有机氮农药多残留分析方法的研究

提出了用气相色谱直接测定水、土、粮食水果和蔬菜中10种有机氮农药多残留的分析方法.样品采用丙酮振荡或组织捣碎提取,二氯甲烷萃取,经凝结或柱层析法净化.使用Sigma2型带NPD的气谱仪测定.气谱柱长1m,内径0.2cm,填充5％OV-17/Gas Chrom Q(80—100目),该柱在恒温的色谱条件下能将10种有机氮农药完全分离.通过方法回收率及八种类型样品的添加回收率证实方法的可靠及可行性,共添加回收率为81.76—102.03％,变异系数0.52—10.33％,最低检测浓度为0.0004—0.0218ppm.     

有机磷农药的多残留气相色谱分析方法

本文提供了一个简单、快速测定16种有机磷农药的多残留分析方法,样品经丙酮、水混合溶剂提取,加入氯化钠析出丙酮,再加二氯甲烷提取水相中残留的少量有机磷农药,分出有机相,经无水硫酸钠干燥后浓缩,用气相色谱仪测定。经饮用水、土壤、果蔬、谷物、烟草等添加试验,回收率为75.00—105.26％;变异系数为0.61—16.49％;最低检出浓度为1.2×10~(-3)mg/kg。     

粤桂琼区域水源地有机磷农药的生态风险评价

利用气相色谱-质谱检测粤桂琼(广东、广西、海南三省区)区域水源地9个采样点水样中的有机磷农药浓度,构建了淡水生物对有机磷农药的物种敏感性分布,并计算出各类水生生物的HC₅(hazardous concentration for 5% the species)值;采用基于浓度加和模型的混合物风险商值法和商值概率分布法,评价了粤桂琼区域水源地中敌敌畏、内吸磷、阿特拉津、甲基对硫磷、乐果、马拉硫磷和对硫磷7种有机磷农药的的生态风险,同时利用聚类分析法对9个采样点进行了生态风险评价. 结果表明:粤桂琼区域水源地7种有机磷农药的总质量浓度在nd~1 260.95 ng/L之间,平均值为184.68 ng/L,主要以马拉硫磷、甲基对硫磷、对硫磷和乐果为主. 东莞东江南支流、玉林苏烟水库和柳州柳江水源地的生态风险级别相对较高. 敌敌畏、对硫磷、甲基对硫磷的HC₅值均低于0.1 μg/L,这3种物质对生态系统毒性效应较大. 根据风险商结果排序可知,粤桂琼区域水源地预防的重点为甲基对硫磷、对硫磷和马拉硫磷对水生生物的危害,其中甲基对硫磷是对混合风险商贡献最高的污染物,其危害指数达21.313;在95%的置信区间内,甲基对硫磷、对硫磷和马拉硫磷的生态风险较大,风险商超过1的概率为5%,应作为最优先控制的污染物.      

气相色谱/原子发射检测器(GC/AED)在环境化学分析中的应用

概述了GC/AED的原理、特点及其在环境化学分析中的应用,例如,分析地表水中1 μg/L水平的有机氯、有机磷、有机氮和有机硫化物农药。AED可检测C、S、P、Cl、N等25种元素。通常需要几种不相同的常用的选择性检测器才能检测上述农药中不同的原子,这些检测器包括电子捕获检测器、氮磷检测器、火焰光度检测器和霍尔电导检测器。      

阿维菌素在稻田水、土壤及稻米中的残留研究

采用田间试验方法,应用HPLC法测定了阿维菌素在水稻水、土壤及稻米中的残留。结果表明：阿维菌素在稻田水、土壤及稻米中的平均添加回收率分别在85.51%～87.98%、78.57%～83.09%、82.74%～86.80%之间。阿维菌素的最小检出量为4.824×10^-10g,水、土壤、稻米中阿维菌素的最低检测浓度分别为0.001 mg/kg、0.014 mg/kg、0.01 mg/kg。该药属易分解农药（T1/2〈30 d）,按推荐使用剂量使用时收获的稻米是安全的。     

珠江河口水域有机磷农药水生生态系统风险评价

通过风险商法和概率风险法评价了珠江河口水域中甲拌磷、敌敌畏及乙拌磷等9种有机磷农药对硅藻、水蚤及糠虾等8种水生生物的生态风险.风险商法评价结果表明,9种有机磷农药混合物总风险商为:糠虾处于高风险中水平,水蚤和摇蚊在中等风险水平,硅藻、牡蛎、鲤鱼、鲶鱼和鳗鱼均处于低风险水平;甲拌磷对风险值的贡献最大,且对每种生物都有影响.概率风险法结果表明,以HC5为参考值评估总风险商时,95%置信水平下的HC5比50%置信水平的HC5保守,50%置信水平的HC5中乐果的HC5最大,毒死蜱的最小;丰水期9种有机磷农药混合物总风险比枯水期农药混合物总风险大,甲拌磷对总风险贡献最大.单一污染物的概率风险表明,甲拌磷和乙拌磷对珠江河口水域中10%以上的生物都有危害;而9种有机磷农药混合物的概率风险表现为:丰水期大于枯水期,均大于5%,说明超过了保护95%生物的安全阈值.     

Separation of chlorinated hydrocarbons and organophosphorus, pyrethroid pesticides by silicagel fractionation chromatography and their simultaneous determination by GC-MS

A silicagel fractionation procedure for environmental sample extracts, which separates chlorinated hydrocarbons(CHCs) and organophosphorus, pyrethroid pesticides into two groups for subsequent instrumental analysis, was developed in this study. This method was achieved by optimizing the fraction cut-off volume of elution and different solvents. Using fully activated silica gel and cut-off CHCs collection after 10ml 10% dichloromethane (DCM) in n-hexane passing through the column resulted in satisfactory separation of CHCs and organophosphorus, pyrethroid pesticides. This procedure had a higher reliability for CHCs than for organophosphorus, pyrethroid pesticides, because there is a relatively reliable recovery for CHCs. This approach is less expensive due to reducing sample pre-treatment time and solvent consumption.     

涕灭威在烟草及土壤中残留动态研究

烟草,土壤中涕灭威总有毒残留分别用丙酮、丙酮与水混合液提取,过氧乙酸氧化,液-液分配和柱层析净化后,气相色谱检测。方法回收率在83~105%之间,土壤、鲜烟叶和干烟叶中的最小检出浓度分别为0.0135ppm,0.0169ppm和0.0339ppm。      

超声波萃取-毛细管气相色谱法测定土壤和底质中的25种有机氯农药研究

建立了超声波萃取、Florisil柱净化,SPB-5毛细管柱分离,ECD检测器测定土壤和底质中25种有机氯农药的方法.该方法的检出限为0.079 μg/kg ～1.2 μg/kg,加标回收率为73.1％ ～ 126.5％,相对标准偏差为3.3％ ～9.7％.实验结果证明,该方法灵敏度高、精密度高,操作快速简便,满足土壤和底质中有机氯农药的测定要求.     

Effect of copper on the degradation of pesticides cypermethrin and cyhalothrin

The influence of coexisting copper (Cu) ion on the degradation of pesticides pyrethroid cypermethrin and cyhalothrin in soil and photodegradation in water system were studied.Serial concentrations of the pesticides with the addition of copper ion were spiked in the soil and incubated for a regular period of time,the analysis of the extracts from the soil was carried out using gas chromatography (GC).The photodegradation of pyrethroids in water system was conducted under UV irradiation.The effect of Cu~(2 ) on the pesticides degradation was measured with half life (t_(0.5)) of degradation.It was found that a negative correlation between the degradation of the pyrethroid pesticides in soil and Cu addition was observed.But Cu~(2 ) could accelerate photodegradation of the pyrethroids in water.The t_(0.5) for cyhalothrin extended from 6.7 to 6.8 d while for cypermethrin extended from 8.1 to 10.9 d with the presence of copper ion in soil.As for photodegradation,t_(0.5) for cyhalothrin reduced from 173.3 to 115.5 rain and for cypermethrin from 115.5 to 99.0 min.The results suggested that copper influenced the degradation of the pesticides in soil by affecting the activity of microorganisms.However, it had catalyst tendency for photodegradation in water system.The difference for the degradation efficiency of pyrethroid isomers in soil was also observed.Copper could obviously accelerate the degradation of some special isomers.     

Temporal trends in organophosphorus pesticides use and concentrations in river water in Japan, and risk assessment

We reviewed organophosphorus pesticide use in Japan between 1982 and 2016 using data from the National Institute of Environmental Studies. Organophosphorus pesticide concentrations in river water throughout Japan were taken from the literature, and risk assessments were performed for some organophosphorus pesticides based on risk quotients and hazard quotients. Assessments were performed for 20 common pesticides, including insecticides, fungicides, and herbicides. The amounts used decreased in the order: insecticides?>?herbicides?>?fungicides. Organophosphorus insecticide and fungicide use have decreased over the last four decades, but organophosphorus herbicide use has increased. During this period, annual organophosphorus pesticide use was the highest for chlorpyrifos (105,263?tons/year) and the lowest for glyphosate-sodium (8?tons/year). The ecotoxicological risk assessment indicated that diazinon and fenitrothion posed strong risks to the Japanese aquatic environment, and chlorpyrifos and malathion have moderate risks. None of the pesticides that were assessed posed significant risks to humans. Continued use of organophosphorus pesticides in Japan may cause strong risks to aquatic environments. These risks should be reassessed periodically.     

通用浓度加和模型预测有机磷与三嗪农药对绿藻的联合毒性

基于微板藻毒性试验测定5个有机磷农药与4个三嗪类农药的单个及联合毒性.根据半数效应浓度(EC50),对斜生栅藻96h生长抑制的毒性大小顺序为:西草净>阿特拉津>扑灭通>苯嗪草酮>草甘膦>敌敌畏>磷胺>乙酰甲胺磷>甲胺磷.这表明直接干扰光合作用电子传输的三嗪除草剂的藻毒性明显大于有机磷农药.以通用浓度加和作为参考模型,三嗪类农药按EC50和EC10(10%效应浓度)浓度比的混合物对斜生栅藻呈现加和毒性.有机磷农药按EC50和EC10浓度比的混合物在低浓度呈现加和毒性,在高浓度呈现协同毒性.有机磷与三嗪类农药按EC50和EC10浓度比的混合物在低浓度为加和毒性,在高浓度为协同毒性.     

Analysis of organophosphorus pesticides in water samples using a continuous membrane permeation extractor

A membrane permeation method used for the determination of organophosphorus pesticides (OPPs) at trace levels in water is described. OPPs were collected on Tenax-TA polymeric resin after permeating through a silicone polycarbonate membrane. OPPs were then stripped by thermal desorption and directed into a gas chromatograph using a helium stream for quantitative analysis. A linear relationship was found between the mass collected on Tenax-TA and the product of external concentration and exposure time. The method detection limits (MDL) for OPPs were 0.26–2.37 μg/l with the relative standard deviations (R.S.D.) less than 20%. This method provides an easy, low-cost way of preconcentrating samples. It eliminates the involvement of any organic solvent, and has the potential for automated on-site analysis of OPPs in water.     

A complete set of procedure for determination of multiresidue of pesticides in vegetables

A complete set of procedure for determination of multiresidue of pesticides in vegetables was presented in this paper.The complete set of procedure included three steps:bioassay,cholinesterase inhibition and GLC analysis.The samples could be identified to be contaminated with pesticides if 5% of house flies was knocked down in 50 tested house flies. Those samples contaminated with pesticides needed to be detected by AChE inhibition method.The qualitative and quantitative analyses were carried out by GLC.Recoveries ranged from 83.7% in Chinese cabbages to 105.6% in tomatoes for pyrethroids,and 84.0% in tomatoes to 102.7% in sweetbell redpeppes for organophosphorus compounds.Coefficients of variations ranged from 0.59% to organophosphorus compounds.Coefficients of variations ranged from 0.59% to 7.87% for pyrethroids. and 0.33% to 9.88% for organophosphorus compounds with vegetables. The complete set of procedure has been used successfully to analyze 7000 samples collected in Beijing. About 1% of the samp     

湘江流域土壤中有机氯农药的残留规律

2004年5月采集了湘江流域51个样品,用AES萃取技术,使用GC-MS方法测定了样品中的六氯苯(HCB)、滴滴涕(DDTs)、氯丹、艾氏剂、狄氏剂、异狄氏剂、七氯和灭蚁灵等有机氯农药(OCPs). 结果表明:HCB和DDTs的检出率为100%,氯丹和灭蚁灵的检出率较低,艾氏剂、狄氏剂、异狄氏剂和七氯未检出,说明HCB和DDTs曾在湘江流域广泛施用. w(OCPs)平均值为145.49 μg/kg,其中w(DDTs)占w(OCPs)的90.9%,且有些土壤样品中w(DDT)/w(DDE+DDD)较大,说明DDTs曾作为湘江流域的主要杀虫剂施用过,并且近期仍然有输入. 农药残留量与农药的施用量成正比,农药施用量高的衡阳地区,其土壤中的农药残留量最高. 不同使用功能的土壤中有机氯农药的残留量不同,表现为旱地中的残留量高于水稻地,蔬菜地中以辣椒地的残留量最高.      

土壤中毒虫畏和倍硫磷复合污染物的降解规律

采用土壤室内培养,气相色谱仪测定的方法,研究了毒虫畏和倍硫磷2种有机磷杀虫剂的复合污染物在红壤中的降解规律.结果表明:在复合污染下,倍硫磷的降解显著快于其在单一污染下的降解;土壤水分饱和条件下,倍硫磷的降解与对照差异不大,而毒虫畏的降解量在加入农药后的前21d比对照高33.3%～1 250%;在土壤干旱条件下,倍硫磷的降解量比对照略有降低,而毒虫畏的降解量在前期则比对照显著增加;施用氮肥能促进复合污染物的降解;在去除有机质的红壤矿物中,倍硫磷的化学降解量比对照降低22.4%～30.8%,而在加入农药后的前21d,毒虫畏的化学降解量比对照增加42.1%～2 370%,随后又下降.因此,复合与单一农药的污染物在土壤中的降解规律是不同的,复合污染的有机磷农药在土壤中的降解是相互影响的.     

南京市小河流表层沉积物中的有机氯农药残留及其分布现状

004年春,以南京市西南部4条通入长江的小河流为试区,采集不同断面表层沉积物和水样,以及相应流域内农田土壤样品,对所有样品中有机氯农药的残留及其分布状况进行研究,并讨论了农田土壤有机氯农药残留量和理化性质对河流表层沉积物中有机氯残留量的影响.结果表明:沉积物对水体HCHs和DDTs有明显的富集作用,不同河流富集状况不尽相同.农田土壤中HCHs与沉积物中HCHs残留量基本相近,土壤中DDTs残留量明显高于沉积物,可见土壤中HCHs更易迁移至水系.由于土壤有机质易于从偏碱性的土壤中淋出,吸附在有机质上的有机氯残留物易随之转移至沉积物中,因此在流经偏碱性土壤的河流沉积物中OCPs残留量较高.各流域内农田土壤与河水及沉积物中α/γ及DDE/DDT值的变化有一定程度的趋同性,反映了土壤是水体及沉积物中OCPs的主要来源.此外,有机氯各组分在土壤-水体-沉积物的迁移过程中,易迁移者在沉积物中含有较高比例.此外,沉降作用将大大降低小河流向长江输入的OCPs.     

4种农药在稻田水中的残留降解

对乐果、杀虫单、丁草胺和氰戊菊酯４种 经，在稻田水中的残留降解情况，进行了及比较。结果表明，４种农药在稻田水中的残留降解符合Ｃ－Ｃｏ．３＾ｋｔ或Ｃ＝Ａ．ｅ＾－１６＋Ｂ．３＾βｉ的数学式，据此可计算其平均降解半衰期（ｔ０．５）分别为：１．８６、１．３５、０．８８和０．３８ｄ，其中丁草胺和氰戊菊酯的降解前快后慢，氰戊菊酯的降解愉丁乐果，土壤吸附氰戊菊酯是其降解快的重要原因，脂溶性农药对水环境的污染要轻     

灭多威在水稻上的残留检测及降解动态研究

利用气相色谱-火焰光度法(GC-FPD)研究了灭多威在水稻田田水、土壤、水稻植株和水稻糙米中的残留及降解动态. 当灭多威的添加量为0.045～0.450 mg/kg时,其在水稻糙米、植株、土壤和田水中的平均回收率分别为82.8%～91.0%,84.4%～98.1%,83.7%～90.3%和85.9%～86.9%,变异系数分别为5.2%～8.1%,6.8%～9.0%,3.7%～7.7%和6.4%～8.3%. 测定了灭多威在湖南长沙、湖北罗田、江西樟树和浙江杭州4个水稻主产区的水稻植株、土壤及田水中的降解动态. 结果表明,灭多威在湖南长沙、湖北罗田、江西樟树和浙江杭州的水稻植株上的降解半衰期分别为16.08,4.47,15.93和22.87 h,在湖南长沙、湖北罗田和江西樟树水稻田田水中的降解半衰期分别为6.74,3.88和28.06 h. 灭多威在浙江杭州水稻田田水中未被检出,其在4个研究区稻田土壤中也未被检出. 按照推荐剂量的倍量施药,在施药14 d后,灭多威在水稻糙米中的残留量均低于日本肯定列表制度规定的在稻米上的最大残留允许量(0.5 mg/kg).      

应用标准方法测定农药对蚯蚓的毒性

本文论述使用标准化的人工土壤测定农药对蚯蚓的急性毒性的方法.实验结果证明,适用于测定农药对蚯蚓毒性的人工土壤组成为:石英砂830g/kg(干重,下同)、草炭100g/kg、膨润土50g/kg、碳酸钙10g/kg、马粪10g/kg.利用人工土壤测定久效磷、多菌灵、呋喃丹、林丹及甲基对硫磷对蚯蚓(Eiseniafoetida)的毒性.其半数致死浓度(LC_(50))分别是:0.18、4.27、12.9、70.85、74.52ppm.经用三种不同类型的自然土壤(东北黑土、华北褐土、江西红壤)及人工土壤测定呋喃丹对蚯蚓的毒性后,证实呋喃丹在人工土壤中对蚯蚓的半数致死浓度(12.9ppm)处于三种自然土壤的LC_(50)值(褐土6.9ppm、红壤12.7ppm、黑土19.2ppm)之间,表明人工土壤具有一定的代表性,用人工土壤进行农药对蚯蚓的毒性研究是可行的.