农药残留及微生物在农药降解中的应用与展望

农药在人类防治农作物病虫害、草害等诸方面起到了巨大的贡献，但是因之而来的农药残留问题则对环境和人类健康带来了严重的危害。为解决这一问题，人们进行了大量的研究，其中微生物的降解作用已引起人们的广泛关注。综述了农药残留及微生物在其中的应用及发展情况。     

微生物降解农药的研究进展

在农药的微生物降解研究中,分离构建一种由天然微生物构成的复合系,将其应用于被污染的环境是消除农药污染的一个有效方法。本文综述了环境中降解农药的微生物种类、微生物降解农药的机理、在自然条件下影响微生物降解农药的因素及农药微生物降解研究方面的新技术和新方法。     

天门市大米中有机磷农药残留的暴露风险

通过田间采样与室内分析,对天门市早、中、晚稻米中毒死蜱、三唑磷、氧化乐果和甲胺磷等4种有机磷农药的残留量进行了调查,并对大米质量安全状况与农药最高残留量进行了风险评估。结果表明,大米中有机磷农药残留检出率为12．0％,超标率为4．0％,均为三唑磷残留污染。安全指数法评估结果显示,大米中4种有机磷农药残留量的单项安全指数...     

控制农药残留的几种良方

农药喷洒到作物或土壤中,经过一段时间,由于光照、自然降解、雨淋、高温挥发、微生物分解和植物代谢等作用,绝大部分已消失,但还会有微量的农药残留.残留农药对病、虫和杂草无效,但对人畜和有益生物却会造成危害.在农药使用范围和使用量不断扩大的情况下,控制农药残留,保证人畜安全、健康,已成为需要解决的问题.那么,如何最大限度地控制农药残留呢?     

浙八味中药材中农药残留调查及控制对策

通过对浙八味主产区的调查.发现有些中药材依然受到土壤中的滴滴涕、六六六农药残留的污染.麦冬中滴滴涕(或同系物)残留量较高,主要因过去曾长期、大量使用滴滴涕、六六六,导致种植麦冬的部分土壤中滴滴涕(或同系物)残留量仍较高(最高达1.6mg/kg);在部分中药材和土壤中检测出痕量的六六六残留.仙居白术2个样品和土壤中五氯硝基苯的残留较高,其他部分中药材中检测到很低量的毒死蜱、违禁高毒有机磷农药甲胺磷、氯菊酯等农药残留.除了滴滴涕、六六六外,造成中药材中其他农药残留的原因均为药农违规使用农药.     

中药材上农药应用现状及其炮制加工过程对农药残留的影响

中医药是我国独特的医药资源,中药材作为中医药的重要组成部分,其质量安全广受关注。在中药材病虫草害防治过程中,由于农药不规范使用导致的农药残留问题直接影响着中药材产品质量安全甚至出口贸易。本文对我国中药材上农药登记情况及残留限量(maximum residue limit,MRL) 标准进行了概述,并重点归纳了炮制加工过程对中药材中农药残留的影响,同时就中药材上农药使用和管理等方面的相关问题进行了讨论,提出了降低农药残留污染的相关措施。旨在明确中药材从采收到入口全过程中农药残留的变化规律,以期为加强对中药材中农药残留的控制,降低农药残留污染风险以及为我国中药材上农药使用和管理提供参考。     

农药残留检测技术进展概况

50年代农药残留量分析方法局限于化学法、比色法和生物测定法，检测方法缺乏专一性，灵敏度也不高。50年代未根据有机磷和氨基甲酸酯类农药的毒理学原理，使用胆碱酯酶抑制法，灵敏度高，适应性广，但缺乏专一性。60年代色谱技术的发展，使薄层色谱法在农药残留分析中广泛应用。而气相色谱法的出现推动了农药残留分析的高速发展。高效能的色谱柱可将各组分或杂质分离。高灵敏度和专一性强的检测器解决了早期不能检出的微量农药、代谢物和降解产物的分析。80年代以来，对热不稳定极性农药及其代谢物的残留应用液相色谱分析。有的农药采用往前…     

农药学研究的重要手段——放射性同位素示踪技术

化学农药的不合理使用造成了严重的影响问题和食品污染，影响生态平衡，危害人类健康，利用核技术优势研究和解决农药学问题受到人们越来越多的关注，在过去的几年里，放射性同位素示踪技术及其在我国农药科学中应用研究已取得了较大成就，特别是在放射性同位素化学示记合成技术，利用示踪手段研究在动植物体中的农药残留，降解和代谢，在环境中的行为和归宿，以及农药完全使用技术等方面均在较大进展仅中国农业科学院原子能利用天空     

创新机制 加强监管 全面推进农药登记管理年工作——记天津市农药登记管理工作

2008年，天津市按农业部的统一部署，以保证农业生产和农产品质量安全为中心，以建立健全农药管理的长效机制为重点，解放思想，勇于创新，取得了前所未有的好成绩，达到了预期实现“五无”（即无违法五种高毒有机磷农药生产、无违法五种高毒有机磷农药经营、无违法五种高毒有机磷农药使用、无农药使用后废弃物、供奥农产品中无农药残留超标）的目标。     

黄石市蔬菜农药污染状况及防治对策

黄石市的农药施用量近年来有较大的增长,农药的大量使用带来了严重的污染环境、蔬菜农药残留超标、农业生态环境恶化等问题。加强病虫害的综合防治,推广使用高效、低毒、低残留的农药和安全合理使用农药,是减少因施用农药带来的污染,恢复农业生态的有效途径。     

农药在水介质中的光化学降解研究情况

农药在水环境中会受到理化因子作用发生降解。本文通过对国内外关于水介质中农药光降解机理和影响因素的研究成果加以总结和归纳,阐述水介质中农药光降解的动力学模型、光化学反应类型,以及在水环境中影响农药光降解的主要因素,概述水介质中农药的光降解特性。     

三种新烟碱类杀虫剂在土壤中的残留降解及影响因子

建立了吡虫啉、啶虫脒和噻虫嗪在土壤中的高效液相色谱-串联质谱（HPLC-MS/MS）检测方法。样品经乙腈提取和QuEChERS法净化后，采用HPLC-MS/MS检测，外标法定量，在0.01~1.0 mg/kg添加水平下，3种新烟碱类杀虫剂在土壤中的回收率在89%~103%之间，相对标准偏差（RSD）在1.3%~10.3%之间，定量限均为0.01 mg/kg。采用建立的方法，在室内模拟条件下，研究了土壤微生物、温度、土壤含水量及农药初始浓度对土壤中吡虫啉、啶虫脒和噻虫嗪降解的影响。结果表明:土壤微生物是影响农药残留降解的首要因素，灭菌处理土壤中农药残留降解速率明显低于非灭菌土壤。此外，环境温度、土壤含水量、初始浓度等因素也会对农药残留降解产生不同影响，土壤含水量为最大持水量的60%左右时降解最快，半衰期分别为15.6、7.2和25.8 d；农药初始浓度越高，降解速度越慢；在5~35℃范围内，随着温度的升高，降解速度加快。     

环糊精及其衍生物在农药领域应用的研究进展

环糊精及其衍生物具有 "内疏水、外亲水"的特殊分子结构,可与许多客体分子包结形成包合物。环糊精与农药形成包合物对农药分子具有增溶、控制释放、提高稳定性等功能,在农药制剂方面具有重要的应用价值。环糊精对农药污染物的降解有促进作用,对农药分子具有选择性识别作用,因而在农药污染物治理、农药残留检测方面也有重要的应用价值。综述了环糊精及其衍生物在作为农药剂型加工中的助剂、农药污染物治理和农药残留检测等方面应用的研究新进展,并对其在农药领域的发展趋势和应用前景进行了展望。     

Modeling hydrology, metribuzin degradation and metribuzin transport in macroporous tilled and no-till silt loam soil using RZWQM

Due to the complex nature of pesticide transport, process-based models can be difficult to use. For example, pesticide transport can be effected by macropore flow, and can be further complicated by sorption, desorption and degradation occurring at different rates in different soil compartments. We have used the Root Zone Water Quality Model (RZWQM) to investigate these phenomena with field data that included two management conditions (till and no-till) and metribuzin concentrations in percolate, runoff and soil. Metribuzin degradation and transport were simulated using three pesticide sorption models available in RZWQM: (a) instantaneous equilibrium-only (EO); (b) equilibrium-kinetic (EK, includes sites with slow desorption and no degradation); (c) equilibrium-bound (EB, includes irreversibly bound sites with relatively slow degradation). Site-specific RZWQM input included water retention curves from four soil depths, saturated hydraulic conductivity from four soil depths and the metribuzin partition coefficient. The calibrated parameters were macropore radius, surface crust saturated hydraulic conductivity, kinetic parameters, irreversible binding parameters and metribuzin half-life. The results indicate that (1) simulated metribuzin persistence was more accurate using the EK (root mean square error, RMSE = 0.03 kg ha(-1)) and EB (RMSE = 0.03 kg ha(-1)) sorption models compared to the EO (RMSE = 0.08 kg ha(-1)) model because of slowing metribuzin degradation rate with time and (2) simulating macropore flow resulted in prediction of metribuzin transport in percolate over the simulation period within a factor of two of that observed using all three pesticide sorption models. Moreover, little difference in simulated daily transport was observed between the three pesticide sorption models, except that the EB model substantially under-predicted metribuzin transport in runoff and percolate >30 days after application when transported concentrations were relatively low. This suggests that when macropore flow and hydrology are accurately simulated, metribuzin transport in the field may be adequately simulated using a relatively simple, equilibrium-only pesticide model.     

电化学氧化法降解高浓度氧乐果农药废水的研究

采用三维屯极电化学法对模拟氧乐果农药废水进行降解研究,考察了在各种实验条件各参数对氧乐果去除率的影响,确定了操作最佳条件为电压:20V,pH值:3,进水浓度:450mg/L,反应时间30min.此法适用于对高浓度氧乐果农药废水的预处理过程.     

Considering degradation kinetics of pesticides in plant uptake models: proof of concept for potato

BACKGROUND

Degradation kinetics of pesticides in plants are crucial for modeling mechanism-based pesticide residual concentrations. However, due to complex open-field conditions that involve multiple pesticide plant uptake and elimination processes, it is difficult to directly measure degradation kinetics of pesticides in plants. To address this limitation, we proposed a modeling approach for estimating degradation rate constants of pesticides in plants, using potato as a model crop. An operational tool was developed to backward-estimate degradation rate constants, and three pesticides were selected to perform example simulations.

RESULTS

The simulation results of thiamethoxam indicated that the growth dynamics of the potato had a significant impact on the degradation kinetic estimates when the pesticide was applied during the early growth stage, as the size of the potato determined the uptake and elimination kinetics via diffusion. Using mepiquat, we demonstrated that geographical variations in weather conditions and soil properties led to significant differences in the dissipation kinetics in both potato plants and soil, which propagated the variability of the degradation rate constant. Simulation results of chlorpyrifos differed between two reported field studies, which is due to the effect of the vertical distribution of the residue concentration in the soil, which is not considered in the majority of recent studies.

CONCLUSIONS

Our proposed approach is adaptable to plant growth dynamics, preharvest intervals, and multiple pesticide application events. In future research, it is expected that the proposed method will enable region-specific inputs to improve the estimation of the degradation kinetics of pesticides in plants. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

糙皮侧耳菌丝培养液对4种农药的降解活性

为明确食用菌培养液对农药污染物的降解活性，运用液相色谱-串联质谱仪 (LC-MS/MS) 和超高效液相色谱仪-附带二级阵列管检测器 (UPLC-PDA) 技术，测定了乐果、啶虫脒、高效氯氟氰菊酯和多菌灵4种农药在糙皮侧耳液体培养基中的降解动态及随漆酶活性变化情况。结果表明:4种农药在培养液中残留降解动态符合一级动力学模型，高效氯氟氰菊酯、多菌灵、乐果和啶虫脒的降解半衰期分别为2.93、4.38、11.83和14.01 d，降解速率由高到低为高效氯氟氰菊酯 > 多菌灵 > 乐果 > 啶虫脒。灭菌后培养液中漆酶活性消失，农药降解速率降低。在1 h和4 h时，粗酶液浓度越高，农药降解率越大，4种农药的降解率与漆酶活性符合ExpDec1型函数关系。本研究证实了糙皮侧耳培养液对4种农药的降解具有促进作用，初步揭示了漆酶具有降解农药的活性，为糙皮侧耳降解农药资源开发提供了技术支持。     

大棚中百菌清等4种农药在小白菜上的降解规律研究

研究了小白菜栽培过程中,百菌清、敌敌畏、氧化乐果和抗蚜威在不同施用剂量条件下的农药降解动态规律,结果表明,不同农药在小白菜中的残留量和降解速度有较大差异。4种农药施药后在小白菜上的残留量随喷药时间的推移而减少,抗蚜威降解速度最慢,氧化乐果降解速度最快。     

Pesticide degradation in a 'biobed' composting substrate

Pesticides play an important role in the success of modern farming and food production. However, the release of pesticides to the environment arising from non-approved use, poor practice, illegal operations or misuse is increasingly recognised as contributing to water contamination. Biobeds appear to offer a cost-effective method for treating pesticide-contaminated waste. This study was performed to determine whether biobeds can degrade relatively complex pesticide mixtures when applied repeatedly. A pesticide mixture containing isoproturon, pendimethalin, chlorpyrifos, chlorothalonil, epoxiconazole and dimethoate was incubated in biomix and topsoil at concentrations to simulate pesticide disposal. Although the data suggest that interactions between pesticides are possible, the effects were of less significance in biomix than in topsoil. The same mixture was applied on three occasions at 30-day intervals. Degradation was significantly quicker in biomix than in topsoil. The rate of degradation, however, decreased with each additional treatment, possibly due to the toxicity of the pesticide mixture to the microbial community. Incubations with chlorothalonil and pendimethalin carried out in sterile and non-sterile biomix indicated that degradation, rather than irreversible adsorption to the matrix, was the main mechanism responsible for the reduction in recovered residues. Results from these experiments suggest that biobeds offer a viable means of treating pesticide waste.