Characterization of the extracellular biodemulsifiers secreted by Bacillus cereus LH-6 and the enhancement of demulsifying efficiency by optimizing the cultivation conditions

A highly efficient demulsifying strain, LH-6, was isolated from petroleum-contaminated soil and identified as Bacillus cereus by 16S rDNA gene analysis. It achieved 95.61 and 95.40 % demulsifying ratios within 12 h for water-in-oil (W/O) and oil-in-water (O/W) model emulsions, respectively. Fourier transform infrared spectroscopy (FT-IR) and thin-layer chromatography (TLC) detections indicated that the LH-6’s extracellular biodemulsifiers were different types of lipopeptides for the W/O and O/W emulsions. Optimization of the culture medium composition was conducted to improve the biosynthesis and demulsifying efficiency of the biodemulsifier. The optimal carbon source was liquid paraffin, while waste frying oil could also be an alternative carbon source. The optimal nitrogen sources were ammonium sulfate and yeast extract. To further enhance the biodemulsifier efficiency, the optimal cultivation conditions were determined using response surface methodology (RSM) based on central composite rotation design (CCRD). Using the optimized cultivation conditions, the demulsifying ratios increased to 98.23 and 97.65 % for the W/O and O/W model emulsions, respectively.     

循环流化床锅炉燃煤技术热电厂生命周期评价

运用生命周期评价方法,应用Gabi5.0软件对采用循环流化床锅炉燃煤技术的热电企业进行资源耗竭和环境影响分析,计算各生产单元生命周期清单的全球变暖潜值、酸化效应潜值、富营养化潜值、非生物资源耗竭潜值、人体毒性潜值以及光化学烟雾和臭氧生成潜值等主要环境影响类型,对燃煤发电过程进行生命周期评价。结果表明,全球变暖和非生物资源耗竭为发电运行过程中主要的环境影响因素,分别占53%和15.05%;锅炉燃烧阶段的环境影响最重,占整个生命周期影响值的77.12%,并且除生物耗竭潜值外的其他5项指标均为发电运行阶段各个单元中最高。采用SNCR脱硝技术减少燃烧过程中NOx的排放量,并对该技术方案进行生命周期评价,比较方案实施前后的环境影响。     

Carbamazepine, carbamazepine epoxide and dihydroxycarbamazepine sorption to soil and occurrence in a wastewater reuse site in Tunisia

Although a number of manufactured nanoparticles are applied for the medical and clinical purposes, the understanding of interaction between nanomaterials and biological systems are still insufficient. Using nematode Caenorhabditis elegans model organism, we here investigated the in vivo toxicity or safety of hydroxylated fullerene nanoparticles known to detoxify anti-cancer drug-induced oxidative damages in mammals. The survival ratio of C. elegans rapidly decreased by the uptake of nanoparticles from their L4 larval stage with resulting in shortened lifespan (20 d). Both reproduction rate and body size of C. elegans were also reduced after exposure to 100 μg mL⁻¹ of fullerol. We found ectopic cell corpses caused by apoptotic cell death in the adult worms grown with fullerol nanoparticles. By the mutation of core pro-apoptotic regulator genes, ced-3 and ced-4, these nanoparticle-induced cell death were significantly suppressed, and the viability of animals consequently increased despite of nanoparticle uptake. The apoptosis-mediated toxicity of nanoparticles particularly led to the disorder of digestion system in the animals containing a large number of undigested foods in their intestine. These results demonstrated that the water-soluble fullerol nanoparticles widely used in medicinal applications have a potential for inducing apoptotic cell death in multicellular organisms despite of their antioxidative detoxifying property.     

Identification of priority pharmaceuticals in the water environment of China

In recent years, increasing attention has been paid to the trace-level contamination of pharmaceuticals in the water environment all over the world. Considering a large number of pharmaceuticals used, it is crucial to establish a priority list of pharmaceuticals that should be monitored and/or treated first. In the present study, we developed a ranking system based on the pharmaceutical consumption, removal performance in the wastewater treatment plants (WWTPs) and potential ecological effects, and applied to the situation of China. 39 pharmaceuticals, which had available consumption data and also been reported previously in the WWTPs of China, were selected as candidate pharmaceuticals. Among them, seventeen pharmaceuticals were considered as priority pharmaceuticals, out of which, erythromycin, diclofenac acid and ibuprofen, had the high priority. Compared with other literatures, we found that some pharmaceuticals given concerns to globally should also be included in the priority list in China; while some pharmaceuticals, not mentioned in other literatures, such as cefalexin, ketoconazole, should be also given prior consideration in China. Among all the therapeutic classes, antibiotics, which were grossly abused in China, contributed the most to the priority pharmaceuticals. However, priority antibiotics accounted for only 32% of candidate antibiotics, while 71% and 100% of the candidate anti-inflammatory and antilipidemic respectively were identified as the priority pharmaceuticals, indicating that antibiotics might be overanxiously considered in the previous studies on their behaviors in the WWTPs of China.     

Determination of partition and diffusion coefficients of formaldehyde in selected building materials and impact of relative humidity

The partition and effective diffusion coefficients of formaldehyde were measured for three materials (conventional gypsum wallboard, "green" gypsum wallboard, and "green" carpet) under three relative humidity (RH) conditions (20%, 50%, and 70% RH). The "green" materials contained recycled materials and were friendly to environment. A dynamic dual-chamber test method was used. Results showed that a higher relative humidity led to a larger effective diffusion coefficient for two kinds of wallboards and carpet. The carpet was also found to be very permeable resulting in an effective diffusion coefficient at the same order of magnitude with the formaldehyde diffusion coefficient in air. The partition coefficient (K(ma)) of formaldehyde in conventional wallboard was 1.52 times larger at 50% RH than at 20% RH, whereas it decreased slightly from 50% to 70% RH, presumably due to the combined effects of water solubility of formaldehyde and micro-pore blocking by condensed moisture at the high RH level. The partition coefficient of formaldehyde increased slightly with the increase of relative humidity in "green" wallboard and "green" carpet. At the same relative humidity level, the "green" wallboard had larger partition coefficient and effective diffusion coefficient than the conventional wallboard, presumably due to the micro-pore structure differences between the two materials. The data generated could be used to assess the sorption effects of formaldehyde on building materials and to evaluate its impact on the formaldehyde concentration in buildings.     

山地城市暴雨径流污染特性及控制对策

为了解山城重庆的暴雨径流污染特性,充实国内仍然薄弱的基础资料,对4种用地类型的4场暴雨进行了监测,测试指标包括TSS、COD、TP、TN和NH3-N。结果表明,对于坡度2.5%的交通干道和坡度30%的校园人行道,从污染物浓度降幅的角度考虑初期径流的控制量应分别为2～3 mm和1.8 mm。随降雨时间的延长,路面污染物浓度迅速降低,坡度越大,降低速率越快。对于平均浓度,校园屋顶和草坪的各污染物浓度均达到地表水环境质量Ⅴ类标准(总氮和氨氮除外)。交通干道和校园人行道的总磷平均浓度也满足地表水环境质量Ⅴ类标准,但2种下垫面的COD、TN和氨氮平均浓度分别超出地表水环境质量Ⅴ类标准的2～8倍、1.9～3.1倍和1.9～4.3倍。对于交通干道,场次降雨径流的总氮、总磷和氨氮平均浓度与初期浓度的比值和污染物浓度20 min降幅接近(分别为0.5～0.53和50%～55%)接近,而COD和TSS平均浓度与初期浓度的比值和污染物浓度20 min降幅相近(分别为0.35～0.37和78%～84%)。对于校园人行道,污染物浓度20 min降幅均达到90%以上(90%～96%),场次降雨径流的总氮、总磷、氨氮、COD和TSS的平均浓度与初期浓度的比值接近(0.3～0.4)。研究结果为山地城市暴雨径流的污染控制提供了参考。     

基于主成分分析法的武汉城市圈区域协调发展研究

在"两型社会"背景下,如何实现武汉城市圈的快速发展及圈内的协调发展是促进武汉城市圈建设与发展的重要内容,也是构建中国中部区域板块新经济增长极的必然选择。采用统计数据、利用主成分分析法对武汉城市圈区域经济发展进行评价,利用数学模型对武汉城市圈区域发展的不平衡性与区域差异性进行分析,在此基础上提出发展地方特色经济,加强区域经济间的联系,实现产业一体化与经济一体化,建立统一的监督机构,实现武汉城市圈的协调发展。     

Impact of roadside noise barriers on particle size distributions and pollutants concentrations near freeways

Increasing epidemiological evidence has established an association between a host of adverse health effects and exposure to ambient particulate matter (PM) and co-pollutants, especially those emitted from motor vehicles. Although PM and their co-pollutants dispersion profiles near the open freeway have been extensively characterized by means of both experimental measurements and numerical simulations in recent years, such investigations near freeways with roadside barriers have not been well documented in the literature. A few previous studies suggested that the presence of roadside structures, such as noise barriers and vegetation, may impact the decay of pollutant concentrations downwind of the freeway by limiting the initial dispersion of traffic emissions and increasing their vertical mixing due to the upward deflection of airflow. Since the noise barriers are now common roadside features of the freeways, particularly those running through populated urban areas, it is pertinent to investigate the impact of their presence on the particles and co-pollutants concentrations in areas adjacent to busy roadways. This study investigated two highly trafficked freeways (I-710 and I-5) in Southern California, with two sampling sites for each freeway, one with and the other without the roadside noise barriers. Particle size distributions and co-pollutants concentrations were measured in the immediate proximity of freeways and at different distances downwind of the freeways. The results showed the formation of a “concentration deficit” zone in the immediate vicinity of the freeway with the presence of roadside noise barrier, followed by a surge of pollutant concentrations further downwind at 80–100 m away from freeway. The particle and co-pollutants concentrations reach background levels at farther distances of 250–400 m compared to 150–200 m at the sites without roadside noise barriers.     

胶束强化超滤去除水中双酚A

采用截留分子量(MWCO)为5000 Dalton、1000 Dalton的聚砜超滤膜,MWCO为1 kDa的再生纤维素超滤膜;采用十二烷基苯磺酸钠(SDBS)、曲拉通100(TritonX-100)、吐温80(Tween-80)、烷基多苷(APG)为表面活性剂,用胶团强化超滤工艺去除水中双酚A。研究了不同材质和截留分子量的超滤膜、表面活性剂浓度、膜操作压力、溶液pH和溶液中电解质等因素对该工艺的影响。结果表明,SDBS对双酚A有较好的去除效果,去除率在80%以上。在H+和Na+存在的条件下,双酚A的截留率增加,透过液中SDBS浓度降低。SDBS与非离子表面活性剂的复配可以提高双酚A截留率,降低透过液中SDBS的浓度,复配效果优劣顺序为Tween-80TritonX-100APG。     

PVA降解菌的复配组合及其紫外诱变处理的研究

对已筛选出的4株PVA降解菌进行不同的组合后测定PVA降解率,发现Z5与Z8菌株混合后在1周内对PVA的去除率达到了所有组合中的最高值52.07%,比单菌株提高了约22%。采用紫外照射的方法对混合菌进行诱变并利用正交实验研究其特性,结果表明,诱变后的混合菌在1周内降解了91.46%的PVA,并且碳源浓度对酶活的影响最为显著。当pH为7,碳源、氮源含量分别为1.5 g/L、0.6 g/L,NaC l浓度为1.5 g/L时,诱变菌株处于最佳生长状态。