Laccase-carrying electrospun fibrous membranes for adsorption and degradation of PAHs in shoal soils

The removal of polycyclic aromatic hydrocarbons (PAHs) from soil is costly and time-consuming. The high hydrophobicity of PAHs makes PAH diffusion from soil particles by hydraulic flow difficult. The phase transfer of PAHs from soil to another available mediator is crucial for PAH removal. This study focuses on the remediation of PAH-contaminated shoal soil, located in Yangtze, China, using three types of laccase-carrying electrospun fibrous membranes (LCEFMs) fabricated via emulsion electrospinning. These LCEFMs were composed of core-shell structural nanofibers (for PAH adsorption), with laccase in the core (for PAH degradation) and pores on the shell (for mass transfer). The LCEFMs with strong adsorptivity extracted the PAHs from the soil particles, resulting in an obvious enhancement of PAH degradation. The removal efficiencies in 6 h for phenanthrene, fluoranthene, benz[a]anthracene and benzo[a]pyrene were greater than 95.1%, 93.2%, 79.1%, and 72.5%, respectively. The removal half-lives were 0.003-1.52 h, much shorter than those by free laccase (17.9-67.9 h) or membrane adsorption (1.25-12.50 h). The third-order reaction kinetics suggested that the superficial adsorption and internal diffusion were the rate-limiting steps of the overall reaction. A synergistic effect between adsorption and degradation was also proposed on the basis of the triple phase distribution and kinetics analyses.     

GC-MS测定4类食品接触材料中多环芳烃类化合物的溶出暴露水平

建立了食品接触材料中16种多环芳烃类化合物溶出暴露的气相色谱质谱联用(GC-MS)分析方法。样品以异辛烷为模拟物,按实际使用情况进行模拟浸泡实验,所得浸泡液用GC-MS进行分析。结果表明,食品接触材料中4种多环芳烃类化合物(萘、菲、荧蒽和芘)存在一定程度的溶出暴露水平,检出率分别为萘24.3%、菲77.1%、荧蒽48.6%、芘44.3%。其中部分食品用容器多环芳烃的溶出水平最高达33545 ng/kg(萘)、46296 ng/kg(菲)、17739 ng/kg(荧蒽)、15594 ng/kg(芘),并发现常规项目蒸发残渣(正己烷)的溶出与多环芳烃的溶出存在一定的正相关关系。萘、菲、荧蒽、芘等四项多环芳烃的方法平均回收率为76.5%~100.7%,相对标准偏差为1.0%~3.5%,本研究方法具有较好的准确度和精密度。     

三种光敏剂介导的光动力对水体中8种多环芳烃的降解作用

为了探究不同光敏剂(姜黄素、核黄素、金丝桃素)介导的光动力对水体中多环芳烃的降解作用,以含有8种多环芳烃的水体为研究对象,在光敏剂浓度为10μM,光照时间为15 min的条件下,采用光动力方法处理并通过同步荧光法测定水体中的各种多环芳烃.结果表明,姜黄素介导的光动力对多环芳烃的降解效果明显优于核黄素和金丝桃素介导的光动...     

Photolytic behavior of polycyclic aromatic hydrocarbons in diesel particulate matter deposited on the ground

To clarify the photolytic behavior of polycyclic aromatic hydrocarbons (PAHs) in diesel particulate matter (DPM) deposited on the ground, we determined the rate constants and half-lives for the photodegradation of benzo[a]pyrene (BaPy), phenanthrene (Phe), fluoranthene (Flrt), pyrene (Py), and chrysene (Ch) in air for three probable cases: (1) DPM is placed on an inert surface, (2) DPM is mixed with soil, and (3) PAHs are leached from DPM and adsorbed to soil. We found that BaPy and Phe degraded relatively quickly in case 1. However, in case 2, these PAHs degraded more slowly due to the effect of the presence of soil. Flrt, Py, and Ch were stable. In case 3, photodegradation of adsorbed PAHs in soil was strongly inhibited as a function of soil depth. Although these findings were obtained at extreme light intensities, they may occur under real world conditions. Conversion factors for obtaining rate constants and half-lives for PAHs on the ground under sunlight are presented. We conclude that under the average intensity of sunlight in Tokyo, photodegradation of PAHs in DPM deposited on an inert surface is very slow.     

冷冻除脂-气相色谱-串联质谱法检测食用植物油中30 种多环芳烃

建立冷冻除脂--气相色谱-串联质谱检测食用植物油中30?种多环芳烃（polycyclic aromatic hydrocarbons,PAH）的方法。选用6?种氘标记PAH为内标,样品经乙腈--丙酮溶液（4∶1,V/V）于离心管中涡旋提取,10?000?r/min离心5?min,－80?℃对油脂冷冻固化,倾出提取液,再经减压浓缩和氮气吹干,以二氯甲烷复溶,气相色谱--串联质谱多反应监测方式进行检测。结果表明,在相应质量浓度范围内30?种PAH均有良好线性（R2＞0.998）,检出限为0.10～1.83?μg/kg,定量限为0.35～6.11?μg/kg,在5、20?μg/kg和50?μg/kg添加水平下的回收率为67.77%～119.28%,相对标准偏差为1.18%～12.47%。采用本方法对市售11?类38?个食用植物油样品的检测显示,萘、1-甲基萘、2--甲基萘、联苯、2,6--二甲基萘、苊烯、苊、2,3,6--三甲基萘、芴、二苯并噻吩、菲、蒽、1-甲基菲、荧蒽、芘、环戊烯[c,d]芘、苯并[a]蒽、屈、苯并[b]荧蒽、苯并[k]荧蒽、苯并[e]芘和苯并[a]芘的检出率均为100%;5--甲基屈、苝、茚并[1,2,3--c,d]芘、二苯并[a,h]蒽、苯并[g,h,i]苝和二苯并[a,l]芘的检出率分别为86.84%、63.16%、81.58%、21.05%、81.58%和26.32%;二苯并[a,e]芘和二苯并[a,h]芘未检出;PAH总量为92.56～905.16?μg/kg,其中苯并[a]芘含量为1.94～7.40?μg/kg,依据食品安全标准限量,PAH处于较安全水平。     

Fluoranthene-2,3- and -1,5-diones are novel products from the bacterial transformation of fluoranthene

Fluoranthene is one of the predominant compounds found in soils and sediments contaminated with polycyclic aromatic hydrocarbons (PAH). Four bacterial strains isolated from PAH-contaminated soils transformed fluoranthene to a number of products during growth on phenanthrene, including the novel metabolites fluoranthene-2,3-dione (F23Q) and fluoranthene-1,5-dione (F15Q). Given the known toxicity and mutagenicity of F23Q, we focused on characterizing this metabolite with respect to its effects on the metabolism of other PAH. The yield of F23Q from fluoranthene ranged from 2% for Sphingomonas yanoikuyae R1 to greater than 20% for Pseudomonas stutzeri P16 and Bacillus cereus P21. None of the strains appeared capable of metabolizing F23Q any further. F23Q strongly inhibited phenanthrene removal by strain R1 but had a negligible to minor effect on phenanthrene degradation by the other organisms. At a concentration of 6.8 microM, F23Q also substantially inhibited the mineralization of benz[a]anthracene, benzo[a]pyrene (BaP), and chrysene by strain R1 as well as BaP mineralization by Pseudomonas saccharophila P15. Inhibition of BaP mineralization by strain P15 was still evident at an F23Q concentration of 0.68 microM. The inhibition of strain R1 by F23Q was explained in part by a cytotoxic effect, but results with strain P15 indicate that other mechanisms of inhibition occur. These findings suggest that quinones such as F23Q and F15Q have the potential to accumulate in PAH-contaminated systems and can inhibit the degradation of other PAH.     

远红外烤制对烤鱼品质及多环芳烃含量的影响

为了改善烤鱼的质构特性等食用品质,减少多环芳烃的形成,以草鱼为对象,研究传统炭烤和远红外烤制方式对烤鱼质构特性及多环芳烃含量的影响。结果表明：传统炭烤和远红外烤制对烤鱼的食用品质有不同影响,与传统炭烤鱼肉相比,远红外烤制鱼肉硬度显著降低（P＜0.05）,且剪切力均显著低于传统炭烤组（P＜0.05）,能够显著改善烤制鱼肉的嫩度;相对而言,远红外烤制鱼肉具有更优的质构特性;远红外烤制能显著降低烤鱼肉中PAH4（苯并(a)蒽、?、苯并(k)荧蒽、苯并(a)芘）和PAH16（萘、苊烯、苊、芴、菲、蒽、荧蒽、芘、苯并(a)蒽、?、苯并(b)荧蒽、苯并(k)荧蒽、苯并(a)芘、茚苯(1,2,3-c,d)芘、二苯并(a,h)蒽、苯并(g,h,i)芘）的生成量（P＜0.05）,与传统炭烤鱼肉相比,PAH4和PAH16总生成量分别下降39.07%和44.07%。     

Biostimulation of PAH degradation with plants containing high concentrations of linoleic acid

Many plant species enhance the biodegradation of polycyclic aromatic hydrocarbons (PAHs), but there is little understanding of the mechanisms by which this occurs. This research identified phytochemicals that stimulate pyrene degradation using crushed roottissues from 43 plants that were screened in soil spiked with 100 ppm pyrene. Among the plants tested, root tissues from Apium graveolens (celery), Raphanus sativus (radish), Solanum tuberosum (potato), and Daucus carota (carrot) were most effective for promoting disappearance of pyrene within 40 days. Experiments with A. graveolens showed that plant culture in soil contaminated with pyrene or benzo[a]pyrene was as effective as addition of crushed root tissues. Comparison of the chemical compositions of the effective plants suggested that linoleic acid was the major substance that stimulated PAH degradation. This hypothesis was supported in experiments examining degradation of pyrene and benzo[a]pyrene in soil amended with linoleate, whereas linolenic and palmitic acids did not stimulate degradation within a 20 day period. Antibiotic inhibitor studies implicated gram positive bacteria as a predominant group responding to linoleic acid. These findings provide insight into the mechanisms by which plants enhance degradation of PAHs, and have practical application for remediation of PAH contaminated soils.     

Removal of polycyclic aromatic hydrocarbons from contaminated soil by aqueous DNA solution

An aqueous DNA solution was applied for the extraction of polycyclic aromatic hydrocarbons (PAHs) from a spiked soil. Solubilities of 0.56, 11.78, and 11.24 mg L(-1) for anthracene, phenanthrene, and pyrene, respectively, were achieved after 1 day equilibration in 1% DNA. Using a spiked soil that contained 72 mg kg(-1) anthracene, 102 mg kg(-1) phenanthrene, and 99 mg kg(-1) pyrene, extractions of close to 88, 78, and 94%, respectively, were attained with 5% DNA at a 1:50 soil/extractant ratio. Maximum PAH dissolution occurred after 4-6 h. Comparative tests showed the main advantage of DNA over methyl-beta- and gamma-cyclodextrins and Tween 80 for pyrene removal. An ionic strength of 0.1 M NaCl was found necessary for maximum PAH dissolution and extraction. The performance of hexane regenerated DNA also remained stable after three stages of recycling. These results show the huge potential of DNA as an aqueous washing agent for PAH-contaminated soil.     

Enhancement of styrene removal efficiency in biofilter by mixed cultures of Pseudomonas sp. SR-5

The styrene-degrading bacterium Pseudomonas sp. SR-5 exhibited a high styrene removability in a biofilter. However, the styrene removal efficiency (RE) of SR-5 decreased with time. We carried out styrene gas removal in a biofilter inoculated with mixed cultures of SR-5 and other microorganisms to determine the possibility of obtaining an enhanced RE for a long period. The following three inocula were carried out: (i) styrene-degrading bacteria, strains 1 and 3, (ii) a benzoic acid-degrading bacterium Raoultella sp. A, and (iii) wastewater from a chemical company dealing with styrene. These biofilters with mixed SR-5 showed an enhanced RE compared with those with a single culture of SR-5. The complete styrene elimination capacities for ensuring 100% styrene removal in those mixed cultures were 151, 108 and 124 g/m(3)/h, compared with a single culture of SR-5.     

高风险食品中多环芳烃含量调查与分析

目的 通过对河北省11地市136份煎炸与熏烤食品中多环芳烃的（PAHs）含量的检测,考察不同食物种类、食物的来源渠道等因素对食品中PAHs含量的影响,。提示相关暴露风险。方法 样品经环己烷：乙酸乙酯(1:1, V:V)溶液超声提取后,通过凝胶色谱进行净化处理,采用高效液相色谱-荧光检测法进行检测。结果 市售的136份样品中, 均检出不同种类不同含量的PAHs, 检出率为100.0%,其中菲、蒽、荧蒽、芘及苯并(a)芘检出率较高;苯并(a)蒽、屈、苯并(b)荧蒽及苯并(k)荧蒽检出率相对较低。结论 高温、长时间反复使用的非正规散装食用油、直接使用明火煎炸与熏烤的食品中PAHs含量更高;正规厂家生产的此类食品中PAHs含量相对较低。     

Biotransformation of 8:2 fluorotelomer alcohol in soil and by soil bacteria isolates

The microbial transformation of 8:2 fluorotelomer alcohol (FTOH) to perfluorocarboxylic acids, including the globally detected perfluorooctanoic acid (PFOA), has recently been confirmed to occur in mixed bacteria cultures, activated sludge, and soil. However, little is known to date about the microbes involved in the transformation. In the present study, the effect of three carrier solvents (ethanol, octanol, and 1,4-dioxane), which may serve as carbon sources, on the aerobic degradation rate of 8:2 FTOH and metabolite distribution was evaluated both in a clay loam soil and in two pure soil bacterial cultures. Biodegradation pathways appeared similar regardless of the solvent; however, significant differences in 8:2 FTOH degradation rates were observed: 1,4-dioxane > ethanol > octanol. In the presence of 1,4-dioxane, which is not easily biodegraded, 8:2 FTOH degradation was the fastest With octanol, which is a structural analogue of 8:2 FTOH, the transformation was inhibited, but upon depletion of octanol, 8:2 FTOH was biodegraded. In the pure culture study, two soil bacterial strains, Pseudomonas species OCY4 and OCW4, enriched from soil using octanol as a sole carbon source, also transformed 8:2 FTOH without prior exposure or acclimation to 8:2 FTOH. Increased biomass resulting from octanol metabolism did increase 8:2 FTOH transformation rates; however, 8:2 FTOH could not support bacterial growth, indicating the transformation by pure cultures was via cometabolic processes.     

Polycyclic aromatic hydrocarbons in foods: human exposure through the diet in Catalonia, Spain

The dietary intake of 16 polycyclic aromatic hydrocarbons (PAHs) (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene, benzo[g,h,i]perylene, and indeno[1,2,3-c,d]pyrene) by the general population of Catalonia, Spain, was calculated. Concentrations of PAHs in food samples randomly acquired in seven cities of Catalonia from June to August 2000 were measured. Eleven food groups were included in the study. High-performance liquid chromatography was used to analyze PAHs. The dietary intakes of total and carcinogenic PAHs was calculated for five population groups: children, adolescents, male adults, female adults, and seniors. Among the analyzed PAHs, there was a predominance of phenanthrene (16.7 microg/kg) and pyrene (10.7 microg/kg). By food group, the highest levels of total PAHs were detected in cereals (14.5 microg/kg) and in meat and meat products (13.4 microg/kg). The mean estimated dietary intake of the sum of the 16 PAHs was as follows: male adults, 8.4 microg/day; adolescents, 8.2 microg/day; children, 7.4 microg/day; seniors, 6.3 microg/day; female adults, 6.3 microg/day. The calculated daily intake of PAHs would be associated with a 5/106 increase in the risk for the development of cancer in a male adult with a body weight of 70 kg.     

水产品中多环芳烃菲的检测及生物降解的研究

多环芳烃是以非极性、中性分子形式存在的一类持久性有机污染物。菲是一种含有3个苯环的多环芳烃,广泛存在于煤焦油中,能够通过生物链行为在水体和水产品中积聚。选择菲作为主要研究对象,建立了一种从水产品中高效提取菲的方法,利用高效液相色谱(HPLC)法对市售花蛤、田螺中提取的菲进行分析检测,并且利用不同浓度的菲处理后进行富集度比较。结果表明:在田螺中发现了菲的富集,其含量为56.9 ng/g;低浓度处理反而比高浓度处理富集度高。选用8种能够降解芳香环类化合物的天然菌株开展对菲降解的研究,并且对其降解条件进行初步优化。结果显示:这8种菌株均能降解菲,其中P14菌株在27 ℃条件下,震荡培养2 d,pH值为9,添加浓度为10 mg/L的钙离子,对0.1 mmol/L菲的降解效率最高。     

Soil ecotoxicity of polycyclic aromatic hydrocarbons in relation to soil sorption,lipophilicity, and water solubility

A data set was generated aiming to predict the toxicity of PAHs to soil organisms. Toxicity data include the effects of 16 PAHs on the survival and reproduction of the soil-dwelling springtail Folsomia fimetaria. The results show that only PAHs with reported log Kow values < or = 5.2 (i.e., naphthalene, acenaphthene, acenaphthylene, anthracene, phenanthrene, fluorene, pyrene, and fluoranthene) significantly affected the survival or reproduction of the test organisms. Threshold values for the toxicity of the individual PAHs could be expressed as pore-water concentrations by the use of reported organic carbon-normalized soil-pore-water partitioning coefficients (Koc values). For the PAHs with a log Kow < or = 5.2, toxicity significantly increased with increasing lipophilicity of the substances (r2 = 0.67; p = 0.012; n = 8), suggesting a narcotic mode of toxic action for most substances. However, the position of anthracene in the regression plot indicated a more specific mode of toxic action than narcosis, and removing this data point yielded the following regression equation: log EC10 (micromol/L) = -0.97 log Kow + 4.0 (r2 = 0.80; p = 0.006; n = 7). Using this quantitative structure-activity relationship (QSAR) to calculate threshold values for the toxicity of the remaining nontoxic substances (benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, dibenz[a,h]anthracene, benzo[a]pyrene, perylene, and indeno[1,2,3-cd]pyrene), the absence of toxicity could, in most cases, be explained by a limited water solubility, indicating that these substances do act by narcosis as the mode of toxic action and that their toxicity is governed by concentrations in the pore-water. The results provide important input to future model predictions of the ecological risk posed by PAH contaminated sites.     

Polycyclic aromatic hydrocarbons in mussels (Mytilus galloprovincialis) from the Ionian Sea, Italy

Concentrations of eight polycyclic aromatic hydrocarbons (PAHs) (phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, benzo[a]pyrene, dibenz[a,h]anthracene, benzo[ghi]perylene) were determined in mussels (Mytilus galloprovincialis) collected between June and September 1995 from 10 locations along a sound of sea formed by two inlets (Mar Piccolo) close to the Gulf of Taranto (Ionian Sea, Italy). In mussels the concentrations of total PAHs were between 14.8 and 645.3 microg/kg wet weight. Among the single identified compounds, the predominance of phenanthrene (29.5 microg/kg wet weight) and anthracene (64.7 microg/kg wet weight) was evident. Another relevant pollutant was pyrene (18.4 microg/kg wet weight) followed by fluoranthene (7.2 microg/kg wet weight), whereas the other compounds showed low levels. The mussels that showed the highest total concentrations of PAHs were collected from stations affected by stronger human activities (industrial fallout, urban wastewaters, and contaminants transported via riverine discharge). Our results were similar to those found in areas classified as moderately polluted. This observation suggests the need for an increased effort in controlling sources of pollution in this area recognized as one of the most productive mussel-farming areas in the Italy.     

Application of PCR-DGGE to analyse the yeast population dynamics in slurry reactors during degradation of polycyclic aromatic hydrocarbons in weathered oil

Slurry-phase reactors have been used to investigate the biodegradation feasibility of polycyclic aromatic hydrocarbons (PAHs) in weathered crude oil, by mixed culture containing five PAHs-degrading yeast strains. Yeasts were isolated from the oily soil by enrichment culture, using phenanthrene as a sole carbon source, and identified based on the 26S ribosomal DNA (rDNA) sequence. Yeast strains belonged to the genera Candida, Pichia, Rhodotorula and Sporidiobolus. The experiment was carried out for a period of 6 weeks at room temperature with a solid : liquid ratio of 50% w/w. The results showed that high removal efficiency was obtained for all PAHs, including low molecular weight (LMW) and high molecular weight (HMW) compounds (89.3-98.6% and 66.3-89.4% within 6 weeks, respectively). The higher removal efficiency for HMW-PAHs obtained in this work suggested that yeast strains mixture could play an important role to reclaim oil-contaminated sites. Denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR)-amplified 26S rRNA genes was used to follow the changes of yeast populations during the slurry reactor process. The results of DGGE indicated that Candida maltosa-like and Pichia guilliermondii were the dominant species but Rhodotorula dairenensis appeared as a weak band and Sporidiobolus salmonicolor and Pichia anomala disappeared during the study. Moreover, the results showed that all of the five strains, including the two belonging to the same genus, could be differentiated from each other in the DGGE profile.     

Degradation of 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) by brown-rot fungi

Twelve species of brown-rot fungi (BRF) have been investigated for their ability to degrade 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT). In potato dextrose broth (PDB) medium, Gloeophyllum trabeum, Fomitopsis pinicola and Daedalea dickinsii showed a high ability to degrade DDT. 1,1-Dichloro-2,2-bis (4-chlorophenyl) ethane (DDD), 1,1-dichloro-2,2-bis (4-chlorophenyl) ethylene (DDE) and 4,4-dichlorobenzophenone (DBP) were detected as metabolic products of DDT degradation by G. trabeum in PDB medium. The DDT degradation pathway in G. trabeum is proposed, which differs from the proposed pathways in bacteria and other fungi, particularly in the transformation of DDE to DDD. On the other hand, DBP was not detected as a metabolic product of DDT degradation in FeSO(4)-deficient cultures of G. trabeum, whereas DDE and DDD were detected, indicating the involvement of an iron-dependent reaction. Only DBP was detected from DDT, DDE and DDD degradation via a chemical Fenton reaction under conditions similar to those in G. trabeum cultures. These compounds may be directly transformed to DBP via a Fenton reaction.     

气相色谱-质谱法分析乳酸菌发酵苹果汁香气成分

以乳酸菌单一菌种和多菌组合分别发酵苹果汁,采用紫外-可见分光光度计测定发酵过程中苹果汁光密度(optical density,OD)的变化,采用顶空固相微萃取和气相色谱-质谱联用技术检测9组发酵苹果汁的香气成分,结合不同香气物质的阈值与香气值分析特征香气成分,并对各组苹果汁进行感官评价。结果表明:在发酵过程中苹果汁的OD值呈对数上升趋势。各组苹果汁中共鉴定出48种香气成分,主要包含醇类、酯类、醛类、酮类和酚类,其中酯类是各发酵组中种类最多且含量最大的香气类别,其次是醇类。9组苹果汁的主要香气成分和香气值较大并有突出贡献的特征香气成分均为丁酸乙酯、2-甲基丁酸乙酯、2-甲基丁基乙酸酯和乙酸己酯等。多菌发酵和单菌发酵苹果汁的香气成分含量及香气值差异显著(P0.05),说明多菌发酵中醇类、酯类和其他类香气物质的总含量明显高于单菌发酵,且赋予苹果汁更强烈的果香、青香和花香。多菌发酵组的总体感官评分高于单菌发酵组,当副干酪乳杆菌20241、动物双歧杆菌6165、嗜热链球菌6063、嗜酸乳杆菌6005活菌数比为1∶1∶1∶1时,感官评分最优。研究结果为今后乳酸菌在发酵果蔬汁方面的研究和应用提供理论依据。