鼠李糖脂对苯系物污染含水层的修复效果研究

通过模拟污染介质的静态脱附实验和一维模拟柱冲洗实验，对比了鼠李糖脂、Tween-80、TX-100对苯的修复效果，筛选出最优表面活性剂进行实际污染土样修复，确定最佳修复技术参数。结果表明：3种表面活性剂对苯的脱附效果为鼠李糖脂>Tween-80>TX-100。采用鼠李糖脂淋洗液进行实际污染土样动态冲洗修复时，鼠李糖脂质量分数宜为0.20%,冲洗流速不宜超过14.4 mL/d,淋洗液冲洗量宜为4倍孔隙体积(PV),在此条件下苯的出流质量浓度最低可达到0.29 mg/L。在实际污染场地修复应用时，修复后应持续注入2倍PV以上的清水冲洗出残留污染物和修复药剂，研究结果可为苯系物污染含水层的表面活性剂修复提供理论指导和技术支撑。     

产糖脂类生物表面活性剂菌株鉴定及发酵条件优化

从胜利油田污水中筛选出的产生物表面活性剂菌株Bbai-1,经过生理生化鉴定及16S rDNA系统发育学分析确定其属于类短短芽孢杆菌属(Brevibacillus parabrevis),由建立的该菌株的系统发育树可知菌株Bbai-1与其他类短短芽孢杆菌类同源性较低,是一个新的种.薄层色谱和红外光谱分析结果表明此菌株所产的生物表面活性剂为一种新型的糖脂类生物表面活性剂.通过产量和表面张力双重指标对菌株Bbai-1产生物表面活性剂的条件进行优化,确定了其最佳发酵温度为25℃、盐度为8 g/L、pH为7.5.在最佳发酵条件下,生物表面活性剂的产量可达0.9764 g/L.此糖脂类生物表面活性剂具有较高的降低表面张力能力,在浓度为其临界胶束浓度(120 mg/L)时,可将水溶液的表面张力从66.15 mN/m降低至27.62 mN/m.     

假单胞菌L-01产表面活性剂的性能分析

通过对活性部位测定,表明菌株L-01产的生物表面活性剂主要是胞外型的糖脂类物质;提取生物表面活性剂后,采用红外扫描仪和紫外扫描仪测定其结构并进一步分析表明,该生物表面活性剂为鼠李糖脂。当以柴油为惟一碳源培养菌株L-01时,在生长的对数后期开始产鼠李糖脂,并在稳定期的初期达到最大值。菌株L-01产的鼠李糖脂对柴油具有良好的乳化能力,培养60 h时,其E24值高达95.2%。通常表面活性剂的临界胶束浓度(CMC)是指在水中测得的,而对鼠李糖脂在水中和土壤中的测定其CMC值后,结果发现两者差距很大,在水中的CMC为65 mg/L;而在土壤溶液中时,其CMC值高达185 mg/L,这一点对利用生物表面活性剂于石油污染生物修复具有重要的参考价值,因为添加的表面活性剂在高于CMC值时才能有效地提高生物修复效率。     

表面活性剂清洗处理重度石油污染土壤

为了优化表面活性剂清洗处理重度石油污染土壤的方法和具体洗脱条件参数,采集山东省东营市胜利油田污染土壤,研究了阴离子-非离子混合表面活性剂对该土壤中石油类污染物的去除效果。应用化学热洗原理,主要考查了表面活性剂配比、投加量、清洗温度及清洗助剂对去除效果的影响。实验得到的清洗处理最佳条件为：使用LAS与TX-100质量比为8∶2的组合表面活性剂,总表面活性剂浓度为3 g/L,助剂硅酸钠浓度为5 g/L,75℃条件下搅拌1 h。清洗后土壤含油量从20%下降到4.6%,去除率达到76.9%。废水回用实验表明,清洗处理的废水对土壤中石油烃类物质仍有一定的去除效果。废水回用比从30%到100%时,对土壤中石油烃的去除率都可达到55%以上。对废水进行二次回用时仍能去除18.8%的污染物。     

两种生物表面活性剂对污染塿土中苯酚的淋洗修复研究

为探讨两种生物表面活性剂皂苷和鼠李糖脂对污染塿土中苯酚的淋洗修复机制,采用批次试验方法,初步探究了塿土对苯酚及两种生物表面活性剂的吸附特征、两种生物表面活性剂在不同淋洗条件(生物表面活性剂浓度、时间、温度)下对塿土中苯酚的淋洗效果。结果表明:(1)塿土对苯酚的吸附量较低,吸附等温线符合Langmuir等温方程;(2)在较低浓度范围,塿土对皂苷和鼠李糖脂的吸附属于单分子层物理吸附,能较好地用Langmuir等温方程拟合;(3)塿土对鼠李糖脂的吸附与其对苯酚的吸附在相同的数量级,在研究鼠李糖脂对塿土中苯酚的淋洗时应予以考虑,塿土对皂苷的吸附与其对苯酚的吸附相比可以忽略;(4)室温(25℃)下,塿土对皂苷和鼠李糖脂两种生物表面活性剂的吸附量最小;(5)两种生物表面活性剂对塿土中苯酚的最佳淋洗条件为:淋洗时间8h,温度25℃,皂苷和鼠李糖脂的质量浓度分别为0.5、0.6g/L;对于轻度污染塿土,两者对苯酚的淋洗率均可达到100.00%,而对中度和重度污染塿土修复效果相对不佳。     

表面活性剂对Cd2+在沉积物上吸附行为的影响

以Cd2+为重金属代表,阴离子表面活性剂十二烷基苯磺酸钠(SDBS)、阳离子表面活性剂氯化十六烷基吡啶(CPC)、非离子表面活性剂辛基酚聚氧乙烯醚(TX-100)为表面活性剂代表,用实验模拟法研究了3种类型的表面活性剂对Cd2+在沉积物上吸附行为的影响.结果表明,不同种类的表面活性剂对Cd2+在沉积物上的吸附影响不同,SDBS对Cd2+的吸附影响可分为2个阶段,当SDBS初始质量浓度从0 mg/L增加到2 600 mg/L,Cd2+的吸附量从1.52 mg/g增至1.88 mg/g,增加了23.7%,随着SDBS初始浓度继续增加,Cd2+的吸附量开始下降,当SDBS初始质量浓度增至16 000 mg/L,Cd2+的吸附量降低至0.34 mg/g;CPC主要通过在溶液中电离出CP+,CP+与Cd2+竞争沉积物表面的吸附位从而抑制Cd2+的吸附,当CPC初始质量浓度从0 mg/L增加至16 000 mg/L,Cd2+的吸附量从1.50 mg/g降低至0.52 mg/g;TX-100能轻微抑制Cd2+在沉积物上的吸附,当TX-100初始质量浓度从0 mg/L增加到16 000 mg/L时,Cd2+吸附量从1.52 mg/g减少至1.35 mg/g.     

鼠李糖脂对不同菌株降解柴油污染物的影响

通过一系列实验分析了鼠李糖脂对柴油污染物生物降解的影响。单菌株柴油降解实验结果表明,在添加生物表面活性剂鼠李糖脂后,各菌株细胞表面疏水性均发生不同程度的增加,并且对柴油的降解率均有所提高。在混合菌的柴油污染物降解实验中,发现当向土壤中添加了200 mg/L鼠李糖脂时,对柴油的降解才有较大的提高;而当添加100 mg/L的鼠李糖脂到水体中时,对柴油的降解就有较大的提高,而当鼠李糖脂浓度提高为200 mg/L时,柴油的降解率却没有进一步明显的提高。这说明鼠李糖脂对柴油降解的影响程度不仅与环境介质有关,还与添加的鼠李糖脂浓度有关。进一步分析表明,添加适当浓度的鼠李糖脂不仅可以提高对柴油的降解率,而且可加速其降解速度,缩短生物修复所需时间。     

生物与化学表面活性剂协同洗脱土壤中PCBs的研究

通过序批实验和土柱淋洗实验研究了由生物表面活性剂鼠李糖脂(RL)与非离子化学表面活性剂十二烷基醇聚氧乙烯(6)醚(POE(6))混合得到的复配试剂洗脱污染土壤中多氯联苯(PCBs)的作用效果及其作用机理。结果表明,同一土样中,从批实验得到的PCBs洗脱率略高于土柱淋洗实验。RL与POE(6)两种单一试剂对人工污染土样中的PCBs洗脱率均大于60%,而对陈化土样中的洗脱率均不到20%,且土壤中的TOC含量越高,PCBs的洗脱率越低。在质量浓度为301 mg/L(10 CMC)及1 505 mg/L(50 CMC)的RL-POE(6)复配试剂中,RL与POE(6)对人工污染土壤中PCBs的洗脱具有一定的协同作用。当复配试剂的浓度为301 mg/L时,RL与POE(6)对陈化土样中PCBs的洗脱没有协同作用;但当RL-POE(6)的浓度增加到1 505 mg/L时,RL与POE(6)对陈化土样中PCBs的洗脱具有明显的协同作用。     

载气含氧量及污染物浓度对土壤石油烃热脱附效率的影响

石油烃(TPHs)在土壤中难以降解,并具有生物毒性,异位热脱附(ESTD)在修复石油烃污染土壤方面极具应用潜力。采用实验室模拟异位热脱附装置,研究了热脱附载气含氧量及土壤石油烃污染浓度对可萃取石油烃(EPHs)中柴油段(DRO)和重油段(ORO)的5种组分去除率的影响。结果表明:在初始浓度为5 000～20 000mg·kg~(-1)时,在20 min内的脱附率均不超过50%;当初始浓度增加到40 000 mg·kg~(-1)、脱附时间为20 min时脱附率可以达到68.2%。热脱附时间为50 min时,40 000 mg·kg~(-1)污染土壤的残余浓度为407.1 mg·kg~(-1)。DOR组分相同时间的脱附率随污染浓度的升高而升高,ORO组分在50 min之内不能完全脱附,脱附率随着污染物浓度上升会出现先增大后减小的趋势。在250℃时,DRO中3个组分的去除率均随着气氛含氧量的增加而呈现明显的增长趋势。在400℃条件下,ORO中2个组分分别在含氧量为12%和15%时达到最高的去除率。本研究结果可为ESTD技术修复不同浓度的石油烃污染土壤的工程设计参数提供参考。     

生物可渗透性反应墙修复石油烃污染地下水的效果及微生物多样性研究

采用可渗透性反应墙(PRB)协同微生物作用对石油烃污染地下水进行室内模拟修复.研究结果表明,生物PRB对石油烃污染地下水具有较好的处理效果.反应器运行200 d后,生物PRB前端介质总石油烃(TPH)含量高,15个取样点的TPH质量浓度为0.74～5.42 mg/L,后端介质TPH含量较低且分布较均匀,10个取样点中TPH均低于0.29 mg/L,生物PRB出水中未检出TPH.采用聚合酶链式反应(PCR)-变性梯度凝胶电泳(DGGE)技术对生物PRB内的微生物群落结构进行分析,结果显示,生物PRB中微生物群落结构的相似性随着横向距离的增大而降低,其中B2与B5取样点微生物相似度最高,达83.1％.在生物PRB前端TPH浓度高的部位,微生物群落较为稳定,多样性较低,而后端TPH浓度低的部位,微生物群落不稳定,多样性较高.     

Chloroaromatic pollutants in mussels incubated in two finnish watercourses polluted by industry

Concentrations of different chlorinated compounds were measured in mussels incubated in two polluted watercourses, a river (the River Kymijoki) and a lake (Lake Vanaja) for four weeks in summer 1995. The sum concentrations of polychlorinated phenols (PCP) and biphenyls (PCB) were both about 1 μg/g lipid weight (lw) in Lake Vanaja mussels, while in the River Kymijoki mussels PCPs were non-detectable and PCBs were measured 120 ng/g lIw. The concentrations of toxic polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners ranged between <17 and 370 pg/g Iw in Lake Vanaja mussels and between <38 and 11,000 pg/g lw in the River Kymijoki mussels. Polychlorinated diphenyl ethers (PCDE) were detected in the mussels incubated in the River Kymijoki (0.4–1.1 ng/g Iw), but not in those incubated in Lake Vanaja. Polychlorinated phenoxyanisoles (PCPA) were measured 33 ng/g lw and polychlorinated phenoxyphenols (PCPP) 300 ng/g lw in the mussels incubated in the River Kymijoki. PCPAs were also detected in reference samples, which were sediment and pike from the River Kymijoki and Baltic salmon, seal and white-tailed sea eagle.     

Book review

The Pesticide Manual ‐ A World Compendium, 8th Edition, C.R. Worthing, Editor and S.B. Walker, Assistant Editor, British Crop Protection Council, BCPC Publications Sales, Bear Farm, Binfield, Bracknell, Berkshire RG12 5QE, England. 1987, 1100 pp., UK £50; Overseas £56. ISBN 0–948404–01–9.     

Organochlorine compounds in a three-step terrestrial food chain

The concentrations of 15 organochlorine chemicals (PCBs and pesticides) were studied in a Central European oak wood food chain system: Great tit (Parus major), caterpillars (Tortrix viridana, Operophtera brumata, Erannis defoliaria), and oak-leaves (Quercus robur). Juvenile tits receive organochlorines from the mother via egg transfer and, eventually to a greater extent, from the caterpillar food source during nestling period. The concentrations of PCB 153 (2,2′,4,4′,5,5′-hexachlorobiphenyl, the most abundant in this study) was found in leaf material at ca. 1 ng/g, in caterpillars 10 ng/g, and in bird eggs 170 ng/g on an average and on a dry mass basis.     

The chemical stability of formulations of some hydrolyzable insecticides in aqueous mixtures with hydrolysis catalysts

Abstract

The active ingredients in commercial formulations of malathion, oxamyl, carbaryl, diazinon, and chlorpyrifos diluted to “spray tank”; concentrations with buffered distilled or natural water of pH 4–9 were stable for at least 24 hr. Formulations of trichlorfon were not stable at pH 7 or above but disappearance rates were slower than for the pure chemical in homogeneous solution. Cupric ion was observed to be an effective catalyst for the hydrolysis of a variety of pure organophosphorus insecticides but did not catalyze hydrolysis of the active ingredients of the formulations examined. Increasing the dilution of the formulation increased the susceptibility of malathion, oxamyl, and carbaryl to hydrolysis.     

Radionuclides in pinon pine (Pinus edulis) nuts from los alamos national laboratory lands and the dose from consumption

Abstract

One of the dominant tree species growing within and around the eastern portion of Los Alamos National Laboratory (LANL), Los Alamos, NM, lands is the pinon pine (Pinus edulis). Pinon pine is used for firewood, fence posts, and building materials and is a source of nuts for food—the seeds are consumed by a wide variety of animals and are also gathered by people in the area and eaten raw or roasted. This study investigated the (1) concentration of ³H, ¹³⁷Cs, ⁹⁰Sr, ^totU, ²³⁸Pu, ^{239, 240}Pu, and²⁴¹ Am in soils (0‐ to 12‐in. [31 cm] depth underneath the tree), pinon pine shoots (PPS), and pinon pine nuts (PPN) collected from LANL lands and regional background (BG) locations, (2) committed effective dose equivalent (CEDE) from the ingestion of nuts, and (3) soil to PPS to PPN concentration ratios (CRs). Most radionuclides, with the exception of ³H in soils, were not significantly higher (p < 0.10) in soils, PPS, and PPN collected from LANL as compared to BG locations, and concentrations of most radionuclides in PPN from LANL have decreased over time. The maximum net CEDE (the CEDE plus two sigma minus BG) at the most conservative ingestion rate (10 lb [4.5 kg]) was 0.0018 mrem (0.018 μSv); this is far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem (1000 μSv). Soil‐to‐nut CRs for most radionuclides were within the range of default values in the literature for common fruits and vegetables.     

Degradation and sorption of imidacloprid in dissimilar surface and subsurface soils

Degradation and sorption/desorption are important processes affecting the leaching of pesticides through soil. This research characterized the degradation and sorption of imidacloprid (1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine) in Drummer (silty clay loam) and Exeter (sandy loam) surface soils and their corresponding subsurface soils using sequential extraction methods over 400 days. By the end of the incubation, approximately 55% of imidacloprid applied at a rate of 1.0 mg kg^?1 degraded in the Exeter sandy loam surface and subsurface soils, compared to 40% of applied imidacloprid within 300 days in Drummer surface and subsurface soils. At the 0.1 mg kg^?1 application rate, dissipation was slower for all four soils. Water-extractable imidacloprid in Exeter surface soil decreased from 98% of applied at day 1 to > 70% of the imidacloprid remaining after 400 d, as compared to 55% in the Drummer surface soil at day 1 and 12% at day 400. These data suggest that imidacloprid was bioavailable to degrading soil microorganisms and sorption/desorption was not the limiting factor for biodegradation. In subsurface soils > 40% of ¹⁴C-benzoic acid was mineralized over 21 days, demonstrating an active microbial community. In contrast, cumulative ¹⁴CO₂ was less than 1.5% of applied ¹⁴C-imidacloprid in all soils over 400 d. Qualitative differences in the microbial communities appear to limit the degradation of imidacloprid in the subsurface soils.     

Biochemical interaction of six op delayed neurotoxicants with several neurotargets

Abstract

Five organophosphorous insecticides: Leptophos, EPN, Cyano‐fenphos, trichloronate and salithion proved to cause irreversible ataxia not only to chicken but also to mice and sheep. TOCP was included as a reference. Cyanofenphos blocked the catecholamine B‐receptor binding activity with ³H‐norepinephrine at a level similar to that of the specific inhibitor propranolol in the mouse heart preparation. In the lamb heart preparation, the B‐receptor was more sensitive to Leptophos, salithion and TOCP than to propranolol. The six compounds and their oxons were screened for their in‐vitro inhibition to monamine oxidase (MAO), acetyl cholinesterase (AChE) and neurotoxic esterase (NTE) in the brain of either mouse, lamb or chicken. It is believed that their AChE inhibition stands for their acute toxicity, while NTE inhibition is responsible for their paralytic ataxia.     

土壤中砷的化学平衡

本文比较详细地综述了砷的化学特性,环境背景值及来源和循环,土壤中砷的三大化学平衡即沉淀溶解平衡,氧化还原平衡,吸附解吸平衡,以及微生物对砷的转化。     

Elemental uptake by edible herbs and lettuce (Latuca sativa)

The total concentration of toxic elements (aluminum, cadmium, chromium and lead) and selected macro and micro elements (iron, manganese, copper and zinc) are reported in six leafy edible vegetation species, namely lettuce, spinach, cabbage, chards and green and red types of Amaranth herbs. Although spinach and chards had greater than 125 mv of iron, both the amaranthus herbs recorded > than 320 μ g g^{? 1} dry weight. In both the spinach and chard species, the Mn and Zn levels were appreciable recording > 225 μ g g^{? 1} and 150 μ g g^{? 1} dry weight, respectively. Aluminum concentrations were (in μ g g^{? 1} dry weight) lettuce (10), cabbage (11), spinach (167), chards (65), amaranthus green (293) and amaranthus red (233). All the micro and macro elements and the toxic elements (Ni, Cr, Cd and Pb) elements analyzed, were below the recommended maximum permitted levels (RMI) in vegetables. Further the elemental uptake and distribution of the nine elements, at three growth stages of the lettuce plant grown on soil bed under controlled conditions are detailed. In the soil, except for iron (16%), greater than 33% of the other cations were in exchangeable form. Generally in the lettuce plant, roots retained much of the iron (> 224 μ g g^{? 1}) and aluminum (> 360 μ g g^{? 1}), while leaves had less than 200 μ g g^{? 1} of iron and 165 μ g g^{? 1} of Al. Although the concentrations of elements marginally decreased with growth, the lettuce leaves had significant amounts of Mn (30 μ g g^{? 1}), Zn (50 μ g g^{? 1}) and Cu (3.6 μ g g^{? 1}). Some presence of lead in leaves (2.0 μ g g^{? 1}) was noticed, but all the toxic and other elements analyzed were well below the RMI values for the vegetables.     

The dissipation of nonlyphenol in stream and pond water under simulated field conditions

Abstract

The dissipation of 1.0 ppm nonylphenol in stream and pond water, incubated in flasks at 16°C under simulated field conditions up to 44 days indicated that the half‐life was 2.5 days if the flasks were open, and 16 days if they were closed. A transformed product was detected in the closed flasks.

Translocation of nonylphenol in water occurred when treated water samples were incubated in the presence of sediment. After 10 days, nonylphenol was detected only in the sediment, but not in water (detection limit = 10 ppb). About 80% of the nonylphenol was degraded in 71 days, but no degradation occurred if the water and the sediment were autoclaved prior to incubation.