一项农药残留快速检测技术通过专家鉴定

本刊讯由中国农业大学资源与环境学院李季伦教授主持的“一种新型农产品农药残留快速检测技术的引进”项目最近通过验收。专家们一致认为:该项目通过引进国外技术及消化吸收,构建了农药残留快速检测技术研发平台,自主制备了对硫磷、甲基对硫磷、克百威、甲萘威等4种农药的抗体;开发出了对硫磷、甲基对硫磷和克百威的酶联免疫检测试剂盒以及克百威的检测试纸条。试剂盒检测时间为60～90min;试纸条检测时间少于5min;检测费用均低于10元/次。目前,该产品已小批量推向了市场。一项农药残留快速检测技术通过专家鉴定     

两种表面活性剂对土吸附苯酚的影响

表面活性剂对旱地土壤吸附有机污染物可以产生重要影响。用吸附平衡法,研究在阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)和阴离子表面活性剂十二烷基磺酸钠(SDS)共存条件下,苯酚在土中的吸附特征。结果表明:20℃和40℃下,在CTMAB共存条件下,土样对苯酚的吸附能力有明显提高,且随CTMAB浓度增加而增大,表现为0.01 mol/L CTMAB>0.005 mol/L CTMAB>0.002 5 mol/L CTMAB>CK。温度升高,随着CTMAB浓度增加,土对苯酚的吸附由增温正效应向增温负效应转变;在SDS共存条件下,在苯酚平衡浓度较低时,两个温度下不同SDS共存浓度对土吸附苯酚的影响差异不大,且低于CK。随苯酚平衡浓度增大,各浓度SDS处理土对苯酚的吸附开始时均显著增大并超过CK,最终吸附量趋于接近。随SDS浓度的增加,土对苯酚的吸附也由增温正效应向增温负效应转变。     

两性修饰膨润土对苯酚吸附的动力学研究

以两性表面活性剂十八烷基二甲基甜菜碱(BS-18)为修饰剂,制得两性修饰膨润土,研究了不同修饰比例、温度及pH值等条件下,两性修饰土对苯酚的吸附反应和动力学特征,并对吸附机制进行探讨。结果表明,不同修饰比例的两性修饰土对苯酚的吸附速度参数均大于未修饰膨润土,且均随着修饰比例的增加而增大,表明修饰可以显著加快膨润土对苯酚的吸附速率;低温有利于吸附;吸附量在pH 4~8的范围内较稳定,pH大于8后,吸附量迅速降低。两性修饰土对苯酚的吸附动力学曲线符合伪二级动力学模型。     

有机改性膨润土对乙草胺的吸附与控制释放作用

首次尝试将十六烷基三甲基铵盐阳离子改性的有机膨润土(CTMAB-Bents)用作乙草胺的吸附剂和控制释放载体。结果表明,与原土(Na-Bent)相比,CTMAB-Bents对乙草胺的吸附能力提高3~5倍,且吸附能力与改性膨润土所用CTMAB量成正相关。吸附等温曲线符合Freundlich经验方程,相关系数R>0.99,吸附能力主要取决于乙草胺在水和有机膨润土间的分配作用。与Na-Bent相比,CTMAB-Bents可以显著抑制乙草胺的释放速率,对乙草胺的半数释放时间(t50)介于20CTMAB-Bent制剂的6.57 h与100CTMAB-Bent制剂的19.0 h之间,并随改性膨润土对乙草胺吸附能力的提高而延长。释放动力学曲线符合Ritger和Peppas方程,n值(0.429~0.618)接近Fickian扩散模型,说明乙草胺在有机膨润土中的释放主要受到扩散控制。     

生物组织中多种农药成分的GC/MS分析

本文介绍了对多种农药中毒死亡者体内样品进行检验的方法。组织样品经过液-液萃取及GC／MS检测,从胃组织样品中检出了敌敌畏、克百威、毒鼠强、甲基对硫磷、敌百虫、氯氰菊酯、甲胺磷、马拉硫磷等8种农药残留,并检出甲基对硫磷的代谢产物甲基对氧磷;肝组织、血液样品均检出敌敌畏、克百威、毒鼠强、甲基对硫磷、敌百虫、甲胺磷等6种成分。本文在生物样品中同时检出多种不同极性的残留农药．为在刑事技术领域内毒物的检测、代谢和分布提供了一定的经验及实验数据。     

Degradation and Leaching of Carbofuran and Dimethoate in Terrestrial Soil-Core Microcosm

通过陆生微宇宙土芯淋溶试验研究克百威、乐果在常州水稻土和海安高砂土2种土壤中的降解和淋溶特性。结果表明：在整个实验周期,克百威、乐果在高砂土、水稻土不同土层中的含量依次为0～10〉10-30〉30～60cm;施药后2h淋溶,2种农药在水样中的检出浓度均较高：就2种农药对比而言,乐果在淋溶水样中浓度降低较为迅速,14d时淋溶水样中就未检出。而克百威在14d时仍有检出。受试农药的理化性质、降解特性及受试土壤的理化性等因素能很好地诠释试验结果。研究一方面可为这2种农药的科学使用提供参考,另一方面．为陆生微宇宙系统的开发、应用提供借鉴。     

美国限用更多农药以保护鱼类

考虑到部分农药对四个州濒临灭绝鲑鱼的风险,经与美国国家海洋渔业局（NMFS）磋商后,美国EPA决定限制使用第2批农药。按照NMFS 2009年4月份的生物学评价（BiOp）,EPA计划限用甲萘威、克百威和灭多威3种氨基甲酸酯类杀虫剂。     

吐鲁番棕漠土对~(14)C—六六六的吸附研究

很多实验资料表明,农药在土壤中的生物活性与土壤对农药的吸附紧密相关。一般说来,土壤对农药的吸附量增加时,农药的生物毒性就降低。本实验研究了吐鲁番棕漠土的颗粒大小、pH值、含水量及温度等因子对吸附六六六的影响,摸拟了棕漠土对六六六的吸附能力,为评价该地区土壤中有机氯农药的残留,为综合治理措施提供科学依据。     

有机膨润土对农药水乳剂稳定性的协同作用及其机制

以螺环菌胺水乳剂为例,在水乳体系中添加不同质量分数的有机膨润土,从水乳剂微观形态、药液表面张力、流变学特性及有机膨润土对螺环菌胺的吸附作用几方面,初步探讨了有机膨润土对水乳剂稳定性的协同作用及其机制。结果表明:有机膨润土的加入降低了水乳剂粒子的粒径,同时使粒径分布变窄,在微观上改善了水乳剂的稳定性;降低了药液的表面张力,起到了固体乳化剂的作用;在增大体系黏度的同时使其变成了可剪切变稀流体,增强了水乳剂体系的流变学特性,使其具有触变性;有机膨润土对螺环菌胺具有一定的吸附作用。上述因素共同作用的结果使得有机膨润土对农药水乳剂体系的稳定性产生了协同作用。     

克百威、乐果在陆生微宇宙土芯中的降解和淋溶研究

通过陆生微宇宙土芯淋溶试验研究克百威、乐果在常州水稻土和海安高砂土2种土壤中的降解和淋溶特性。结果表明:在整个实验周期,克百威、乐果在高砂土、水稻土不同土层中的含量依次为0~1010~3030~60cm;施药后2h淋溶,2种农药在水样中的检出浓度均较高;就2种农药对比而言,乐果在淋溶水样中浓度降低较为迅速,14d时淋溶水样中就未检出,而克百威在14d时仍有检出。受试农药的理化性质、降解特性及受试土壤的理化性等因素能很好地诠释试验结果。研究一方面可为这2种农药的科学使用提供参考,另一方面,为陆生微宇宙系统的开发、应用提供借鉴。     

Action of pesticides on earthworms. Part I: The toxicity of cholinesterase-inhibiting insecticides to earthworms as evaluated by laboratory tests

The action of seven cholinesterase-inhibiting pesticides [aldicarb, carbaryl, carbofuran, oxamyl, paraoxon (diethyl 4-nitrophenyl phosphate) parathion and trichloronate], the organochlorine insecticide, gamma-HCH, and the nematicide potassium N-hydroxymethyl-N-methyl(dithiocarbamate) (PHMD) on four earthworm species was investigated by laboratory toxicity tests. Eisenia foetida was the most tolerant species to the pesticides tested. Aldicarb was the most toxic pesticide to this species, causing severe dehydration prior to death or at sublethal concentrations. Aldicarb was also toxic to the other species (Allolobophora caliginosa, A. chlorotica and Lumbricus rubellus), while oxamyl, the other oxime carbamate, was not toxic to any of them. Carbaryl and carbofuran at low concentrations were lethal to A. caliginosa, A. chlorotica and L. rubellus, but E. foetida could tolerate high concentrations without dying, although low concentrations severely affected its ability to work the soil or to disappear from the soil surface. Paraoxon, parathion, trichloronate and gamma-HCH were moderately toxic with low lethal effect to all species. The ability to work the soil was moderately affected by parathion, trichloronate and gamma-HCH. PHMD was toxic to all the species. The lethal and non-lethal effects of the pesticides are discussed in relation to their possible biochemical mode of action in earthworms, and the data are compared with published information from field trials.     

Adsorption of systemic pesticides on ground stems and in the apoplastic pathway of stems,as related to lignification and lipophilicity of the pesticides

The adsorption of five systemic fungicides (carbendazim, triadimefon, nuarimol, triarimol, and fenarimol) and one herbicide (fluometuron) on ground stems and in the apoplastic pathway of excised pepper, cotton, and bean stems was studied. Adsorption on ground and water extracted stems, as well as retention in the apoplast of excised stems, increased with the 1-octanol/water partition coefficients of the pesticides. Methylation of ground stems increased their adsorption capacity (carbendazim excluded), while extraction with organic solvents did not affect it. Woody stems adsorbed more of the pesticides than herbaceous ones. Binding of pesticides in the apoplastic pathway of stems seems to be related to their degree of lignification and to the lipophilicity of the pesticides.     

基于荧光探针技术检测30种农兽药及其二元、三元组合对CYP3A4酶的联合毒性

在农业生产中混合使用多种农药或兽药越来越普遍,但因药剂联合毒性效应的不确定性而对人体健康产生严重威胁。本文基于酶抑制法原理,利用荧光探针 NEN (N-乙基-1,8-萘二甲酰亚胺) 直接检测CYP3A4酶的活性,建立了广谱筛查混合农兽药联合毒性效应的方法,并以常用的30种农兽药及其典型的23种二元和26种三元组合为研究对象,检测了农兽药混合物对CYP3A4酶的联合毒性效应,其中标准质量浓度根据食品安全国家标准规定的农兽药最大残留限量确定。结果表明:3种质量浓度梯度下对CYP3A4酶均具有协同作用的混合农兽药组合有克百威 + 多菌灵、克百威 + 吡虫啉、啶虫脒 + 烯酰吗啉、吡虫啉 + 多菌灵、氯氰菊酯 + 啶虫脒 + 烯酰吗啉、克百威 + 啶虫脒 + 多菌灵、吡虫啉 + 啶虫脒 + 多菌灵、吡虫啉 + 啶虫脒 + 烯酰吗啉、毒死蜱 + 啶虫脒 + 多菌灵和联苯菊酯 + 啶虫脒 + 多菌灵。当单一农兽药对CYP3A4酶活性的抑制率较高时,与其他农兽药混合后联合毒性效应呈拮抗作用,而当单一农兽药对酶活性的抑制率低于2%时,则与其他农兽药混合后联合毒性效应呈现不确定性。农兽药组合在低浓度下对CYP3A4酶的联合毒性往往存在较强的协同作用,但随着浓度的升高,联合毒性效应从协同变为拮抗作用。分析农兽药与CYP3A4酶之间的构效关系可知,含有芳氯基团的数量与对酶活性的抑制程度成正相关,含有3个芳氯及以上基团的农兽药对CYP3A4酶活性的抑制作用最为显著,抑制率在30%以上,如百菌清、毒死蜱、甲基毒死蜱、咪鲜胺等;含有2个芳氯或“强吸电子基团 + 1个芳氯”基团的农兽药,对CYP3A4酶活性的抑制作用较强,抑制率在18%以上,如苯醚甲环唑、哒螨灵和异菌脲等。具有氨基甲酸酯基团的农兽药单独作用于CYP3A4酶毒性较小或几乎没有毒性时,与其他农兽药混合后显示较强的协同作用。本研究建立的检测方法为广谱筛查混合农兽药联合毒性提供了新思路,检测结果可为进一步在细胞和动物水平制订农兽药混剂的风险评估方案提供依据。     

Rapid in vitro screening assay for immunotoxic effects of organophosphorus and carbamate insecticides on the generation of cytotoxic T-lymphocyte responses

There has been an increasing need for rapid and easily interpreted techniques for the screening of possible immunotoxicants. Besides the obvious detrimental effects of exposure to immunosuppressive agents, the modulation of the immune system which results from exposure to these toxicants may be a sensitive index to the toxicologic effects of such agents. Other researchers have proposed assays to screen the effect of in vitro treatment with immunotoxicants on mitogenic and humoral immune responses. In this report, we have described an in vitro technique for screening the effect of immunotoxicants, in the presence and absence of a NADPH fortified liver postmitochondrial supernatant (S-9) from Arochlor 1254-treated rat, on another aspect of the mammalian immune system, the generation of a T-cell-mediated cytolytic (CTL) response. This enzyme system altered the effect of organophosphorus compounds on the generation of a CTL response. Malathion and fenitrothion were no longer suppressive following this pretreatment; however, ethyl and methyl parathion and fenthion were only partially detoxified. In contrast, the S-9 enzyme system did not alter the effect of carbamate pesticides, carbaryl and carbofuran, on the generation of CTL responses. This report describes the effects of these seven organophosphorus and carbamate pesticides on the generation of the CTL response. In addition, some of the in vivo data published on the immunomodulatory effects of these compounds were collated from the literature and a correlation between in vitro and in vivo studies was discussed.     

Adsorption and degradation of four acidic herbicides in soils from southern Spain

BACKGROUND: Pesticide degradation and adsorption in soils are key processes determining whether pesticide use will have any impact on environmental quality. Pesticide degradation in soil generally results in a reduction in toxicity, but some pesticides have breakdown products that are more toxic than the parent compound. Adsorption to soil particles ensures that herbicide is retained in the place where its biological activity is expressed and also determines potential for transportation away from the site of action. Degradation and adsorption are complex processes, and shortcomings in understanding them still restrict the ability to predict the fate and behaviour of ionisable pesticides. This paper reports the sorption and degradation behaviour of four acidic pesticides in five soils from southern Spain. Results are used to investigate the influence of soil and pesticide properties on adsorption and degradation as well as the potential link between the two processes. RESULTS: Adsorption and degradation of four acidic pesticides were measured in four soils from Spain characterised by small organic matter (OM) contents (0.3-1.0%) and varying clay contents (3-66%). In general, sorption increased in the order dicamba < metsulfuron-methyl < 2,4-D < flupyrsulfuron-methyl-sodium. Both OM and clay content were found to be important in determining adsorption, but relative differences in clay content between soils were much larger than those in OM content, and therefore clay content was the main property determining the extent of herbicide adsorption for these soils. pH was negatively correlated with adsorption for all compounds apart from metsulfuron-methyl. A clear positive correlation was observed for degradation rate with clay and OM content (P < 0.01), and a negative correlation was observed with pH (P < 0.01). The exception was metsulfuron-methyl, for which degradation was found to be significantly correlated only with soil bioactivity (P < 0.05). CONCLUSIONS: Both OM and clay content were found to be important in determining adsorption, but relative differences in clay content between soils were much larger than those in OM content, and therefore clay content was the main property determining the extent of herbicide adsorption for soils of this type. pH was negatively correlated with adsorption for all compounds apart from metsulfuron-methyl. The contrasting behaviour shown for these four acidic pesticides indicates that chemical degradation in soil is more difficult to predict than adsorption. Most of the variables measured were interrelated, and different behaviours were observed even for compounds from the same chemical class and with similar structures.     

Adsorption and partial deactivation of chlorotoluron by burnt straw residues

Adsorption of chlorotoluron by straw ash is related to its carbon content. The ash has a high adsorptive capacity immediately after straw burning but this rapidly declines. The decline is probably due to leaching of an acid organic fraction from the ash. However, the reduced adsorption capacity is still sufficient to account for increases in chlorotoluron adsorption on sites where zero or minimum tillage leaves the ash at or near the surface of the soil.     

稻飞虱寄生性天敌两索线虫田间制约因素的研究

通过异地多点调查和室内测定,分析稻飞虱寄生性天敌两索虫Ａｍｐｈｉｍｅｒｍｉｓｓｐ．成虫的田间基数、垂直分布和活力的制约因子。结果表明：①土壤墒性是两索线虫成虫期的主要影响因素,黑墒条件下,成虫基数高,活力强,垂直分布趋向向０－１０ｃｍ耕作层;②免（少）耕和稻茬后越冬作用种植种类对成虫的影响因地而异;③在土壤ＰＨ５．４５－７．３２范围内,两索线虫成虫适宜生活于黑墒偏酸性土质;④尿素、碳酸铵和硫酸铵对     

稻飞虱寄生性天敌两索线虫田间制约因素的研究

通过异地多点调查和室内测定,分析稻飞虱寄生性天敌两索线虫Amphimermis sp.成虫的田间基数、垂直分布和活力的制约因子。结果表明:①土壤墒情是两索线虫成虫期的主要影响因素。黑墒条件下,成虫基数高、活力强,垂直分布趋向0—10cm耕作层;②免(少)耕和稻茬后越冬作物种植种类对成虫的影响因地而异;③在土壤pH5.45—7.32范围内,两索线虫成虫适宜生活于黑墒偏酸性土质;④尿素、碳酸铵和硫酸铵对成虫有很强的刺激性和不同程度的致死作用,碳酸铵作用最强;⑤三唑酮等11种药剂对成虫无可见影响,杀虫双等其它10种化学农药则有不同程度的刺激性和致死作用;⑥比较测定杀虫双等9种农药对两索线虫成虫的LC_(50)。     

毒死蜱和氰戊菊酯在土壤中的吸附与迁移

为评估被用作白蚁预防药剂的毒死蜱和氰戊菊酯在土壤中的移动性,采用平衡吸附法和薄层层析法分别测定了两种农药在浙江宁波地区的东钱湖土(粉砂质壤土)、青岭土(粉砂质壤土)和象山土(粉砂质黏壤土)3种土壤中的吸附常数(Kd)和迁移率(Rf)。结果表明,两种供试药剂在东钱湖土中的吸附等温线线性化程度均较高,而在青岭土和象山土中的吸附等温线均近似于 "L"型。从Kd和有机质吸附常数Koc的数值看,氰戊菊酯在土壤中的吸附作用主要受土壤有机质因素影响,而毒死蜱的吸附并非只受土壤有机质因素的影响。毒死蜱在3种供试土壤中的Kd和Rf值均高于氰戊菊酯。这表明由Kd值推测不同农药在土壤中的相对移动性可能会存在一定偏差。毒死蜱和氰戊菊酯在3种土壤中的Rf值由大到小的顺序为:东钱湖土>青岭土>象山土;而Kd值由大到小顺序为象山土>青岭土>东钱湖土。对Kd和Rf值与土壤理化性质的多元线性回归分析表明:1)土壤有机质含量和阳离子代换量在决定Kd和Rf值中所起的作用相互重叠;2)土壤有机质含量(或土壤阳离子代换量)和土壤黏粒含量是影响Kd和Rf值的关键因素,而土壤pH值对于Kd和Rf值无决定性影响。