抗铬菌株的筛选鉴定及其生物学特性和吸附特性

利用微生物分离纯化技术,在培养基中加入不同浓度的Cr3+、Cr6+,经过长时间驯化,从污染土壤中筛选出2株对Cr具有较高抗性的菌株(A和B),对其进行了形态、生理生化特性及分子生物学鉴定,并研究了其最佳生长条件及对Cr3+的生物吸附规律。结果表明,菌株A和B分别为蜡状芽孢杆菌(Bacillus cereus)和米根霉菌(Rhizopus oryzae)。菌株A和B的最适生长pH值均为7,最适生长温度均为30℃,最佳装液量为80~100 mL(250 mL摇瓶)。在培养时间一定时,随着Cr3+浓度的增加,菌株对Cr3+的吸附率减少,而生物吸附量则逐渐增大;在Cr3+浓度一定时,随着培养时间的延长,菌体对Cr3+的吸附率呈现出先增加后减少的趋势,这与生物吸附量的变化趋势基本一致。在Cr3+浓度为100 mg/L时,菌株A和B对Cr3+的吸附率达到最大,分别为51.47%和46.36%。     

不同基质条件下厌氧氨氧化反应器中硝化细菌的分离及选育异养AOB菌株的特性

对长期分别以模拟配水和生活污水为基质运行的ASBR厌氧氨氧化反应器中的硝化细菌进行解析,对比了2种基质条件下厌氧氨氧化反应器中硝化细菌的群落结构,并分别选育的异养AOB菌株a-2-2和YA-2-4L的生长和脱氮特性进行研究。实验结果表明,以生活污水为基质的反应器比模拟配水为基质的反应器中硝化细菌的生态多样性更丰富。在生活污水为基质的反应系统中挑选的a-2-2菌株为假单胞菌属,其48 h内NH+4从39 mg/L下降到5.83 mg/L,NH+4去除率为85.06%,其最适生长pH为7.5,而在pH为8时具有最佳的硝化能力,在盐度为0%~4%范围内活性较好,其最适生长温度36℃,但在32℃具有最佳的硝化能力;在以模拟配水为基质的反应系统中挑选的YA-2-4L菌株为不动杆菌属,其48h内NH+4从39.1 mg/L下降到6.95 mg/L,NH+4去除率为82.22%,最适生长pH为7.5,而在pH为8时具有最佳的硝化能力,在盐度为0%~4%范围内活性较好,其最适生长温度为36℃,但在32℃具有最佳的硝化能力。     

氢氧化镁处理含镍废水的研究

考察了氢氧化镁用量、搅拌时间、温度及pH对处理效果的影响 ,初步探讨了吸附作用机理。结果表明 :氢氧化镁对镍离子具有较强的吸附性能 ,去除率可达 99%以上。吸附等温线符合Langmuir模式 ,饱和吸附量 17.5 7mg/g。含Cd2 +、Ni2 +和Pb2 +的电镀废水经氢氧化镁吸附后 ,出水达到国家排放标准。     

4A沸石去除水中Pb~(2+)的研究

在静态条件下,研究了4A沸石对废水中Pb2+的吸附性能,并探讨了影响吸附的因素。实验表明:当温度为30℃,废水pH为5~6,0.01 g4A沸石对100 mg/LPb2+溶液10 mL吸附20 min,Pb2+的去除率可达到99%以上。在实验研究条件下,4A沸石对Pb2+的吸附符合Langmuir和Freundlich等温吸附方程,相关系数为0.9819和0.9998。经计算,4A沸石对Pb2+的饱和吸附量为125 mg/g。4A沸石吸附水中Pb2+,达到吸附平衡的时间较短;溶液pH值的变化对吸附效果影响不显著;温度从室温略微升高,Pb2+的去除率略有增大。吸附在4 A沸石上的Pb2+可回收利用,处理后的4A沸石可以再生,且重复使用性能较好。     

4A沸石对复合污染水体中Pb2+、Cu2+和Cd2+的去除

采用静态吸附法以4A沸石为吸附剂研究其对复合污染水体中Pb2+、Cu2+和Cd2+的竞争吸附特性,并探讨了影响吸附的环境因素。实验表明,在室温条件下,溶液pH5～6,4A沸石15 mg对10 mL复合污染溶液(Pb2+、Cu2+和Cd2+浓度分别为100 mg/L)吸附20 min时,对溶液中3种重金属的吸附去除率均可达99.8%以上。反应过程中4A沸石对3种重金属的吸附速率大小为Pb2+>Cu2+>Cd2+。复合污染水体中4A沸石对Pb2+、Cu2+和Cd2+的吸附符合Langmuir和Fre-undlich等温吸附方程,相关系数分别为0.9981、0.9901、0.9916和0.9638、0.9194、0.9689。经计算,4A沸石对Pb2+、Cu2+和Cd2+的饱和吸附量分别为129.9 mg/g、107.5 mg/g和99.0 mg/g。4A沸石吸附重金属离子达到吸附平衡的时间较短,对溶液pH值的适应性较好。吸附后的4A沸石可以再生利用,对铅离子洗脱重复利用性较铜离子和镉离子强。     

一株脱氨除臭菌的分离鉴定及在鸡粪中的脱氮特性

为脱除鸡粪中的臭味,从黑土中分离并鉴定了一株脱氨除臭菌株并研究其特性.通过生理生化特性及16S rDNA序列分析对分离到的菌株进行鉴定,并研究了菌株的生长特性以及硝化与异养硝化能力.结果表明,菌株QDTN-34属于霍氏肠杆菌属(Enterobacter hormaechei),QDTN-34菌株的最适生长温度在27℃左右,最适生长pH为8,生长最佳C/N为25∶1;QDTN-34菌株在培养基内培养3d时,对氨氮的去除率高达到64.75％,对硝氮的去除率高达到71.00％.在鸡粪除臭过程中,在C/N为25∶1的鸡粪中最佳接种量为5.0％,在鸡粪中培养9d时,菌数可达到(2.5 ～2.6)×108cfu/mL,其对氨氮和硝氮的去除率分别达到59.90％和67.71％.总之,QDTN-34菌株的生物特性稳定,环境的适应能力强,脱氨除臭能力佳,具有良好的应用前景.     

一株反硝化细菌的分离鉴定及其反硝化特性

从处理城镇污水的移动床生物膜反应器中分离获得一株反硝化细菌D3,并进一步研究该菌株的系统发育地位及反硝化特性。采用16S rDNA序列分析对菌株进行初步鉴定,探讨了基质浓度、起始pH和温度对菌株反硝化活性的影响。根据形态学特征、生理生化特性及16S rDNA序列测定分析,初步鉴定菌株属于寡养单胞菌属。该菌能利用硝酸钠或亚硝酸钠进行反硝化作用,最佳电子受体是硝酸盐氮,反硝化速率最大为19.86 mg/(L·h),最适生长pH为7.36,最适生长温度为33.5℃。菌株D3在初始硝态氮浓度为140 mg/L,以乙酸钠为惟一碳源,pH为7.36,温度33.5℃的最优生长条件下,培养10 h进入对数生长期,倍增时间为9.9 h,48 h内硝酸盐还原率达95%。     

新型TCAS吸附树脂对水中Cd~(2+)的吸附去除研究

通过静态吸附试验,研究一种由超分子受体化合物磺化硫杂杯芳烃(TCAS)与树脂结合的产物--新型TCAS吸附树脂对重金属Cd2+的吸附去除性能,并初步探讨了吸附机理.试验研究结果表明,TCAS吸附树脂对Cd2+的饱和吸附量为14.45 mg/g.当温度为20℃,0.5 g TCAS吸附树脂对10 mL浓度为5 mg/L的Cd2+溶液吸附60 min时,Cd2+的去除率可达到99%以上.pH值是影响TCAS吸附树脂吸附效果的重要因素,在pH=5～9时,Cd2+的去除率随着pH值的升高而增大.在试验范围内,TCAS吸附树脂对Cd2+吸附符合Freundlich方程.吸附在TCAS吸附树脂上的Cd2+可洗脱回收,TCAS吸附树脂也可再生利用.TCAS吸附树脂对重金属Cd2+的吸附机理主要归因于TCAS对Cd2+的络合作用.     

Cd~(2+)和Pb~(2+)对四环素超声降解性能的影响

通过紫外分光光度法,研究了Cd2+和Pb2+对四环素超声降解过程的影响。研究结果表明,Cd2+和Pb2+在水中与四环素发生络合反应后,在紫外光谱上发生蓝移,在206 nm处产生新的峰值。同时,在低摩尔比(四环素∶重金属1)时,Cd2+和Pb2+可以加快四环素的超声降解。0.01 mmol/L四环素溶液24 h的超声降解率为7.54%,加入Pb2+和Cd2+离子后,四环素去除率分别升高至20.82%和18.75%。在高摩尔比(四环素∶重金属2)时,Cd2+和Pb2+抑制了四环素的降解,在0.08 mmol/L四环素溶液中,加入Pb2+和Cd2+离子反而使四环素去除率从4.69%分别降低至2.04%和1.40%。     

污泥中嗜酸酵母菌的分离鉴定及其重金属耐受性研究

从污水处理厂的活性污泥中分离纯化出一株嗜酸异养菌,命名为JJU-2,并对其进行了形态观察、生理生化特性测试及26SrDNA的D1/D2区序列分析,鉴定该菌株为假丝酵母菌(Candida palmioleophila)。进一步对JJU-2菌株的生长特性和重金属耐受性进行研究。结果表明:该菌株最适生长pH为3~6,且能适应pH3的极端酸性环境,最适生长温度为25℃,最高耐受温度为40℃,当培养至3h,JJU-2菌株进入对数生长期,培养至18h进入稳定期。Cr~(3+)、Ni~(2+)、Pb~(2+)对JJU-2菌株的最低抑菌摩尔浓度分别为20、2.0、40mmol/L。     

Sorption and desorption of Cu and Cd by macroalgae and microalgae

The sorption and desorption of Cu and Cd by two species of brown macroalgae and five species of microalgae were studied. The two brown macroalgae, Laminaria japonica and Sargassum kjellmanianum, were found to have high capacities at pHs between 4.0 and 5.0 while for microalgae, optimum pH lay at 6.7. The presence of other cations in solution was found to reduce the sorption of the target cation, suggesting a competition for sorption sites on organisms. Sorption isotherms obeyed the Freundlich equation, suggesting involvement of a multiplicity of mechanisms and sorption sites. For the microalgae tested, Spirulina platensis had the highest capacity for Cd, followed by Nannochloropsis oculata, Phaeodactylum tricornutum, Platymonas cordifolia and Chaetoceros minutissimus. The reversibility of metal sorption by macroalgae was examined and the results show that both HCl and EDTA solutions were very effective in desorbing sorbed metal ions from macroalgae, with up to 99.5% of metals being recovered. The regenerated biomass showed undiminished sorption performance for the two metals studied, suggesting the potential of such material for use in water and wastewater treatment.     

Dioxin- and POP-contaminated sites—contemporary and future relevance and challenges

BACKGROUND, AIM AND SCOPE: Once they have been generated, polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and other persistent organic pollutants (POPs) can persist in soils and sediments and in waste repositories for periods extending from decades to centuries. In 1994, the US EPA concluded that contaminated sites and other reservoirs are likely to become the major source of contemporary pollution problems with these substances. With this in mind, this article is the first in a new series in ESPR under the title 'Case Studies on Dioxin and POP Contaminated Sites--Contemporary and Future Relevance and Challenges', which will address this important issue. The series will document various experiences from sites contaminated with PCDD/F and other POPs. This article provides an overview of the content of the articles comprising the series. In addition, it provides a review of the subject in its own right and identifies the key issues arising from dioxin/POP-contaminated sites. Additionally, it highlights the important conclusions that can be drawn from these examples. The key aim of this article and of the series as a whole is to provide a comprehensive overview of the types of PCDD/F contaminated sites that exist as a result of historical activities. It details the various processes whereby these sites became contaminated and attempts to evaluate their contemporary relevance as sources of PCDD/Fs and other POPs. It also details the various strategies used to assess these historical legacies of contamination and the concepts developed, or which are under development, to effect their remediation. MAIN FEATURES: Special sessions on 'Contaminated sites--Cases, remediation, risk and policy' were held at the DIOXIN conferences in 2006 and 2007, and this theme will be continued at DIOXIN 2008 to be held in Birmingham. Selected cases from the approximately 70 contributions made to these sessions, together with some additional invited case studies are outlined together with the key issues they raise. By evaluating these cases and adding details of experiences published in the current literature, an overview will be given of the different features and challenges of dioxin and POP-contaminated sites. RESULTS: This article provides a systematic categorisation of types of PCDD/F and POP-contaminated sites. These are categorised according to the chemical or manufacturing process, which generated the PCDD/Fs or POPs and also includes the use and disposal aspects of the product life cycle in question. The highest historical PCDD/F and dioxin-like polychlorinated biphenyl (PCB) contamination burdens have arisen as a result of the production of chlorine and of chlorinated organic chemicals. In particular, the production of chlorinated pesticides, PCBs and the related contaminated waste streams are identified being responsible for historical releases of toxic equivalents (TEQs) at a scale of many tonnes. Along with such releases, major PCDD/F contaminated sites have been created through the application or improper disposal of contaminated pesticides, PCBs and other organochlorine chemicals, as well through the recycling of wastes and their attempted destruction. In some extreme examples, PCDD/F contaminated sites have also resulted from thermal processes such as waste incinerators, secondary metal industries or from the recycling or deposition of specific waste (e.g. electronic waste or car shredder wastes), which often contain chlorinated or brominated organic chemicals. The examples of PCDD/F and dioxin-like PCB contamination of fish in European rivers or the impact of contaminated sites upon fishing grounds and upon other food resources demonstrate the relevance of these historical problems to current and future human generations. Many of the recent food contamination problems that have emerged in Europe and elsewhere demonstrate how PCDD/F and dioxin like PCBs from historical sources can directly contaminate human and animal feedstuffs and indeed highlight their considerable contemporary relevance in this respect. Accordingly, some key experiences and lessons learnt regarding the production, use, disposal and remediation of POPs from the contaminated sites are summarised. DISCUSSION: An important criterion for evaluating the significance and risks of PCDD/Fs and other POPs at contaminated sites is their present or future potential for mobility. This, in turn, determines to a large degree their propensity for off-site transport and environmental accessibility. The detailed evaluation of contaminated site cases reveals different site-specific factors, which influence the varied pathways through which poor water-soluble POPs can be mobilised. Co-contaminants with greater water solubility are also typically present at such sites. Hence, pumping of groundwater (pump and treat) is often required in addition to attempting to physically secure a site. At an increasing number of contaminated sites, securing measures are failing after relatively short time spans compared to the time horizon, which applies to persistent organic pollutant contamination. Due to the immense costs and challenges associated with remediation of contaminated sites 'monitored natural attenuation' is increasingly gaining purchase as a conceptual remediation approach. However, these concepts may well prove limited in their practical application to contaminated sites containing persistent organic pollutants and other key pollutants like heavy metals. CONCLUSIONS: It is inevitable, therefore, that dioxin/POP-contaminated sites will remain of contemporary and future relevance. They will continue to represent an environmental issue for future generations to address. The securing and/or remediation of dioxin/POP-contaminated sites is very costly, generally in the order of tens or hundreds of millions of dollars. Secured landfills and secured production sites need to be considered as constructions not made for 'eternity' but built for a finite time scale. Accordingly, they will need to be controlled, supervised and potentially repaired/renewed. Furthermore, the leachates and groundwater impacted by these sites will require ongoing monitoring and potential further remediation. These activities result in high maintenance costs, which are accrued for decades or centuries and should, therefore, be compared to the fully sustainable option of complete remediation. The contaminated site case studies highlight that, while extensive policies and established funds for remediation exist in most of the industrialised western countries, even these relatively well-regulated and wealthy countries face significant challenges in the implementation of a remediation strategy. This highlights the fact that ultimately only the prevention of contaminated sites represents a sustainable solution for the future and that the Polluter Pays Principle needs to be applied in a comprehensive way to current problems and those which may emerge in the future. RECOMMENDATIONS AND PERSPECTIVES: With the continuing shift of industrial activities in developing and transition economies, which often have poor regulation (and weak self-regulation of industries), additional global challenges regarding POPs and other contaminated sites may be expected. In this respect, a comprehensive application of the "polluter pays principle" in these countries will also be a key to facilitate the clean-up of contaminated areas and the prevention of future contaminated sites. The threats and challenges of contaminated sites and the high costs of securing/remediating the problems highlight the need for a comprehensive approach based upon integrated pollution prevention and control. If applied to all polluting (and potentially polluting) industrial sectors around the globe, such an approach will prove to be both the cheapest and most sustainable way to underpin the development of industries in developing and transition economies.     

Persistence and dissipation kinetics of trifloxystrobin and tebuconazole in onion and soil

The persistence and dissipation kinetics of trifloxystrobin and tebuconazole on onion were studied after application of their combination formulation at a standard and double dose of 75 + 150 and 150 + 300 g a.i. ha^?1. The fungicides were extracted with acetone, cleaned-up using activated charcoal (trifloxystrobin) and neutral alumina (tebuconazole). Analysis was carried out by gas chromatograph (GC) and confirmed by gas chromatograph mass spectrometry (GC-MS). The recovery was above 80% and limit of quantification (LOQ) 0.05 mg kg^?1 for both fungicides. Initial residue deposits of trifloxystrobin were 0.68 and 1.01 mg kg^?1 and tebuconazole 0.673 and 1.95 mg kg^?1 from standard and double dose treatments, respectively. Dissipation of the fungicides followed first-order kinetics and the half life of degradation was 6–6.6 days. Matured onion bulb (and field soil) harvested after 30 days was free from fungicide residues. These findings suggest recommended safe pre-harvest interval (PHI) of 14 and 25 days for spring onion consumption after treatment of Nativo 75 WG at the standard and double doses, respectively. Matured onion bulbs at harvest were free from fungicide residues.     

Kinetic and structural relationships of transition monomeric and oligomeric carboxyl- and choline-esterases

The kinetic and structural relationships of eight electrophoretically pure mammalian serum and liver serine carboxylesterases (CE) and cholinesterases (ChE) have been studied. Eight CE's and ChE's, which were fully resolved but only partially purified, provided additional information. Five of the electrophoretically pure esterases were monomeric, and of these, four belonged to a new and widely distributed class. These four monomeric esterases hydrolyzed choline esters, but at widely differing rates. Thus two were termed monomeric butyrylcholinesterases, mBuChE I and II, and two were monomeric CE's (mCE). The rabbit liver mCE was not a subunit of the oligomeric CE (oCE), although the oCE also hydrolyzed choline esters at a very low rate. The complex kinetics of the mCE's, mBuChE's, oCE's, and of the oligomeric BuChE's of horse and human serum could be interpreted according to a single reaction scheme involving an allosteric site and the equation derived from it. Thus activation and inhibition at high substrate concentrations, together with sigmoidal activity versus substrate concentration plots, all of which characterize the reactions of these esterases, could be interpreted by a single scheme and equation. Structural and kinetic comparisons showed a progressive transition of properties from the oCE's through the mCE's to the oBuChE's. One of the purified mCE's was from horse serum, and it exhibited physical and kinetic properties unlike those of the liver mCE's or oCE's.     

Sorption and Desorption Behavior of Chloroanilines and Chlorophenols on Montmorillonite and Kaolinite

The bioavailability of pollutants, pesticides and/or their degradation products in soil depends on the strength of their sorption by the different soil components, particularly by the clay minerals. This study reports the sorption-desorption behavior of the environmentally hazardous industrial pollutants and certain pesticides degradation products, 3-chloroaniline, 3,4-dichloroaniline, 2,4,6-trichloroaniline, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol on the reference clays kaolinite KGa-1 and Na-montmorillonite SWy-l. In batch studies, 2.0 g of clay were equilibrated with 100.0 mL solutions of each chemical at concentrations ranging from 10.0 to 200.0 mg/L. The uptake of the compounds was deduced from the results of HPLC-UV-Vis analysis. The lipophilic species were best retained by both clay materials. The most lipophilic chemical used in the study, 2,4,6-trichloroaniline, was also the most strongly retained, with sorption of up to 8 mg/g. In desorption experiments, which also relied on HPLC-UV-Vis technique, 2,4,6-trichloroaniline was the least desorbed from montmorillonite. However, on kaolinite all of the compounds under study were irreversibly retained. The experimental data have been modelled according to the Langmuir and Freundlich isotherms. A hypothesis is proposed concerning the sorption mechanism and potential applications of the findings in remediation strategies have been suggested.     

Sorption and desorption behavior of chloroanilines and chlorophenols on montmorillonite and kaolinite

The bioavailability of pollutants, pesticides and/or their degradation products in soil depends on the strength of their sorption by the different soil components, particularly by the clay minerals. This study reports the sorption-desorption behavior of the environmentally hazardous industrial pollutants and certain pesticides degradation products, 3-chloroaniline, 3,4-dichloroaniline, 2,4,6-trichloroaniline, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol on the reference clays kaolinite KGa-1 and Na-montmorillonite SWy-l. In batch studies, 2.0 g of clay were equilibrated with 100.0 mL solutions of each chemical at concentrations ranging from 10.0 to 200.0 mg/L. The uptake of the compounds was deduced from the results of HPLC-UV-Vis analysis. The lipophilic species were best retained by both clay materials. The most lipophilic chemical used in the study, 2,4,6-trichloroaniline, was also the most strongly retained, with sorption of up to 8 mg/g. In desorption experiments, which also relied on HPLC-UV-Vis technique, 2,4,6-trichloroaniline was the least desorbed from montmorillonite. However, on kaolinite all of the compounds under study were irreversibly retained. The experimental data have been modelled according to the Langmuir and Freundlich isotherms. A hypothesis is proposed concerning the sorption mechanism and potential applications of the findings in remediation strategies have been suggested.     

Bacterial and archaeal diversity in oil fields and reservoirs and their potential role in hydrocarbon recovery and bioprospecting

Environmental Science and Pollution Research - Hydrocarbon is a primary source of energy in the current urbanized society. Considering the increasing demand, worldwide oil productions are declining...     

畜禽养殖业污染与循环经济

解决畜禽养殖业的污染问题要以充分利用资源为根本出发点，通过对污染全过程控制及废物综合利用，达到畜禽粪便的减量化、无害化、资源化，走循环经济的发展道路。     

Synthesis and characterization of m- and p-methylbenzyl-mercapturic acids derived from m- and p-xylenes

Chemical synthesis and physical properties of two mercapturic acids suggested as urinary metabolites of m- and p-xylenes ace described. These compounds may be used for the identification and quantivative determination by high-performance liquid chromatography of the corresponding mercapturic acids in urine.