阿特拉津生产废水排放对水稻危害的风险分析

阿特拉津是目前世界上广泛使用的除草剂之一,在我国主要使用于东北和华北地区。近年来我国一些地区接连发现了灌溉含有阿特拉津河水的水稻疫苗受害事件。以河北省宣化农药厂的生产工艺为例,通过使用概率评价的方法,进行了阿特拉津对水稻危害的风险分析研究结果表明,这种风险不仅与工厂废水中阿特拉津的排放有关,而且还取决于河水的流量及其风险率所得结果与该厂历史上的实际情况相吻合。     

阿特拉津在土壤中的环境行为研究进展

概述了阿特拉津在土壤中的迁移、降解及其对植物的影响等环境行为,阐述了土壤组成、土壤pH值以及温度、湿度等因素对各种环境行为过程的影响,并结合目前国内外的研究现状,提出了阿特拉津环境行为新的研究方向。     

共存污染物对阿特拉津在天然沉积物上吸附的影响

实验研究了重金属和表面活性剂对阿特拉津在沉积物上吸附的影响.结果表明,Cu2 和Cd2 在低浓度时对阿特拉津吸附无影响或降低其吸附,高浓度时则能明显或轻微促进其吸附.在实验浓度范围内,与对照相比,表面活性剂十二烷基苯磺酸钠(SDBS)和十六烷基三甲基溴化铵(CTAB)抑制阿特拉津的吸附,而Span 20则在低浓度时(≤1mg·L-1)抑制阿特拉津的吸附,高浓度时(>1mg·L-1)促进其吸附.     

灭草松和莠去津在土壤中的竞争吸附

采用振荡平衡法测定了低浓度范围内(＜30 mg·L-1)灭草松和莠去津单、双溶质在4种土壤中的吸附等温线.单溶质吸附结果表明,4种土壤中灭草松存在不吸附、吸附2种类型,吸附等温线类型有L和C型;莠去津的吸附等温线有L、S和C型;有机质、矿物质及农药疏水性是影响灭草松和莠去津在土壤中吸附的重要因素.通过比较单溶质和双溶质溶液中灭草松和莠去津的等温吸附线,发现混合溶液中它们的吸附行为相互之间随土壤类型不同存在竞争、无影响和协同作用,并且竞争程度与溶质浓度有关.用理想溶液吸附理论(IAST)和单溶质吸附等温线参数,模拟了双溶质溶液中灭草松和莠去津的吸附等温线,结果显示,该模型不能很好的预测实验结果.进一步结合吸附机理分析认为,不同土壤中的竞争结果是由于2种农药在其中共同占有吸附点的情况不同造成的.     

Runoff and leaching of atrazine and alachlor on a sandy soil as affected by application in sprinkler irrigation

Abstract

Rainfall simulation was used with small packed boxes of soil to compare runoff of herbicides applied by conventional spray and injection into sprinkler‐irrigation (chemigation), under severe rainfall conditions. It was hypothesized that the larger water volumes used in chemigation would leach some of the chemicals out of the soil surface rainfall interaction zone, and thus reduce the amounts of herbicides available for runoff. A 47‐mm rain falling in a 2‐hour event 24 hours after application of alachlor (2‐chloro‐N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl)‐acetamide) and atrazine (6‐chloro‐N‐ethyl‐N‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine) was simulated. The design of the boxes allowed a measurement of pesticide concentrations in splash water throughout the rainfall event. Initial atrazine concentrations exceeding its’ solubility were observed. When the herbicides were applied in 64000 L/ha of water (simulating chemigation in 6.4 mm irrigation water) to the surface of a Tifton loamy sand, subsequent herbicide losses in runoff water were decreased by 90% for atrazine and 91% for alachlor, as compared to losses from applications in typical carrier water volumes of 187 L/ha. However, this difference was not due to an herbicide leaching effect but to a 96% decrease in the amount of runoff from the chemigated plots. Only 0.3 mm of runoff occurred from the chemigated boxes while 7.4 mm runoff occurred from the conventionally‐treated boxes, even though antecedent moisture was higher in the former. Two possible explanations for this unexpected result are (a) increased aggregate stability in the more moist condition, leading to less surface sealing during subsequent rainfall, or (b) a hydrophobic effect in the drier boxes. In the majority of these pans herbicide loss was much less in runoff than in leachate water. Thus, in this soil, application of these herbicides by chemigation would decrease their potential for pollution only in situations where runoff is a greater potential threat than leaching.     

Atrazine degradation in a containerized rhizosphere system

Abstract

The effect of atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine) on rhizosphere microorganisms and its fate in a containerized rhizosphere system was studied. The rhizosphere system consisted of corn grown in pot containing a defined potting mix of sand and bark with atrazine. Sterilized potting mix and a container without plants served as controls. Atrazine was extracted and analyzed via HPLC. Fluorescent pseudomonad populations increased 100‐fold in the rhizposphere during a 60‐day incubation period as compared to the nonvegetated control. Atrazine degradation was higher in the rhizosphere system (half‐life of 7 days) compared to the nonvegetated control (half‐life of greater than 45 days). The major degradation product detected in the rhizosphere system was deisopropylatrazine; other products detected included deethylatrazine, deethylhydroxyatrazine, deisopropylatrazine and hydroxyatrazine. Hydroxyatrazine was detected in the nonvegetated and sterile controls. The containerized rhizosphere system provides an experimental system to study the fate of pesticidal chemicals as well as the effects on microbial populations.     

Glutathione peroxidases in Lolium multiflorum and Festuca arundinacea: Activity,susceptibility to herbicides and characteristics

To evidence a possible mechanism of defense toward oxidative stress induced by herbicides in plants, an investigation was carried on the activity of glutathione peroxidase (GPX) in Italian ryegrass (Lolium multiflorum) and in Festuca (Festuca arundinacea) in response to atrazine (6-chloro-N-ethyl-N′-isopropyl-1,3,5-triazine-2,4-diamine) and fluorodifen (4-nitrophenyl α,α,α-trifluoro-2-nitro-p-tolyl ether). In general, the herbicide treatments significantly induced GPX activity in the shoots of Italian ryegrass, whereas inhibited it in Festuca. These opposite behaviors are examined, taking into account the accumulation and persistence of the two herbicides in the plants, and they are discussed in terms of GPX counteraction to oxidative stress in the first case, and of a lower detoxification rate unable to prevent a deleterious effect on the GPX activity in the second case. Further information on the properties of Italian ryegrass and Festuca GPX were achieved by purification and isolation of the enzymes, performed by protein liquid chromatography and by electrophoretic analyses. GPX of both the plants were found to be heterodimer with multiple function in showing also glutathione S-transferase (GST) activity.     

Kinetic and isotherm error optimization studies for adsorption of atrazine and imidacloprid on bark of Eucalyptus tereticornis L.

The aim of this study was to establish the bark of Eucalyptus tereticornis L. (EB) as a low cost bio-adsorbent for the removal of imidacloprid and atrazine from aqueous medium. The pseudo-first-order (PFO), pseudo-second-order (PSO), Elovich and intra-particle diffusion (IPD) models were used to describe the kinetic data and rate constants were evaluated. Adsorption data was analysed using ten 2-, 3- and 4-parameter models viz. Freundlich, Jovanovic, Langmuir, Temkin, Koble–Corrigan, Redlich–Peterson, Sips, Toth, Radke–Prausnitz, and Fritz-Schluender isotherms. Six error functions were used to compute the best fit single component isotherm parameters by nonlinear regression analysis. The results showed that the sorption of atrazine was better explained by PSO model, whereas the sorption of imidacloprid followed the PFO kinetic model. Isotherm model optimization analysis suggested that the Freundlich along with Koble–Corrigan, Toth and Fritz-Schluender were the best models to predict atrazine and imidacloprid adsorption onto EB. Error analysis suggested that minimization of chi-square (χ²) error function provided the best determination of optimum parameter sets for all the isotherms.     

Hydrolysis kinetics of atrazine and influence factors

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除草剂阿特拉津的环境毒理研究进展

叙述了阿特拉津的应用概况及其在生产实践中所存在问题;阿特拉津在生物体内和环境中的降解代谢过程。综述了近年来国内外在阿特拉津的残留分析方法、环境毒理学和微生物降解等方面的研究进展。