间接竞争ELISA法测定稻田土壤中除草剂毒莠定的残留量

通过对反应体系中酶标二抗(辣根过氧化物酶标记羊抗兔IgG)和抗体的最佳稀释浓度等条件的筛选和确定,最终建立了一种快速灵敏地测定污染稻田土壤中毒莠定残留量的方法--间接竞争ELISA分析方法.结果表明,酶标二抗和抗体的最佳稀释度均为1:500(体积比),毒莠定的检出下限达到5 ng·mL-1,在0.07～0.7μg·mL-1浓度范围内有良好的线性;土壤浸出液加样的平均回收率为104.11%,变异系数在3.13%～11.13%之间,符合农药残留分析的要求;样品基质对检测结果没有干扰.     

高铁酸钾对菠菜中3种有机磷农药残留降解的影响

菠菜(Spinaciao leracea L.)是我国出口的重要蔬菜品种之一,其农药残留是制约我国菠菜出口的重要"技术壁垒".在露地栽培条件下,研究了叶面喷施高铁酸钾水溶液对菠菜中有机磷农药的降解作用,并探讨了高铁酸钾对菠菜相关酶活、MDA含量及品质指标的影响.结果表明,叶面喷施不同浓度的高铁酸钾(200、400、600mg·L-1)可有效降低菠菜中敌敌畏、毒死蜱和乐果等有机磷农药的残留量.随着高铁酸钾喷施浓度的增大,菠菜中敌敌畏、毒死蜱和乐果残留量显著降低;试验浓度下以600mg·L-1高铁酸钾处理的降解效果最好,可使菠菜中敌敌畏、毒死蜱和乐果的降解率达到72.43%、87.15%和75.45%.叶面喷施高铁酸钾对菠菜过氧化物酶(POD)、过氧化氢酶(CAT)活性、MDA含量以及品质指标没有明显影响.试验表明高铁酸钾具有降解有机磷农药残留的作用,在菠菜生产中将高铁酸钾作为有机磷农药残留降解制剂是可行的.     

一级动力学反应方程参数估计中若干问题的讨论

在农药的环境行为研究中,常用一级动力学反应方程来模拟农药的降解或残留。本文论述了用线性回归分析法估计一级化学动力学方程参数时存在的初始浓度飘移和非本义最优化问题,讨论了与此相关联的试验设置、安全间隔期、分段模拟和试验数据处理等问题,提出了解决问题的初步设想。     

拟除虫菊酯类农药废水处理技术研究进展

拟除虫菊酯类农药废水COD浓度高、毒性大、污染物成分复杂、较难生物降解。通过系统阐述目前国内外各种针对拟除虫菊酯类农药废水处理技术的最新研究动态,分析了各种方法的优缺点,并对此类农药废水处理技术的发展方向进行了展望,可为此类废水处理工艺选择和工程设计提供有益参考。     

地形和季节变化对有机氯农药分布特征的影响——以四川省成都经济区为例

在成都经济区典型地貌单元（平原区和丘陵区）采集春季和秋季样品,共计52件农作物样品和100件土壤样品,通过美国EPA8080A方法测试样品中有机氯农药含量,以研究不同地貌单元不同季节有机氯农药污染分布特征。结果表明：土壤中DDT含量高于HCH含量;平原区绵竹市土壤中有机氯农药含量高于丘陵区盐亭县土壤有机氯农药含量;在平原区的绵竹市,秋季采集的土壤中有机氯农药含量高于春季样品中有机氯农药含量;在丘陵区的盐亭县,春季采集的土壤有机氯农药含量高于秋季样品中含量。农作物中有机氯农药的检出率较高,各种作物浓度均未超标,但对人们健康具有潜在危害。油脂含量高的粮食作物中有机氯农药含量高于叶类蔬菜和果实类蔬菜中有机氯农药的含量。地貌类型、土壤有机质含量以及有机氯农药施用是造成两个地区春、秋季土壤含量特征不同的主要原因,而植物的吸收方式、OCP的物理化学性质是影响农作物中OCP含量不同的主要因素.     

大连市化肥农药流失影响模拟研究

以海域生态环境保护为目的,开创性地引用高等数学中的拉格朗日中值定理,结合水土流失通用方程,从土壤有机质含量、地面植被覆盖类型、植被覆盖率和流失距离等方面,模拟计算其对化肥农药流失产生的影响力,得出不同条件下控制化肥农药流失的理论经济点和敏感点,提出综合分析结论,为城市决策、规划和管理等提供科学依据.     

Beyond a bottle of liquid: pesticide dependence in transitional rural China

Pesticide dependence is a major threat to food safety and local environment. Although numerous studies have explored different causes of pesticide dependence, few have examined how pesticides are locked into agricultural modernisation and rural transformation. Based on a case study of a Chinese village, this paper demonstrates how agricultural modernisation trajectory and rural changes have perpetuated the use of pesticides as necessities in agriculture as well as for farmers' livelihoods. Modern technologies, such as hybrid rice, conservation tillage, changes in crop structure, and reduction of intercropping all contribute highly towards pesticide dependence. The household responsibility system in China has provided the institutional foundation for increased pesticide use. Rural transformations driven by livelihoods diversification have created conducive social spaces for pesticide application. To step out of pesticide dependence, promotion of genetic diversity in agriculture, a reassessment of locational suitability of conservation tillage, institutional strengthening and the promotion of integrated pest management methods are suggested.     

Rapid determination of residues of pesticides in honey by µGC-ECD and GC-MS/MS: Method validation and estimation of measurement uncertainty according to document No. SANCO/12571/2013

A simple and straightforward method for simultaneous determination of residues of 13 pesticides in honey samples (acrinathrin, bifenthrin, bromopropylate, cyhalothrin-lambda, cypermethrin, chlorfenvinphos, chlorpyrifos, coumaphos, deltamethrin, fluvalinate-tau, malathion, permethrin and tetradifon) from different pesticide classes has been developed and validated. The analytical method provides dissolution of honey in water and an extraction of pesticide residues by n-Hexane followed by clean-up on a Florisil SPE column. The extract was evaporated and taken up by a solution of an injection internal standard (I-IS), ethion, and finally analyzed by capillary gas chromatography with electron capture detection (GC-µECD). Identification for qualitative purpose was conducted by gas chromatography with triple quadrupole mass spectrometer (GC-MS/MS). A matrix-matched calibration curve was performed for quantitative purposes by plotting the area ratio (analyte/I-IS) against concentration using a GC-µECD instrument. According to document No. SANCO/12571/2013, the method was validated by testing the following parameters: linearity, matrix effect, specificity, precision, trueness (bias) and measurement uncertainty. The analytical process was validated analyzing blank honey samples spiked at levels equal to and greater than 0.010 mg/kg (limit of quantification). All parameters were satisfactorily compared with the values established by document No. SANCO/12571/2013. The analytical performance was verified by participating in eight multi-residue proficiency tests organized by BIPEA, obtaining satisfactory z-scores in all 70 determinations. Measurement uncertainty was estimated according to the top-down approaches described in Appendix C of the SANCO document using the within-laboratory reproducibility relative standard deviation combined with laboratory bias using the proficiency test data.     

Simultaneous gas chromatographic determination of chlorpyrifos and its impurity sulfotep in liquid pesticide formulations

An analytical method for simultaneous determination of the active substance (chlorpyrifos) and its relevant impurity (sulfotep) in commercial pesticide formulations has been developed and validated. The proposed method entails extraction of the analytes from samples by sonication with acetone and analysis by gas chromatography-flame ionization detection (GC-FID). The proposed method was characterized by satisfactory accuracy and precision. The repeatability expressed as relative standard deviation (RSD) was lower than the acceptable values calculated from the modified Horwitz equation whereas individual recoveries were in the range of 98–102% and 80–120% for chlorpyrifos and sulfotep, respectively. The limit of quantification (LOQ) for the impurity (sulfotep) was 0.003 mg mL^?1 corresponding to the maximum permitted level according to Food and Agricultural Organization of the United Nations (FAO) specifications for the active substance (chlorpyrifos) being 3 g kg^?1 of the chlorpyrifos content found. The main advantage of the proposed method was a considerable reduction in the analysis time since both analytes were determined based on a single injection into the GC-FID. Analysis of real samples of commercial pesticide formulations confirmed fitness-for-purpose of the proposed method.