一株毒死蜱降解菌的分离鉴定及降解性能研究

从农药厂废水处理池污泥中分离到一株对毒死蜱有较强降解能力的菌株CH3，通过生理生化试验初步将该菌鉴定为哈夫尼菌属(Hafnia sp.)。CH3能以毒死蜱为唯一碳源生长，在温度为30℃，pH为7.0，毒死蜱初始浓度为200 mg/L的条件下，历时6 d，毒死蜱的降解率可达78.5%。菌株最适生长温度为37℃，最适pH值为7.0，最适降解浓度为200 mg/L。对碳、氮源利用广泛，最佳碳源为蔗糖和葡萄糖，对氮源选择性不高，在无机氮源和有机氮源中均能较好地生长。     

高效阿特拉津降解菌株DNSIO降解条件优化

从长期施用阿特拉津的寒地黑土耕层（0～10cm）土壤中筛选到一株能以除草剂阿特拉津为氮源生长的降解菌株，结合16SrRNA序列分析结果，将该菌株命名为Arthrobacter sp．DNSl0。在接种量为10。CFU／mL的条件下，菌株DNSl0在24h内对100mg／L阿特拉津的降解率为99．41％。单因子实验结果表明，菌株DNSl0适宜生长和降解的条件范围是：温度25～35＇12，pH值5．0～8．0，培养液盐度0．1％～2％，对阿特拉津最大耐受浓度可达1200mg／L。正交实验法进一步表明，该菌株保持较好生长及降解能力的最优方案是温度30℃，pH值7．5，培养液盐度0．5％。影响其降解能力的环境因素的主次顺序依次是：温度〉盐度〉pH值。     

高效阿特拉津降解菌株DNS10降解条件优化

从长期施用阿特拉津的寒地黑土耕层(0～10 cm)土壤中筛选到一株能以除草剂阿特拉津为氮源生长的降解菌株,结合16S rRNA序列分析结果,将该菌株命名为Arthrobacter sp.DNS10。在接种量为108CFU/mL的条件下,菌株DNS10在24 h内对100 mg/L阿特拉津的降解率为99.41%。单因子实验结果表明,菌株DNS10适宜生长和降解的条件范围是:温度25～35℃,pH值5.0～8.0,培养液盐度0.1%～2%,对阿特拉津最大耐受浓度可达1 200 mg/L。正交实验法进一步表明,该菌株保持较好生长及降解能力的最优方案是温度30℃,pH值7.5,培养液盐度0.5%。影响其降解能力的环境因素的主次顺序依次是:温度>盐度>pH值。     

O3/H2O2降解阿特拉津影响因素研究

采用O3/H2O2氧化去除水中内分泌干扰物阿特拉津，考察了反应条件及水质对去除的影响，并对反应机制进行了初步探讨。阿特拉津初始浓度2 mg/L，投量为7.5 mg/L的O₃单独氧化去除率为27.2%；相同O₃投量下，控制H₂O₂/O₃摩尔比为0.75，5 min阿特拉津的去除率最高可达96.5%；pH 值为7.5～8.5，温度在25～40℃的范围内，都维持了较高的去除率，表明H₂O₂/O₃体系对阿特拉津的去除效果良好，降解速度快，反应条件温和。0.5 mg/L的腐殖酸，对阿特拉津的去除影响不大，腐殖酸浓度为1、2和5 mg/L时，平均去除率分别为63.4%、50.7%和30.2%；碳酸氢钠的浓度为50和200 mg/L时，去除率分别为88.1%和73.8%，说明水质对阿特拉津的去除影响较大。叔丁醇的浓度为5和20 mg/L时，阿特拉津的去除率分别降低到44.7%和27.5%，去除率随自由基抑制剂叔丁醇增加而降低，说明H₂O₂/O₃降解阿特拉津主要为该体系产生的羟基自由基的贡献。     

静态环境下阿特拉津的生物降解研究

从农药厂阿特拉津生产车间污泥中分离出菌种AT菌,进行了系列降解实验.不同温度的降解实验表明,在4～20℃的实验温度范围内,AT菌能够降解代谢污染质,并随温度的升高,降解能力增强.20℃时降解率为38.84%;AT菌在外加氮源、碳源及以阿特拉津为惟一碳源和氮源等条件时对农药污染质阿特拉津均具有降解能力,且在以阿特拉津为惟一氮源(外加碳源)条件下的降解效果最好,此时的降解率为30.39%.     

静态环境下阿特拉津的生物降解研究

从农药厂阿特拉津生产车间污泥中分离出菌种AT菌，进行了系列降解实验。不同温度的降解实验表明，在4～20℃的实验温度范围内，AT菌能够降解代谢污染质，并随温度的升高，降解能力增强。20℃时降解率为38．84％；AT菌在外加氮源、碳源及以阿特拉津为惟一碳源和氮源等条件时对农药污染质阿特拉津均具有降解能力，且在以阿特拉津为惟一氮源（外加碳源）条件下的降解效果最好，此时的降解率为30．39％。     

四环素高效降解酵母菌Trichosporon mycotoxinivoransXPY-10降解特性

Trichosporon mycotoxinivorans XPY-10是一株分离自抗生素制药厂的高效四环素降解酵母菌。为了建立该菌株降解四环素的适宜条件，分别研究了碳源、有机氮源、金属离子等营养物质及初始底物浓度、接种量、pH、温度、装液量、摇床转速等理化因素对菌体生长及四环素降解效率的影响。结果表明，菌株XPY-10生长的最适碳源和氮源分别为蔗糖和蛋白胨。在含有0.05% FeSO₄的培养基中，菌株XPY-10降解四环素的适宜条件为：接种量2%，pH 8，温度34℃，装液量100 mL（250 mL 三角瓶），摇床转速180 r/min。在此条件下，菌株XPY-10在7 d内对初始浓度为600 mg/L的四环素降解率为83.63%。本菌株对养殖废水及制药废水中四环素的污染治理有一定的应用前景。     

蒽降解菌T2的最佳培养条件及其对蒽的生物降解动力学研究

从长期被石油污染的土壤中筛选得到一株以蒽为惟一碳源的混合菌T₂，在接种量为1%，pH为7，温度为30 ℃，摇床转速为120 r/min，蒽的初始浓度为100 mg/L的条件下培养5 d后，其对蒽的降解率可以达到56.6%。通过单因素实验和正交实验对菌种T₂的培养条件进行研究，得到菌种T₂的最佳培养条件为：接种量为5%，pH为6，温度为35 ℃，蒽的初始浓度为40 mg/L时，最适合菌种生长。另外，菌种T₂对蒽的降解动力     

嗜盐菌的筛选及原油降解性能简

油气开发过程含油废液中过高的盐含量是影响其生物处理效果不佳的一个重要因素。针对含油废液的特点，实验从油田废弃泥浆中筛选分离出一株高效嗜盐降解菌，该菌呈杆状，经BIOLOG鉴定系统与分子序列鉴定分析，该菌为芽孢杆菌Bacillus subtilis strain；研究了嗜盐菌的耐盐碱性及原油降解性能，结果表明，该菌适宜于碱性环境，适盐浓度范围为5 000~200 000 mg/L，7 d内对高盐含油模拟废水中原油的降解率高达60%，最佳降解条件为：菌液/培养液体积比1：12.5，pH=9，NaCl浓度范围为10 000~50 000 mg/L，最佳N源和P源分别为（NH₂）₂CO和K₂HPO₄·3H₂O。嗜盐菌的研究为高盐含油废液的生物处理拓展了一条新的技术途径。     

固定化混合菌修复油污染地表水的研究

从辽河油田受石油污染的河床底泥中筛选出一株芽孢杆菌(Bacillus sp.)和一株黄杆菌(Flavobacterium sp.)，采用二次交联化学方法对2株细菌单独及混合固定，分别进行了不同接种量的固定化细菌对油的降解，以及固定化混合菌对环境的耐受性和在自然地表水中对油的降解进行研究，结果表明，在相同时间内固定化混合菌对油的降解效果明显优于固定化单株菌，而且都优于游离菌。固定化混合菌pH在6～10、温度在20～40℃范围内能保持较好的活性。在120 h时，固定化混合菌对自然地表水中油的降解率达94.5%,对地表水中COD的去除率达89.6%。扫描电子显微镜分析显示，固定化载体的微观结构适合细菌的生长，固定化混合菌在载体内部形成高密度的菌群。以上的研究为固定化微生物应用于油污染地表水的生物修复提供了一定的理论基础。     

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.     

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.     

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.     

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.     

Levels of PCDDs and PCDFs in products and effluent from the Swedish pulp and paper industry and chloralkali process

Within the Swedish Dioxin Survey various samples from the pulp and paper industry and the chloralkali process have been analyzed by congener specific analytical methods. In addition to the generally discussed “bleaching pattern” of the tetrachlorinated congeners, these samples also contained higher chlorinated congeners like hexa-CDDs, hepta-CDFs, octa-CDD and octa-CDF. Consequently it is recommended that samples from the pulp industry should be analyzed for all PCDDs and PCDFs (tetra- through octa-). Counted as Nordic Toxic Equivalents (NTEQ), the recycled pulp samples had the highest contamination level followed by TMP, unbleached sulfite and bleached softwood and hardwood. In addition to the bleaching process, various chemicals used in the pulping, bleaching and wastewater treatment can contribute to the contamination.     

Field and laboratory studies of the fate and enantiomeric enrichment of venlafaxine and O-desmethylvenlafaxine under aerobic and anaerobic conditions

The stereoselectivity of R,S-venlafaxine and its metabolites R,S-O-desmethylvenlafaxine, N-desmethylvenlafaxine, O,N-didesmethylvenlafaxine, N,N-didesmethylvenlafaxine and tridesmethylvenlafaxine was studied in three processes: (i) anaerobic and aerobic laboratory scale tests; (ii) six wastewater treatment plants (WWTPs) operating under different conditions; and (iii) a variety of wastewater treatments including conventional activated sludge, natural attenuation along a receiving river stream and storage in operational and seasonal reservoirs. In the laboratory and field studies, the degradation of the venlafaxine yielded O-desmethylvenalfaxine as the dominant metabolite under aerobic and anaerobic conditions. Venlafaxine was almost exclusively converted to O-desmethylvenlafaxine under anaerobic conditions, but only a fraction of the drug was transformed to O-desmethylvenlafaxine under aerobic conditions. Degradation of venlafaxine involved only small stereoisomeric selectivity. In contrast, the degradation of O-desmethylvenlafaxine yielded remarkable S to R enrichment under aerobic conditions but none under anaerobic conditions. Determination of venlafaxine and its metabolites in the WWTPs agreed well with the stereoselectivity observed in the laboratory studies. Our results suggest that the levels of the drug and its metabolites and the stereoisomeric enrichment of the metabolite and its parent drug can be used for source tracking and for discrimination between domestic and nondomestic wastewater pollution. This was indeed demonstrated in the investigations carried out at the Jerusalem WWTP.     

Uptake and translocation of metformin, ciprofloxacin and narasin in forage- and crop plants

Transfer of bioactive organic compounds from soil to plants might represent animal and human health risks. Sewage sludge and manure are potential sources for bioactive compounds such as human- and veterinary drugs. In the present study, uptake of the anti-diabetic compound, metformin, the antibiotic agent ciprofloxacin and the anti-coccidial narasin in carrot (Daucuscarota ssp. sativus cvs. Napoli) and barley (Hordeumvulgare) were investigated. The pharmaceuticals were selected in order to cover various chemical properties, in addition to their presence in relevant environmental matrixes. The root concentration factors (RCF) found in the present study were higher than the corresponding leaf concentration factors (LCF) for the three test pharmaceuticals. The uptake of metformin was higher compared with ciprofloxacin and narasin for all plant compartments analyzed. Metformin was studied more explicitly with regard to uptake and translocation in meadow fescue (Festucapratense), three other carrot cultivars (D.carota ssp. sativus cvs. Amager, Rothild and Nutri Red), wheat cereal (Triticumaestivum) and turnip rape seed (Brassicacampestris). Uptake of metformin in meadow fescue was comparable with uptake in the four carrot cultivars (RCF 2-10, LCF approximately 1.5), uptake in wheat cereals were comparable with barley cereals (seed concentration factors, SCF, 0.02-0.04) while the accumulation in turnip rape seeds was as high as 1.5. All three pharmaceuticals produced negative effects on growth and development of carrots when grown in soil concentration of 6-10 mg kg⁻¹ dry weight.     

Copper-catalyzed chlorination and condensation of acetylene and dichloroacetylene

The chlorination and condensation of acetylene at low temperatures is demonstrated using copper chlorides as chlorinated agents coated to model borosilicate surfaces. Experiments with and without both a chlorine source and borosilicate surfaces indicate the absence of gas-phase and gas-surface reactions. Chlorination and condensation occur only in the presence of the copper catalyst. C₂ through C₈ organic products were observed in the effluent; PCDD/F were only observed from extraction of the borosilicate surfaces. A global reaction model is proposed that is consistent with the observed product distributions. Similar experiments with dichloroacetylene indicate greater reactivity in the absence of the copper catalyst. Reaction is observed in the gas-phase and in the presence of borosilicate surfaces at low temperatures. The formation of hexachlorobenzene is only observed in the presence of a copper catalyst. PCDD/F were only observed from extraction of the borosilicate surfaces. A global reaction model is proposed for the formation of hexachlorobenzene from dichloroacetylene.     

Aerobic and anaerobic degradation of profluralin and trifluralin

Abstract

The degradation of profluralin [N‐(cyclopropylmethyl)‐α,α,α‐trifluoro‐2,6‐dinitro‐N‐propyl‐]p‐toluidine] and trifluralin (α,α,α‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) was studied under aerobic and anaerobic soil conditions. Three soils (Goldsboro loamy sand, Cecil loamy sand, Drummer clay loam) were each treated with 1 ppmw herbicide; anaerobic conditions were maintained by flooding. Soil samples were extracted monthly and subjected to TLC analysis. No degradation was detected in sterile controls. Aerobic degradation of both herbicides was greatest in the Cecil loamy sand soil over the entire incubation period. Degradation of profluralin in Cecil soil under aerobic conditions was 86 percent after 4 months with three products detected; 83 percent of the trifluralin was degraded with two products detected. Anaerobic degradation accounted for 72 percent of the profluralin and 78 percent of the trifluralin after 4 months. Degradation of both herbicides increased with incubation time for the first 3 months and decreased slightly thereafter. Generally there was more extensive degradation (percent and in number of products formed) of profluralin than trifluralin under the conditions tested. More degradation products were detected for both herbicides under aerobic conditions than under anaerobic conditions.     

Sources and distribution of polychlorinated-dibenzo-p-dioxins and -dibenzofurans in soil and sediment from the Yellow Sea region of China and Korea

Polychlorinated-dibenzo-p-dioxins and -dibenzofurans (PCDD/Fs) were measured in soils and sediments from the Yellow Sea region. Korean soils and sediments mostly contained detectable PCDD/Fs and showed a widespread distribution among locations. Soil and sedimentary PCDD/Fs from China were comparable to or less than those in Korea. The patterns of relative concentrations of individual congeners in soils were different between the two countries, but similar in sediments. Sources of PCDD/Fs in China and Korea were found to be independent of each other and their distributions reflected matrix-dependent accumulation. Spatial distribution indicated some point sources in Korea while Chinese sources were more widespread and diffuse. PCDD/Fs measured in the coastal areas of the Yellow Sea were comparable to or less than those previously reported in for eastern Asia. However, ∑TEQs in soils and sediments were near to or, in some cases exceeded environmental quality guidelines.