thiram and also drazoxolon. Only benomyl+captan and drazoxolon did not increase seedling emergence significantly. A natural infection of the seedlings by powdery mildew Erysiphe graminis was reduced significantly by all treatments except thiabendazole+thiram and drazoxolon. Only car-bendazim+captan significantly increased the dry weight of seedlings per pot 98 days after sowing. Benomyl+captan seed treatment significantly increased seedling emergence in 9 of 16 soils collected from widespread sites. One perennial ryegrass cultivar, Parcour, was used in the above experiments and in a comparison with 12 other diploid cultivars its response to benomyl seed treatment was about mid-range.     

对氯苯氧乙酸钠在荔枝和土壤中的残留行为

建立了对氯苯氧乙酸钠在荔枝和土壤中的残留分析方法,并在广州和南宁进行了8%对氯苯氧乙酸钠可溶性粉剂在荔枝上残留的田间试验,研究了对氯苯氧乙酸钠在荔枝和土壤中的消解动态和最终残留量。样品用碱溶液提取,盐酸调节pH值至2.5后乙酸乙酯萃取,采用高效液相色谱二极管阵列紫外检测器(HPLC-PDA)检测。结果表明:在0.01、0.1和1 mg/kg 3个添加水平下,对氯苯氧乙酸钠在荔枝和土壤中的平均回收率为81%~85%,相对标准偏差(RSD)为1.9%~4.6%,检出限(LOD)为0.005 mg/kg,定量限(LOQ)为0.01 mg/kg。田间试验结果表明:8%对氯苯氧乙酸钠可溶性粉剂在荔枝和土壤中的半衰期分别为3.2~5.9 d和15.2~20.6 d,属易降解农药。最终残留量测定结果显示:8%对氯苯氧乙酸钠可溶性粉剂按有效成分20和30 mg/L分别施药2次,广州和南宁两地收获期荔枝中对氯苯氧乙酸钠的残留量均＜0.01 mg/kg。     

浸果处理后苯醚甲环唑在柑橘贮藏过程中残留量的变化

研究了贮藏期间柑橘中苯醚甲环唑残留量变化与浸果处理药液浓度、贮藏温度和贮藏时间的关系,以及果实不同部位残留水平的差异。柑橘经苯醚甲环唑药液浸泡处理后在常温或低温条件下贮藏,定期取样用丙酮-石油醚(3∶ 1,体积比)提取,气相色谱测定。当添加浓度范围为0.05 ~5.0 mg/kg时,本方法回收率在81.9% ~91.4%之间,相对标准偏差为5.3% ~17.5%,最低检出浓度为0.02 mg/kg。试验结果表明:柑橘中苯醚甲环唑残留水平与药液浓度呈正相关;低温贮藏下柑橘对苯醚甲环唑的吸收低于常温;苯醚甲环唑的残留水平随贮藏时间的延长而下降;橘皮中苯醚甲环唑的残留明显高于橘肉。建议10%苯醚甲环唑水分散粒剂的使用浓度为100 mg/L,其贮藏安全间隔期为21 d。     

丁虫腈在玉米和土壤中的残留及消解动态

建立了丁虫腈在土壤、玉米植株及玉米籽粒中残留的气相色谱分析方法。玉米植株和籽粒样品用乙腈提取,经Oasis HLB固相萃取柱净化;土壤样品用丙酮提取,经液-液萃取净化,气相色谱-电子捕获检测器(GC-ECD)检测,外标法定量。结果表明:在0.01、0.05和0.5 mg/kg 3个添加水平下,丁虫腈的回收率为80%~86%,相对标准偏差(RSD)为5.1%~8.0%;其在土壤、玉米植株及籽粒中的定量限(LOQ)均为0.01 mg/kg。采用所建立的方法对丁虫腈在玉米和土壤中的残留及消解动态进行研究的结果表明:丁虫腈在土壤和玉米植株中的半衰期分别为6.77和2.44 d。采用5%的丁虫腈乳油按推荐高剂量(有效成分)37.5 g/hm2及其1.5倍该剂量(56.25 g/hm2)于玉米苗后茎叶初期施药1次,在玉米乳熟期和成熟期时,玉米籽粒中丁虫腈的最终残留量均低于定量限;玉米收获时(距施药90 d),籽粒中丁虫腈的残留量均低于参考的MRL值(0.02 mg/kg,氟虫腈在谷物中的最大残留限量)。     

醚菌酯和腐霉利在温室草莓中的残留行为及其膳食摄入风险评估

为明确醚菌酯和腐霉利在温室条件下在草莓中的残留行为及其可能产生的膳食摄入风险,于2012—2013年在北京的日光温室进行了醚菌酯和腐霉利喷施草莓的3次田间农药残留试验,建立了一种快速、简便的气相色谱-质谱联用检测草莓果实中农药残留量的方法,并对不同人群的膳食暴露及风险进行了评估。草莓样品经乙腈提取,PSA(乙二胺-N-丙基硅烷)净化,采用气相色谱分离,四极杆质谱检测,外标法定量。结果表明:醚菌酯和腐霉利在温室草莓中的消解均符合一级动力学方程,醚菌酯为c=0.804 7e-0.114t,R2=0.935 6,半衰期为6.1 d;腐霉利为c=3.283 9e-0.098t,R2=0.927 9,半衰期为7.1 d。当醚菌酯有效成分用量为97.5和195 g/hm2,腐霉利有效成分用量为375和750 g/hm2时,喷药2次和3次,施药间隔期7 d,于末次喷药后1、2、3和5 d采收草莓,其残留量分别在0.09~1.52和0.12~5.81 mg/kg之间。两种药剂的最终残留量均不超过我国规定的最大残留限量(MRL)标准。膳食暴露慢性和急性风险评估结果表明:施药后1~5 d采收的草莓中,醚菌酯和腐霉利对2~6岁、7~14岁、18~30岁和60~70岁的男、女共8类不同人群的膳食摄入风险均在可接受范围之内。     

三甲基硅重氮甲烷衍生化-气相色谱法测定水果蔬菜中乙烯利的残留

针对水果蔬菜中乙烯利的残留,建立了三甲基硅重氮甲烷衍生化-气相色谱的分析方法。样品用 V (甲醇) : V (盐酸) = 9:1的溶液提取,无水乙醚萃取,三甲基硅重氮甲烷衍生化15 min,采用气相色谱-质谱法定性,气相色谱仪-火焰光度检测器 (GC-FPD) 检测,外标法定量。结果显示:在0.01~2 mg/L范围内,乙烯利的质量浓度与其对应的峰面积间线性关系良好,相关系数大于0.999 6;此方法检出限为0.01 mg/kg,定量限为0.03 mg/kg;在辣椒、番茄、香蕉、苹果和梨的空白果蔬样品中分别添加0.01、0.1和1 mg/kg 3 个水平下,回收率为93%~102%,相对标准偏差为4.2%~7.3%。该方法准确度和灵敏度高,抗干扰能力强,能准确并快速测定出水果、蔬菜中乙烯利的残留量。     

Organophosphorus insecticide residues in olives and olive oil

In order to check the pre-harvest intervals established in Portugal for olive trees, residue dissipation studies have been carried out for the organophosphorus insecticides diazinon, dimethoate, methidathion, parathion and phosphamidon. Simul-taneously with the analyses of the olives, olive oil produced in the laboratory by a mechanical procedure of pressing the olives was also analysed. The analyses were car- ried out by gas-liquid chromatography. Residues found in the fresh olives, sampled at the end of pre-harvest intervals in force for each of the insecticides, were accept able. However, for diazinon and parathion, unacceptable high residue levels were found in the olive oil. The concentration of methidathion residues in the olive oil was also observed. For dimethoate and phosphamidon, no detectable residues were found in the olive oil, even when the olives were sampled one day after spraying.     

黄瓜中醚菌酯的残留及风险评估

建立了醚菌酯在黄瓜中的残留分析方法,并在广州和天津进行了30%醚菌酯可湿性粉剂在黄瓜上残留的田间试验,研究了醚菌酯在黄瓜上的消解动态和最终残留,采用风险商值法对黄瓜中醚菌酯可能产生的膳食风险进行了评估。黄瓜样本用乙腈提取,高效液相色谱-串联质谱法(HPLC-MS/MS)检测。在添加水平为0.01、0.05和0.5 mg/kg时,平均添加回收率在91%～95%之间,相对标准偏差为3.74%～9.99%,检出限(LOD)为0.001 mg/kg,定量限(LOQ)为0.01 mg/kg。田间试验结果表明,醚菌酯在广州和天津黄瓜中的半衰期分别为1.5 d和2.1 d,消解迅速,施药3 d后最终残留量为0.08～0.23 mg/kg,施药5 d后最终残留量均低于LOQ值。风险评估结果表明,施药后3 d时黄瓜中醚菌酯的残留风险商值均远远低于1。表明喷施30%醚菌酯可湿性粉剂防治黄瓜白粉病,按照推荐剂量使用对人体健康是安全的。     

Gel filtration clean-up for multi-residues of organophosphorus pesticides in rice

Gel filtration on Bio-Beads S-X8 and Sephadex LH-20 columns has been successfully applied to the clean-up of multiple residues of malathion, fenitrothion and dichlorvos in rice. Recoveries were checked by gas-liquid chromatography using CsBr-thermionic detector and ranged from 77 to 104% at 5 mg/kg level. The clean-up was found to be highly effective. No interference was observed in the gas chromatograms.     

毒死蜱在梨果实不同部位的残留及消解动态

为探明毒死蜱在梨果实不同部位的残留及消解规律,以20 a生鸭梨（Pyrus bretschneideri Rehd.cv.Yali）为试材,于果实生长期在套袋后向整株喷施48%毒死蜱乳油500倍液（有效成分960 mg/L）,分析毒死蜱向果实中的运输及分配规律;于果实成熟期在采收前向果面喷施48%毒死蜱乳油1 000倍液（有效成分480 mg/L）,分析采后毒死蜱在梨果实不同组织中的分布特征。采用乙腈萃取和GC-NPD检测方法,测定不同处理试材中的毒死蜱含量。结果表明,在果实套袋情况下,整株喷施毒死蜱后72 h内果实不同部位（果心除外）毒死蜱含量均呈现先逐渐上升而后下降趋势,其中果柄、果皮和果梗洼中毒死蜱最高含量值及其出现的时间分别为6.66 mg/kg（12 h）、2.42 mg/kg（24 h）和0.09 mg/kg（12 h）,表明套袋果实毒死蜱来源于枝叶运输,经果柄进入果实后易向果皮累积;而未套袋果施药后24和72 h果皮中毒死蜱含量分别为套袋果的12.56和7.29倍,表明套袋可有效降低果实中毒死蜱的残留量。于果实成熟期向果面喷施毒死蜱后7、14和25 d,果皮中毒死蜱残留量分别为15.54、13.70和12.81 mg/kg,占全果含量的100%,而果肉中毒死蜱残留量低于本检测方法的最低检出浓度（0.05 mg/kg）,因此果皮为果实中毒死蜱主要残留部位,且贮藏期果皮中毒死蜱不易向果肉扩散。     

Influence of formulation on spray deposit patterns,dislodgeable and penetrated residues,and persistence characteristics of fenitrothion in conifer needles

The influence of formulation on spray droplet spectra, deposit patterns, dislodgeable and penetrated residues, and persistence characteristics of fenitrothion in balsam fir needles was studied using three formulations containing different types of adjuvant. Spray was applied on to potted trees under controlled conditions in a laboratory chamber. Droplet size spectra and deposits were assessed using “Kromekote” cardlglass plate units. Foliar residues were measured by gas-liquid chromatography. The formulation containing polymeric adjuvants provided significantly larger droplets and higher foliar residues than those containing surfactants and co-surfactants. It also provided a higher ratio of dislodgeable-to-penetrated residues, and a slower initial rate of loss of fenitrothion. None of the formulations posed a long-term persistence problem because only very low amounts remained on foliage at 42 days post-treatment. The significance of these findings in terms of the possible increase in bioavailability of the pesticide via crawling contact is discussed.     

叶菌唑在小麦中的残留消解及膳食风险评价

为评价叶菌唑在小麦中的残留行为及其产生的膳食摄入风险,于北京、安徽及黑龙江进行了1年3地田间试验,建立了叶菌唑在小麦中的残留分析方法,并对我国不同人群的膳食暴露风险进行了评价。样品用乙腈提取,经Florisil固相萃取柱净化,气相色谱-氮磷检测器(GC-NPD)检测,外标法定量。结果表明:在0.02~10 mg/kg的添加水平下,叶菌唑在小麦籽粒和植株中的平均回收率在81%~101%之间,相对标准偏差(RSD)在2.1%~9.1%之间;其在小麦籽粒和植株中的定量限(LOQ)分别为0.02和0.04 mg/kg。叶菌唑在小麦植株中的消解符合一级动力学方程,半衰期为4.9~7.3 d。收获时小麦籽粒中叶菌唑的最大残留量为0.037 mg/kg,低于美国和欧盟设定的最大残留限量(MRL)0.15 mg/kg。针对我国不同人群的膳食摄入及风险评估暴露,风险商值(RQ)在0.001~0.002之间,表明叶菌唑在小麦中的膳食摄入风险较低。     

作物和土壤中乙酰甲胺磷及其代谢物甲胺磷消解研究

为评价乙酰甲胺磷在作物上使用的安全性,采用气相色谱法研究了不同气候条件(亚热带和暖温带)下的4种作物(甘蓝、萝卜、水稻、柑桔)和8个土壤样品(4种作物各自在两个试验地点的土壤)中乙酰甲胺磷及其代谢物甲胺磷的消解情况。结果表明:乙酰甲胺磷在作物和土壤中均可代谢产生甲胺磷,作物中的2 h甲胺磷代谢产率主要由作物种类决定。作物中乙酰甲胺磷的消解半衰期为3.1~13.5 d,甲胺磷为2.7~12.8 d;土壤中乙酰甲胺磷的半衰期为1.4~6.4 d,甲胺磷为4.5~10.7 d。土壤pH值对乙酰甲胺磷的消解影响显著,其在碱性土壤中消解较快。具有较高净辐射的气候条件会促进乙酰甲胺磷及甲胺磷在作物中的消解,因此种植在暖温带气候条件下的作物上使用乙酰甲胺磷较种植在亚热带气候条件下的具有更高的甲胺磷残留风险。乙酰甲胺磷施用在叶菜类蔬菜上可能会有较高的甲胺磷残留风险,建议叶菜类蔬菜应谨慎使用乙酰甲胺磷。