Removal of Atrazine Contamination in Soil and Liquid Systems Using Bioaugmentation

Reported levels of atrazine in soils at pesticide mix-load sites can vary between 7·9×10^-5 mM and 1·9 mM . We report on a mixed microbial culture, capable of degrading concentrations of atrazine in excess of 1·9 mM . At initial concentrations of 0·046 M and 0·23 M , the mixed population degraded 78% and 21% of atrazine in soil (100 days), respectively. At the same initial concentrations in liquid cultures, 90% and 56% of the atrazine was degraded (80 days), respectively. Decreased degradation in soil samples may have resulted from atrazine sorption to soil surfaces or decreased contact between the population and the herbicide. In the 0·23 M system, we attribute incomplete degradation to phosphorous depletion. Data for carbon dioxide evolution was fitted to a three-half-order regression model, but we feel that there are limitations of the application of this model to atrazine degradation. The population uses the herbicide as a nitrogen source and little carbon is incorporated into biomass, as the energy status of carbons in the ring leads to their direct evolution as [¹⁴C]carbon dioxide. This situation contributes to an evolution pattern that, when fitted to the three-half-order model, results in underestimation of the biomass produced. Data from our study suggest that our mixed culture could be used for bioremediation of atrazine at concentrations up to and exceeding those currently reported for agrochemical mixing-loading facilities. © 1997 SCI.     

莠去津微生物降解的研究进展

综述了莠去津降解微生物的筛选方法、降解速度的影响因素、降解机理,并对农药降解微生物的应用前景进行了展望。对降解农药微生物的研究不但可以得到消除莠去津环境污染的菌株和相应的酶制剂,而且对于抗莠去津转基因技术的研究也有促进作用。     

莠去津在土壤及作物中残留量测定

本文建立了一种土壤和作物中痕量莠去津的高效液相色谱分析方法,比较了超声波提取与振荡提取的回收率,研究了弗罗里硅土净化效果。以甲醇：水（８０／２０,Ｖ／Ｖ）为流动相,检测波长２３５ｎｍ,在ＯＤＳ柱上实现了莠去津与杂质的良好分离。方法简单,分析速度快,测定费用低,检测限为２４ｎｇ／ｇ,回收率为９５％～９７％。     

莠去津在土壤中的残留动态和淋溶动态

利用HPLC法对土壤中莠去津的残留动态、淋溶动态进行了研究。结果显示,莠去津以有效成分2.25 kg/hm2和4.50 kg/hm2的剂量施用时,在土壤中的半衰期分别为19.1 d和18.1 d,即其半衰期与莠去津的施用浓度无关,属于典型的一级动力学反应。在120 d的玉米生长期中,土壤中莠去津在不断降解代谢的同时,逐渐向深层土壤中淋溶,多数莠去津持留在表层土壤中。施用莠去津27 d后,高浓度处理小区莠去津的淋溶深度超过30 cm,深度为10~15 cm处的土壤在施用后27 d莠去津的浓度最大。同一土壤深度,莠去津在高浓度处理小区的残留量要远高于低浓度处理小区。这些结果显示,减小莠去津的用量可以减少莠去津在土壤中的移动,表明低剂量施用莠去津是保护地下水免受污染的一种有效措施。影响莠去津的淋溶作用的主要因素包括使用量和土壤的理化特性。     

Enhanced Mineralization of [14C]Atrazine in Kochia scoparia Rhizospheric Soil from a Pesticide-Contaminated Site

Mineralization of atrazine (6-chloro-N²-ethyl-N⁴-isopropyl-1,3,5- triazine-2,4-diamine) in soil treated with a mixture of atrazine and metolachlor (2-chloro-6′-ethyl-N-(2-methoxy-1-methylethyl)acet-o-toluidide at concentrations typical of point-source contamination (50 μg g⁻¹ each) was significantly greater (P<0·001) in rhizospheric soil from Kochia scoparia (L.) Roth., a herbicide-resistant plant, than in non-vegetated and control soils. Soils were collected from an agrochemical dealership contaminated with several herbicides, including atra-zine, metolachlor, trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine and pendimethalin (N-(1-ethylpropyl)-2,6-dinitro-3,4-xylidene), at concentrations well exceeding the field application rates. Mineralization rates of ring-labeled atrazine in both rhizospheric and non-vegetated soils were quite high (>47% of the initial ¹⁴C applied after 36 days) compared to literature values. These results suggest that plants such as Kochia might be managed at pesticide-contaminated sites to help facilitate microbial degradation of wastes such as atrazine in soil.     

Degradation of [14C]Terbuthylazine and [14C]Atrazine in Laboratory Soil Microcosms

The degradation and formation of major chlorinated metabolites of terbuthylazine and atrazine in three soils (loamy clay, calcareous clay and high clay) were studied in laboratory experiments using molecules labelled with ¹⁴C on the s-triazine ring. Soil microcosms were treated with the equivalent of 1 kg ha^-1 of herbicide and incubated in the dark for 45 days at 20(±1)°C. The quantity of [¹⁴C]carbon dioxide evolved in the soils treated with atrazine was negligible and could not be attributed to mineralization of the parent molecule. The mineralization of terbuthylazine accounted for 0·9–1·2% of the initial radioactivity. In the soils studied, the extrapolated half-lives varied from 88 to 116 days for terbuthylazine and 66 to 105 days for atrazine, with no significant differences for the three soils and the two molecules. The deethyl metabolites of the two s-triazines and the deisopropyl-atrazine metabolite appeared during the incubation in the three soils. The completely dealkylated metabolite was not detected in any of the soils. After 45 days of incubation, the non-extractable soil residues for the high clay, loamy clay and calcareous clay soils represented for terbuthylazine, 33·5, 38·3 and 43·1% and for atrazine, 19·8, 20·8 and 22·3% of the initial radioactivity. © 1997 SCI.     

HPLC法测定土壤中莠去津残留量方法的改进

本文对高效液相色谱法（HPLC）测定土壤中莠去津残留量的方法进行了改进，土壤中莠去津的甲醇提取液经净化柱净化后进样，可消除杂质的干扰，使样吕峰基线稳定，峰形完整，检测限为5ng/g，回收率在92%以上。     

Evidence for the Accelerated Degradation of Isoproturon in Soils

The herbicide isoproturon was degraded rapidly in a sandy loam soil under laboratory conditions (incubation temperature, 15°C; soil moisture potential, -33 kPa). Degradation was inhibited following treatment of the soil with the antibiotic chloramphenicol, but unaffected by treatment with cycloheximide, thus indicating an involvement of soil bacteria. Rapid degradation was not observed with other phenylurea herbicides, such as diuron, linuron, monuron or metoxuron incubated in the same soil under the same experimental conditions. Three successive applications of isoproturon to ten soils differing in their physicochemical properties and previous cropping history induced rapid degradation of the herbicide in most of them under laboratory conditions. There were, however, no apparent differences in ease of induction of rapid degradation between soils which had been treated with isoproturon for the last five years in the field and those with no pre-treatment history. A mixed bacterial culture able to degrade isoproturon in liquid culture was isolated from a soil in which the herbicide degraded rapidly.     

除草剂莠去津对环境的污染及治理

本文综述了除草剂莠去津的环境污染情况及其对水生生物、陆生动物和植物的影响,并提出了制定相关标准,合理施药,使用替代药剂,提高农民的施药技术水平和生物修复的治理措施,更好地发挥其在农业生产上的积极作用。     

氰津·莠30%悬浮剂的气相色谱分析

本文采用气相色谱法,使用CP7906X;英毛细管柱和FID检测器,对混剂中的氰草津和莠去津进行分离与定量。邻苯二甲酸二正丁酯为内标物。分析结果表明氰草津和莠去津的线性相关系数分别为0．99995、0．99999;标准偏差分别为0．23、0．16：变异系数分别为1．49％、1．06％;回收率分别在98．94～100．11％和98．38～101．51％之间。     

阿特拉津高效降解菌的分离与筛选

土样采自河北、山东一些农药厂排污口,通过室内阿特拉津无机盐培养基的驯化培养,分离得到4株在无机盐培养基上对阿特拉津有明显降解圈的降解细菌。底物阿特拉津浓度为1000mg/L,反应体系50ml,体系菌浓度为8.9×107cfu/ml,恒温30℃,180r/min,培养7d,其室内降解效率分别为40.6%、75.7%、82.3%、96.9%。其中菌株BZB-11的降解效率最高。对菌株BZB-11进行降解动态考察,结果显示,BZB-11菌株在无机盐液体培养基中(阿特拉津底物浓度为1000mg/L,反应体系50ml,体系菌浓度6.59×109cfu/ml,恒温30℃,180r/min),对阿特拉津1~3d的降解速度较快,3d可达89.5%,7d的降解率达100%。综合来看,该菌株是一株很有应用前景的高效菌株。     

Potential Dissipation of Atrazine in the Soil Unsaturated Zone: a Comparative Study in Four European Countries

A European-wide project has been undertaken to establish the potential for dissipation of atrazine in the soil subsurface environment. Samples were obtained, avoiding contamination, in four countries (Belgium, Greece, Hungary and UK) and laboratory studies carried out. In order to make comparisons between results from each laboratory, a ring experiment was carried out using common methodology for sampling, extraction and analytical techniques. Subsurface materials from each country were distributed to the other countries. Atrazine dissipation was determined in each country for all materials under the same laboratory conditions. The results of this comparative study showed generally good agreement between all laboratories. Significant potential microbiological dissipation was detected in certain samples. Where differences occurred between laboratories this was attributed to small, spatially heterogeneous microbial populations in the subsurface materials. © 1997 SCI.     

异丙·莠悬浮剂的气相色谱分析方法

本文介绍了用５％ＯＶ－１０１,长度为１ｍ的玻璃填充柱,以正二十碳烷为内标物,在１８０℃的柱温下用ＦＩＤ检测器对异丙·莠悬浮剂中有效成分异丙甲草胺及莠去津同时进行定量分析。分析测得异丙甲草胺变异系数为０．３０７％,平均回收率１００．１１％,线性相关系数０．９９９９;莠去津的变异系数为０．４１６％,平均回收率９９．９７％,线性相关系数０．９９９９。     

莠去津的药害问题及药害防范技术研究概述

本文概述了使用莠去津以来，有关该药的药害情况及药害解除方法的研究状况。     

特丁津与扑草净、莠去津活性比较

温室盆栽条件下,以扑苹净、莠去津分别为对照药剂,研究了特丁津对马唐（Digitaria sanguinalis）、反枝苋（Amaranthus retroflexus）、马齿苋（Portulaca olercea）和稗草（Echinochloa crus-galli）的除草活性。结果表明：3种除草对阔叶杂草的防效都优于对禾本科杂草的防效．特丁津对马唐、稗草、反枝苋、马齿苋4种杂草的防治效果都高于莠去津和扑草净。     

土壤退化与草地退化关系的研究

内蒙古草原在畜牧业生产及环境生态上均占有重要的地位 ,但草地退化比较严重 ,土壤是草地生态系统的基础环境 ,土壤退化与草地退化关系十分密切 ,都受到自然因素与生产活动的影响 ,但土壤退化比草地上植被的退化缓慢 ,土壤具有较强的抗拒退化的能力 ,它是土壤性质的综合表现 ,可以称之为土壤稳定性 ,土壤的稳定性是支撑草地生产稳定和恢复的重要因素 ,在评价与改良退化草地时 ,要充分了解土壤的退化程度 ,引起退化的主导因子 ,因地制宜地采取措施才能收到良好的效果     

灌溉对心底土积盐层的溶解作用

1.心底土积盐层是引起土壤次生盐渍化不可忽略的原因土壤次生盐渍化是干旱、半干旱地区作物正常生长和发展农业生产的一个重要限制因素,综合目前的研究资料,人们对土壤次生盐渍化的发生和防治作了大量的研究工作,但对心底土积盐层与土壤次生盐渍化研究得较少,忽略了这个问题。正如罗赞诺夫指出:“人们往往忽略了土壤以及底土的原始含盐量在灌区土壤次生盐渍化中的作用,因此,我们愿意再一次强调指出,必须重视自然条件特别是土壤的原生盐渍化在次生盐渍化中的重大意义和作     

气相色谱法测定玉米中莠去津和丁草胺农药残留

采用丙酮和石油醚(1:1)提取玉米中莠去津、丁草胺的农药残留,用中性氧化铝进行柱净化,气相色谱法(NPD检测器)进行测定,2种农药的回收率在85.44～95.71%之间,变异系数在4.44～15.19%之间,莠去津的最低检出限为0.004mg/kg,丁草胺的最低检出限为0.016mg/kg。     

异丙草胺·莠去津混配比例筛选及其悬乳剂的研究

氯代酰胺类与三氮苯类除草剂混配是减少后者对玉米田后茬作物药害的有效方法之一。选用异丙草胺和莠去津复配对玉米田主要杂草马唐Digitaria sanguinalis (L.) Scop.、大狗尾草Setaria faberii、马齿苋Portulaca oleracea等的室内防除效果配方筛选试验证明,异丙草胺∶莠去津质量比为18∶23(配方B)时其共毒系数大于100;对所选混配比例实验室配制悬乳剂的主要技术指标研究证明:配方B的主要技术指标如悬浮率、倾倒性、稳定性等均符合行业标准。