鲜猪肉中邻苯二甲酸二异辛酯含量的气相色谱检测方法初探

该文采用气相色谱仪对鲜猪肉中邻苯二甲酸二异辛酯(DEHP)的含量进行测定。采用提取、皂化工艺,使DEHP分解为邻苯二甲酸和异辛醇,用水蒸气蒸馏出异辛醇,萃取浓缩进样测定异辛醇的含量,并进一步换算出DEHP含量。结果显示：提取溶剂选用乙醚,提取时间6 h,皂化时间3h,在蒸馏液pH 7条件下,异辛醇萃取率为81.8％～88.0％,方法加标回收率为75.12％～84.95％,检出限为1.07×10^-3 mg/kg。该方法降低了对仪器设备的要求,为制定相关标准、保障食品与包装材料的安全提供了依据。     

影响富营养化湖泊底泥氮、磷释放的因素

[目的]分析水体酸碱度、温度以及上覆水营养盐浓度,为合理评估环境因素对湖泊底泥氮、磷释放的影响提供科学依据。[方法]选择富营氧化比较严重的云南省昆明市城市景观湖泊翠湖为研究区域,通过控制不同pH值、温度和上覆水营养盐浓度来模拟影响底泥氮磷释放的因素。[结果](1)放置时间相同条件下底泥氮、磷释放量受到水体酸碱性的影响,中性环境下(pH=7.5)释放量高于酸性和碱性水体条件。底泥释放5,10h条件下,pH值为7.5时底泥磷释放量分别达到5.88,8.28mg/kg;pH值为7.5时底泥氮释放量分别达到22.8,38.4mg/kg;(2)底泥氮、磷释放量随着温度升高而增加。温度为20℃时底泥氮、磷的释放量分别达到28.62,3.75mg/kg;(3)底泥氮、磷的释放量均随着上覆水浓度增加而减少,随着放置时间延长而增加。放置时间5h上覆水氨氮浓度0.31mg/L底泥氮的释放量最大,达到21.63mg/kg。放置10h在氨氮为2.37mg/L时底泥氮的释放量达到最大值(39.22mg/kg);底泥磷释放量在上覆水磷浓度0.14mg/L时底泥总磷的释放量最大;放置时间为5,10h时分别达到4.25,4.91mg/kg。[结论]底泥中营养盐释放是一相当复杂的动态过程,水体酸碱度、温度或上覆水营养盐浓度是影响释放量的主要因素。     

GC/MS测定微波下塑料包装袋中DEHP对玉米的迁移量

本文采用气相色谱-质谱法(GC-MS)对微波下包装袋迁移到玉米中的邻苯二甲酸二(2-乙基己基)酯(DEHP)的量进行了测定分析,综合分析了提取溶剂、超声提取时间和提取温度等因素对DEHP提取结果的影响。结果表明,提取溶剂选用正己烷,38℃提取30 min可以较好提取玉米中的DEHP。该方法有效缩短了前处理时间,为微波下DEHP迁移含量的检测提供了重要的技术手段。     

纳米氧化锌改性LDPE食品包装薄膜中锌粒子的迁移规律

为探究纳米氧化锌改性(low-density polyethylene,LDPE)薄膜中纳米锌粒子的迁移规律,依照欧盟法规(EU)No.10/2011,分别采用蒸馏水、30 g/L乙酸溶液、体积分数10%的乙醇溶液、体积分数95%的乙醇溶液作为中性、酸性、脂肪性和酒精性食品模拟物,研究在不同温度条件下(40、70℃)纳米锌粒子的迁移情况,同时探究微波和紫外处理对迁移结果的影响。研究发现,纳米锌粒子在4种食品模拟物中的迁移量从高到低依次为:酸性食品模拟物、中性食品模拟物、酒精性食品模拟物和脂肪性食品模拟物,并且随温度的升高,纳米锌粒子的迁移量增大。此外,微波处理能促进纳米锌粒子的迁移,而紫外处理则没有促进效果。纳米锌粒子的迁移量范围为0.52~14.17 mg/kg。根据欧盟规定所允许的最大迁移量5 mg/kg,迁移试验表明纳米氧化锌改性LDPE薄膜还需要进一步开展减少纳米粒子迁移的研究工作,以确保其在食品包装中的安全使用。     

乳酸菌发酵技术脱除大米粉中镉的工艺优化

为了解决镉超标精米的利用问题,该试验以镉质量分数为0.6479 mg/kg的精米为原料,尝试用乳酸菌发酵技术脱除大米粉中的重金属镉,并对发酵工艺进行了优化研究。通过对比试验确定发酵菌种为植物乳杆菌和戊糖片球菌(2∶1,体积比)的混合菌,并通过单因素试验分析了大米粉粒度、发酵温度、发酵时间和接种量对镉的脱除率的影响。在固定大米粉粒度为40目的条件下,利用响应面法优化并确定的工艺参数为:发酵温度40.8℃、发酵时间23.4 h、接种量3%。在此条件下,大米粉中镉的脱除率达85.73%,在发酵后的大米粉中,镉的残留量为0.0925 mg/kg,低于国家限量标准(0.2 mg/kg)。该研究结果能有效地缓解镉超标精米的利用问题以及为工业生产提供参考数据。     

冷却猪肉不同贮藏温度的货架期预测模型

为了建立冷却猪肉货架期的预测模型,把特定腐败菌接种到无污染的冷却猪肉表面,托盘包装分别置于0℃,4℃,7℃,10℃,14℃和20℃的温度下贮藏,分别测定不同贮藏时间的细菌总数,同时对4℃贮藏的不同企业冷却猪肉进行品质分析,确定腐败限控量.结果表明,冷却猪肉腐败限控量为7.23 lg(cfu/g).应用修正的Gompertz函数能很好的描述特定腐败菌在不同温度下的生长动态,建立了6种温度下其在猪肉中的生长模型.温度对最大比生长速率和延滞时间等动力学参数的影响,采用平方根模型呈现良好的线性关系,模型残差值的绝对值均小于0.1,上下浮动于零左右,表明该模型描述的温度与比生长速率和延滞时间是可信的,由此建立了0～20℃范围内冷却猪肉贮藏过程中货架期的预测模型.     

黑碳添加对土壤有机碳矿化的影响

通过室内培养试验,向土壤中分别添加不同温度制备的黑碳,热解温度分别为350℃(T350)、600℃(T600)和850℃(T850),研究了黑碳添加对土壤有机碳矿化的影响。结果表明,不同温度条件制备的黑碳在15℃和25℃培养条件下,土壤CO2释放速率总的趋势是前期分解速率快,后期缓慢。在整个培养过程中(112天),随着培养时间的延长,土壤CO2释放速率下降趋势逐渐降低,CO2释放速率相对值的大小随着培养温度的的升高而增大。在不同温度培养条件下,添加黑碳后土壤CO2-C累计量均是T350>T600>T850,T350土壤CO2-C累计量最高分别为415.26 mg/kg和733.82 mg/kg。添加不同黑碳后,土壤有机碳矿化增加率存在极显著差异(p<0.01),表明不同温度制备的黑碳对土壤有机碳矿化的影响显著。     

邻苯二甲酸酯在不同类型土壤-植物系统中的累积特征研究

选用黄棕壤和红壤,用土壤老化和上海青（Brassica campestris）盆栽试验研究了邻苯二甲酸二正丁酯（Di-butyl Phthalate,DBP）和邻苯二甲酸二异辛酯（D（i2-ethylhexyl）Phthalate,DEHP）在土壤-植物系统中的分布规律。土壤老化试验表明,DBP和DEHP在土壤中的吸附量随着老化时间的增加,呈现开始（0-10 d）老化速率较快,而后（10-30 d）老化速率减小并且老化总量趋于稳定的趋势。盆栽试验结果表明,在红壤上植物体内DBP/DEHP含量（DBP：0.576-2.750 mg.kg-1;DEHP：9.369-33.256 mg.kg-1）与土壤污染浓度呈正相关,生物量与土壤污染浓度呈负相关;而在黄棕壤上,上海青的生物量并不随着土壤DBP/DEHP的添加量的升高而变化,植物体内DBP/DEHP的含量（DBP：0.212-0.401 mg.kg-1;DEHP：0.421-0.490 mg.kg-1）远低于红壤的相同污染浓度处理。在黄棕壤上,上海青对DBP/DEHP的BCF值介于0.061-1.041之间;而在红壤上,BCF值均大于1.0（介于1.175-15.695之间）,具有一定的生物富集作用。通过试验还估算了红壤上DBP/DEHP的临界浓度为6.932-11.718 mg.kg-1,可为建立生态效应预警指标提供参考。     

运输时间和温度对生猪应激和猪肉品质的影响

为了研究运输时间和温度对生猪应激及猪肉品质的影响,该文以三元杂交猪杜长大为研究对象,测定了运输前、运输3、6、9h以及运输温度-10~0℃、0~10℃、10~20℃、20~30℃等条件下生猪的血液生化指标、宰后猪肉p H值、肉色等指标。结果表明:运输6 h后三元猪出现应激反应,9 h以后应激反应显著增强(P0.05),运输6 h以上三元猪与运输3 h相比,宰后45 min p H值显著降低(P0.05),肉色分级显著升高(P0.05),肉品质降低;运输温度低于10℃时三元猪出现应激反应,-10~0℃时应激反应显著增强(P0.05),-10~0℃和20~30℃条件下宰后24 h p H值显著高于0~10℃和10~20℃(P0.05),肉品质降低。因此,为防止生猪运输应激及改善猪肉品质,生猪运输时间应小于6 h,运输温度为10~20℃。该研究结果对屠宰行业减少生猪应激提高猪肉品质提供参考。     

炭化温度和时间与棉杆炭特性及元素组成的相关关系

为了揭示炭化温度和时间对生物质炭特性及元素组成的影响,以棉花秸秆为生物质炭制作原料,对比研究不同炭化温度（300、450、600℃）和时间（0.5、1、2、4、6 h）制备的棉秆炭的pH值、阳离子交换量（CEC）、电导率等特性及有机碳、氮和矿质元素含量及其间的相互关系。结果表明：棉秆炭化出炭率、棉秆炭有机碳含量随炭化温度的升高和时间的延长而降低（出炭率： 48.66%（300℃）>35.39%（450℃）>31.06%（600℃）,有机碳：564.02 g/kg（300℃）>405.94 g/kg（450℃）>259.36 g/kg（600℃）;在300℃下,pH值随着时间的延长而增大,450℃和600℃下基本保持在10.5左右;电导率随炭化温度的升高而增加,在炭化时间内变化不明显,且炭化温度300～450℃对棉秆炭的电导率影响相对较小,600℃影响较大;CEC随炭化温度的升高而降低,在300℃下随炭化时间的延长而增大,450和600℃下则降低。棉秆炭中全磷,全钾,速效钾,钙,镁含量随着温度的升高和时间的延长逐渐增加,全氮和碱解氮则相反,速效磷含量则表现出90.07 mg/kg（450℃）>60.72 mg/kg（600℃）>20.18 mg/kg（300℃）的变化趋势。炭化温度和时间与棉秆炭指标间相关分析表明,炭化温度和时间与出炭率、CEC、有机碳、全氮和碱解氮间呈负相关,与pH值、全磷、全钾、速效磷、速效钾、钙和镁含量呈正相关。综合分析,低温短时间（300℃,1～2h）制备的棉秆炭对农业利用预期效应较好,该研究结论为新疆棉秆炭的制备和农业利用提供理论依据和数据支撑。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.     

Electron donor and pH relationships for biologically enhanced dissolution of chlorinated solvent DNAPL in groundwater

Biologically enhanced dissolution offers a method to speed removal of chlorinated solvent dense non-aqueous-phase liquid (DNAPL) sources such as tetrachloroethene (PCE) and trichoroethene (TCE) from aquifers. Bioremediation is accomplished by adding an electron donor to the source zone where fermentation to intermediates leading to acetic acid and hydrogen results. The hydrogen and possibly acetic acid are used by dehalogenating bacteria to convert PCE and TCE to ethene and hydrochloric acid. Reductive dehalogenation is thus an acid forming process, and sufficient alkalinity must be present to maintain a near neutral pH. The bicarbonate alkalinity required to maintain pH above 6.5 is a function of the electron donor: 800 mg/L of bicarbonate alkalinity is sufficient to achieve about 1.2 mM TCE dechlorination with glucose, 1.7 mM with lactate, and a much higher 3.3 mM with formate. Laboratory studies indicate that in mixed culture, formate can be used as an electron donor for complete conversion to ethene, contrary to pure cultures studies indicating it cannot. Various strategies can be used to add electron donor to an aquifer for DNAPL dehalogenation while minimizing pH problems and excessive electron donor usage, including use of injection-extraction wells, dual recirculation wells, and nested injection-extraction wells.     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Increase in auxiliary photoprotective photosynthetic pigments in wheat seedlings induced by Azospirillum brasilense

Inoculation of wheat seedlings with the plant growth-promoting bacterium Azospirillum brasilense Cd was immobilized in alginate microbeads and, without applying any stress, significantly increased the quantity of several photosynthetic pigments, such as chlorophyll a, chlorophyll b, and the auxiliary photoprotective pigments violaxanthin, zeaxanthin, antheroxanthin, lutein, neoxanthin, and β-carotene. This resulted in greener plants with no apparent visible stress. After monitoring the quantity of photosynthetic pigments for 4 weeks, we observed that inoculated plants had higher quantities of pigments in shoot and stem. The greatest difference in the quantity of all pigments between inoculated and noninoculated plants occurred in the first week of growth. Regardless of treatment, the quantity of pigments in stems was three to four times less than the quantity of these pigments in shoots. Application of Azospirillum, either as liquid inoculant or as alginate microbeads, did not alter the positive effect of the bacteria on pigment production or the positive response of the plants towards A. brasilense Cd inoculation.     

In-situ enrichment and analysis of atrazine-degrading microbial communities using atrazine-containing porous beads

We examined the community composition of microbes that colonized atrazine-containing beads buried in agricultural soils that differed in atrazine treatment history. Bacterial abundance was 5-40-fold greater in atrazine-fortified beads. In beads containing 20 mg atrazine kg⁻¹ buried in soil with a history of atrazine application (conditioned soil), the abundance of Actinobacteria increased approximately 80-fold whereas in control soil, Actinobacteria were enriched only 10-fold and the gamma-Proteobacteria and Planctomycetes increased by 60- and 25-fold, respectively. The gamma-Proteobacteria were enriched by 120- and 230-fold in beads containing 200 mg atrazine kg⁻¹ in conditioned and control soil, respectively. The results demonstrate that BioSep^® beads are a suitable matrix for recruiting a diverse subset of the bacterial community involved in atrazine degradation.