霸螨灵在棉花和土壤中的残留降解动态

于2006和2007年在济南和杭州2地进行田间试验,采用液液萃取和高效液相色谱检测方法,研究了霸螨灵在棉叶、棉籽和土壤中的残留降解动态.试验结果表明:本方法中霸螨灵的最低检出浓度为0.01 mg·kg-1(以S/N=3计),霸螨灵添加浓度为0.10、0.50、1.00 mg·kg-1时,其在棉叶、棉籽和土壤中的添加回收率为72.5%～103.1%;霸螨灵在济南和杭州2地的消解趋势基本一致,在棉叶中的半衰期为3.8～4.3 d,在土壤中的半衰期为8.8～9.6 d;霸螨灵在棉籽中的最终残留量均<0.01mg·kg-1,在土壤中的最终残留量<0.01～0.98 mg·kg-1.建议我国将霸螨灵在棉籽中的MRL(最高残留限量)值定为0.1 mg·kg-1.     

表面活性剂和金属离子对新农药硫肟醚光解的影响

硫肟醚[O-(3-苯氧苄基)-2-甲硫基-1-(4-氯苯基)丙基酮肟醚]是我国研制成功的具有自主知识产权的一种新型杀虫剂.在室内紫外光(λ254 nm)照射下研究了几种表面活性剂和金属离子对硫肟醚在水溶液中光解的影响.试验结果表明,当土温80(Tween80)、十二烷基苯磺酸钙(ABS-Ca)、蓖麻油聚氧乙烯醚(BY)、三氯化铁(FeCl_3)、硫酸铜(CuSO_4)和无水硫酸镁(MgSO_4)分别与硫肟醚以1:1的比例混合后,硫肟醚的光解速率发生了不同程度的改变.ABS-Ca对硫肟醚在水溶液中的光解速率表现出显著的光猝灭降解效应,蓖麻油聚氧乙烯醚类表面活性剂BY对硫肟醚在水溶液中的降解表现出一定程度的光敏化作用.而吐温80对硫肟醚在水体中光解速率的影响则随照光时间而改变,当照光时间小于40 min时,表现为光敏化降解作用,大于40 min时可延缓硫肟醚的光解进程,表现出光猝灭作用.Fe~(3+)使硫肟醚在水溶液中的光解速率增快,表现出明显的光敏化降解效应,而Cu~(2+)和Mg~(2+)使硫肟醚在水体中的光解速率减慢,表现为较强的光猝灭降解作用.硫肟醚在含Tween80、ABS-Ca、BY、FeCl_3、CuSO_4和MgSO_4水溶液中的光解半衰期分别为21.63、34.42、15.29、9.85、43.95和32.20 min,而在不含任何农药化肥的纯净水中的光解半衰期为22.30 min.     

乙烯菌核利在水溶液中的光解动力学

以高压汞灯和太阳光为光源,研究乙烯菌核利在重蒸水、自来水、湖水及pH缓冲液中的光解动力学。高压汞灯下,乙烯菌核利在重蒸水中的光解半衰期约为28 m in,而在太阳光下为3.86 h。自来水和湖水中溶解性物质对乙烯菌核利在高压汞灯下的光解动力学仅有微弱的淬灭效应,但在太阳光下表现出显著的敏化效应,照光3 h的敏化效率分别为138%和126%。2种光源下,pH 5.0和pH 7.0缓冲液对乙烯菌核利的光解均表现为光淬灭效应,高压汞灯照光60 m in的淬灭效率分别为69%和57%,太阳光照光7 h的淬灭效率分别为77%和33%;pH 9.0缓冲液则表现出显著的敏化效应,高压汞灯照光20 m in的敏化效率为58%,而太阳光照光1 h的敏化效率则达到了415%。     

乙烯菌核利在水溶液中的光解动力学

以高压汞灯和太阳光为光源，研究乙烯菌核利在重蒸水、自来水、湖水及pH缓冲液中的光解动力学。高压汞灯下，乙烯菌核利在重蒸水中的光解半衰期约为28min，而在太阳光下为3．86h。自来水和湖水中溶解性物质对乙烯菌核利在高压汞灯下的光解动力学仅有微弱的淬灭效应，但在太阳光下表现出显著的敏化效应，照光3h的敏化效率分别为138％和126％。2种光源下，pH5．0和pH7．0缓冲液对乙烯菌核利的光解均表现为光淬灭效应，高压汞灯照光60min的淬灭效率分别为69％和57％，太阳光照光7h的淬灭效率分别为77％和33％；pH9．0缓冲液则表现出显著的敏化效应，高压汞灯照光20min的敏化效率为58％，而太阳光照光1h的敏化效率则达到了415％。     

甲基对硫磷对三种拟除虫菊酯杀虫剂的光敏降解研究

本文以高压汞灯和自然阳光为光源，研究了甲基对硫磷对氧氰菊酯、溴氰菊酯和氰茂菊酯在玻片表面光致降解的影响。结果表明：甲基对硫磷与三种拟除虫菊酯农药混合照光处理后，可使拟除虫菊酯农药的光解速度加快。氯氰菊酯、氰戊菊酯和溴氰菊酯的光解半衰期，在高压汞灯下比其单独照光分别缩短１２．１８、８．４６和７．３３倍，在阳光下则分别缩短４．７３，２．６５，和４．４６倍。甲基对硫磷对三种拟除虫菊酯农药表现出显著的光敏     

农药阿维菌素在水中的光解动态及机理

为了科学评价农药阿维菌素的环境安全性,采用室内模拟方法研究了其在水环境中的光解动态,考察了波长、光强和添加物质等对阿维菌素光降解的影响,进而利用LC/MS鉴定了其主要降解产物,并对降解机理进行了初步探讨.结果表明:紫外灯辐射波长对阿维菌素的光解速率影响较大,波长越短,越有利于阿维菌素的光降解;模拟太阳光强度越大,阿维菌素的光解速率越快;1%H_2O_2、0.1%TiO_2和10%丙酮作为添加物质都能加快阿维菌素的光解进程;通过分析阿维菌素光解产物的TIC图和质谱图,可能主要有两种代谢产物,分析了其降解途径及机理.     

三唑酮在水中的光化学降解及其影响因素

以太阳光和高压汞灯为光源,研究了水溶液中三唑酮光化学降解的影响因子。结果表明:在不同光源和透光介质下,三唑酮的降解能力从大到小依次为:石英试管 高压汞灯、玻璃试管 高压汞灯、石英试管 太阳光、玻璃试管 太阳光、暗室;水溶液中三唑酮初始浓度越高,其光降解率越低,呈负相关关系;丙酮对三唑酮在水中的光解有极显著的光敏作用,光敏效率与丙酮添加量有显著相关性;三唑酮的光解实质为光氧化作用,溶解氧含量对三唑酮光解有重大影响。     

南京东郊蔬菜种植基地地表水氮、磷、重金属含量及影响因素

南京东郊典型蔬菜基地地表水环境质量的调查分析表明:(1)在当前的生产和生活条件下,地表水尚未受Pb、Cu、Zn、Cd和Cr污染,但有不同程度的氮、磷污染。(2)河流氮、磷污染比池塘严重。河流水中氨氮和水溶性磷的比例相对较高,而池塘水中硝态氮、有机氮和有机磷的比例相对较高,这种差别有助于识别地表水中氮、磷的来源。河流底泥中总氮、总磷和重金属含量(Cr除外)比塘泥高,表明河水氮、磷及重金属污染风险比池塘水高。(3)南京东郊蔬菜基地地表水中氮、磷及重金属主要来自城市生活污水的排放,其次来自蔬菜栽培中有机肥过量投入造成的流失。因此,保护城郊地表水应从城市生活污水净化和蔬菜栽培中有机肥的合理施用入手。     

Residues,half-life times,dissipation, and safety evaluation of the acaricide fenpyroximate applied on grapes

A validated high-performance liquid chromatography–diode array detector method for simultaneous determination of the acaricide fenpyroximate on grape was developed. Estimated limit of detection and limit of quantification for fenpyroximate were 0.01 and 0.05 mg kg^?1, respectively. The intra- and inter-day precisions performed with relative standard deviation were better than 9.3% and 8%, respectively, while recoveries were in the range of 88.5%–100.4%. Residue levels of fenpyroximate in grape samples collected 10 days after field application were below the established maximum residue level values. The dissipation rates of fenpyroximate were described using first-order kinetics and its half-life, were approximately 3.5 days in grape. This study provides basic information for developing regulations to safeguard the use of fenpyroximate in grapes and prevent any potential health concerns for consumers.     

Improvement of the photostability of selected substances in aqueous medium

The photodegradation of some pesticides in water has been investigated. The kinetics of the photochemical processes is discussed and the photolytic half‐life is calculated. The objective of this paper is to present some of the recent results on the kinetics and on the products of sunlight‐induced reactions of Parathion, Gardona, Diazinon, Atrazine and Phenmediphame at low concentrations in distilled water and fresh water. The quantum yield, measured at 263 nm for Phenmediphame in aerated water at 5 × 10^‐4 M and 30°C, was 1.4 × 10^‐2, and for Parathion, measured at 300 nm in aqueous solution at 3.42 M at pH 6.4 and 25 °C, was 1.5 × 10^‐3. The measured absorption spectra and the variable light intensity were used to estimate the environental phototransformation process and the persistence of these compounds in water.     

High performance liquid chromatographic determination of pesticides in soluble phase and suspended phase in river water

A high performance liquid chromatographic method has been developed to determine pesticides in river water as both dissolved phase and suspended phase. The target pesticides were eight herbicides, asulam, diuron, flazasulfuron, linuron, MCPB, mecoprop, pyrazosulfuron‐ethyl and siduron, and two fungicides, oxine‐copper and thiram. The pesticides in filtered river water were extracted with styrene‐divinylbenzene copolymer and were eluted with acetonitrile. The pesticides on suspended solids were extracted ultrasonically with acetonitrile. Each eluate was concentrated and analyzed by HPLC with multiwavelength detector. Recoveries of the pesticides in the overall procedure of this method were 78–114% for filtered river water and 75–107% for suspended solids. The limits of detection in water and suspended solids ranged from 0.1 to 0.9 μg/L and 1 to 7 μg/g, respectively. Pesticide distribution between soluble phase and suspended phase in river water was measured by this method.     

铁(III)-丙酮酸盐配合物光解引发水中铬(Ⅵ)还原

初步研究了含有Fe(III)及丙酮酸盐的溶液在高压汞灯照射下对铬(VI)的光还原反应.考察了溶液pH值、Fe(III)浓度、丙酮酸钠浓度、Cr(VI)浓度对反应的影响.分析了光还原反应的动力学及反应机制.结果表明:铁丙酮酸盐体系能光还原Cr(VI);最佳pH为3.0;Cr(VI)光还原的初始速率随着加入的铁(III)、丙酮酸盐、Cr(VI)初始浓度的增加而增加;实验条件下的表观动力学方程为:-dCCr(VI)/dt=0.021[Cr(VI)]0.39[Fe(III)]1.05[CH3COCOONa]0.39;Fe(III)-丙酮酸盐配合物光解产生的Fe(II)是Cr(VI)的主要还原剂.