天然气输送管道泄漏事故危害定量分析

针对某市天然气利用工程中高压输送管道可能发生的天然气泄漏的危险性进行分析 ,求出了其最大的泄漏流量。通过高斯扩散模式定量计算在大气为中性条件下 ,天然气在大气中的轴向、径向和切向的扩散距离 ,从而计算出该天然气 -空气混合云团的体积。对该体积预混云团的火灾危害进行评估 ,计算形成火球的参数 ,用热辐射剂量准则计算其伤害半径。对该预混云团可能产生的爆轰后果 ,采用超压准则计算其对人员和建筑物的伤害半径。并用热辐射强度准则对可能产生稳态燃烧进行了危害半径的计算     

Estrogen-related receptor disruption of source water and drinking water treatment processes extracts

Environmental chemicals in drinking water can impact human health through nuclear receptors. Additionally, estrogen-related receptors (ERRs) are vulnerable to endocrine-disrupting e ects. To date, however, ERR disruption of drinking water potency has not been reported. We used ERR two-hybrid yeast assay to screen ERR disrupting activities in a drinking water treatment plant (DWTP) located in north China and in source water from a reservoir, focusing on agonistic, antagonistic, and inverse agonistic activity to 4-hydroxytamoxifen (4-OHT). Water treatment processes in the DWTP consisted of pre-chlorination, coagulation, coal and sand filtration, activated carbon filtration, and secondary chlorination processes. Samples were extracted by solid phase extraction. Results showed that ERR antagonistic activities were found in all sample extracts, but agonistic and inverse agonistic activity to 4-OHT was not found. When calibrated with the toxic equivalent of 4-OHT, antagonistic e uent e ects ranged from 3.4 to 33.1 g/L. In the treatment processes, secondary chlorination was e ective in removing ERR antagonists, but the coagulation process led to significantly increased ERR antagonistic activity. The drinking water treatment processes removed 73.5% of ERR antagonists. To our knowledge, the occurrence of ERR disruption activities on source and drinking water in vitro had not been reported previously. It is vital, therefore, to increase our understanding of ERR disrupting activities in drinking water.     

Aggregation pheromone compounds of the black larder beetle Dermestes haemorrhoidalis Kuster (Coleoptera: Dermestidae)

Gas chromatography with simultaneous flame ionisation and electroantennographic detection (GC–EAD) and gas chromatography with mass spectrometry analysis (GC–MS) of abdominal extracts of adult male Dermestes haemorrhoidalis Kuster (Coleoptera: Dermestidae) revealed the presence of electrophysiologically and behaviourally active compounds to its conspecific males and females. Isopropyl dodecanoate (3), isopropyl (Z)-9-tetradecenoate (5), isopropyl tetradecanoate (6), isopropyl (Z)-9-hexadecenoate (7) and isopropyl hexadecanoate (8) were detected in male abdominal extracts only. Analysis of collected male headspace volatiles revealed the presence of six EAD-active compounds (3), (5), (6) and isopropyl tridecanoate (4) plus two unidentified compounds (1) and (9). Synthetic compounds (3), (4), (5), (6) and (7) showed EAD activity with antennae of both sexes in contrast to synthetic (8) which showed EAD activity with female antennae only. Male and female antennae of D. haemorrhoidalis reacted with high receptor potentials to isopropyl (Z)-9-dodecenoate (2), although this compound itself was detected in neither male nor female abdominal extracts or headspace volatiles. Petri dish bioassays indicated that male abdominal extracts and compounds (2), (3), (5) and (6) aroused and attracted conspecific male and female beetles significantly (P < 0.05) compared to female extracts. These results suggested the presence of a male-produced aggregation pheromone in D. haemorrhoidalis. Field assays with any of the described compounds, however, did not result in attraction of this beetle in significant numbers.     

Nanomaterials for environmental burden reduction, waste treatment, and nonpoint source pollution control: a review

Nanomaterials are applicable in the areas of reduction of environmental burden, reduction/treatment of industrial and agricultural wastes, and nonpoint source (NPS) pollution control. First, environmental burden reduction involves green process and engineering, emissions control, desulfurization/denitrification of nonrenewable energy sources, and improvement of agriculture and food systems. Second, reduction/treatment of industrial and agricultural wastes involves converting wastes into products, groundwater remediation, adsorption, delaying photocatalysis, and nanomembranes. Third, NPS pollution control involves controlling water pollution. Nanomaterials alter physical properties on a nanoscale due to their high specific surface area to volume ratio. They are used as catalysts, adsorbents, membranes, and additives to increase activity and capability due to their high specific surface areas and nano-sized effects. Thus, nanomaterials are more effective at treating environmental wastes because they reduce the amount of material needed.     

Distribution of aromatic amines,phenols, chlorobenzenes,and naphthalenes in the surface sediment of the Dianchi Lake,China

• The total organic pollutant concentrations in sediment were 27.4-1620 ng/g. • The phenol concentrations were relatively high in the sediment of the Dianchi Lake. • Average total concentrations decreased as follows: Caohai>Waihai>Haigeng Dam. • 1,4-dichlorobenzene, 3- or 4-methylphenol, 1,2,4-trichlorobenzene might be risks. Organic pollutants are widespread environmental pollutants with high toxicity, persistence, and bioaccumulation. Our aim was to investigate the distribution of aromatic amines, phenols, chlorobenzenes, and naphthalenes in the surface sediment of the Dianchi Lake, China. Nineteen surface sediment samples were collected from the Dianchi Lake, and 40 types of organic pollutants were analyzed via gas chromatography–mass spectrometry. The total organic pollutant concentrations in the surface sediment of the Dianchi Lake varied from 27.4 to 1.62 × 10³ ng/g. The concentrations of phenols were much higher than those in other water bodies but still within a controllable range, whereas the concentrations of the other organic pollutant classes were similar or even lower. The detection ratio of 3- or 4-methylphenol was the highest (100.00%) among the pollutants. The average total organic pollutant concentrations decreased in the following order: Caohai (540 ng/g)>the middle of Waihai (488 ng/g)>the edge of Waihai (351 ng/g)>Haigeng Dam (90.4 ng/g). Pearson analysis showed a strong correlation among 1-methylnaphthalene, 2-methylnaphthalene, 1,3-dinitronaphthalene, and 1,4-dinitronaphthalene (p<0.01). Caohai, the north lakeshore of Waihai and the south of Waihai showed higher risk because of high concentration; meanwhile, 1,4-dichlorobenzene, 3- or 4-methylphenol and 1,2,4-trichlorobenzene were more likely to cause risks.     

BTEX exposures in an area impacted by industrial and mobile sources: Source attribution and impact of averaging time

The impacts of emissions plumes from major industrial sources on black carbon (BC) and BTEX (benzene, toluene, ethyl benzene, xylene isomers) exposures in communities located >10 km from the industrial source areas were identified with a combination of stationary measurements, source identification using positive matrix factorization (PMF), and dispersion modeling. The industrial emissions create multihour plume events of BC and BTEX at the measurement sites. PMF source apportionment, along with wind patterns, indicates that the observed pollutant plumes are the result of transport of industrial emissions under conditions of low boundary layer height. PMF indicates that industrial emissions contribute >50% of outdoor exposures of BC and BTEX species at the receptor sites. Dispersion modeling of BTEX emissions from known industrial sources predicts numerous overnight plumes and overall qualitative agreement with PMF analysis, but predicts industrial impacts at the measurement sites a factor of 10 lower than PMF. Nonetheless, exposures associated with pollutant plumes occur mostly at night, when residents are expected to be home but are perhaps unaware of the elevated exposure. Averaging data samples over long times typical of public health interventions (e.g., weekly or biweekly passive sampling) misapportions the exposure, reducing the impact of industrial plumes at the expense of traffic emissions, because the longer samples cannot resolve subdaily plumes. Suggestions are made for ways for future distributed pollutant mapping or intervention studies to incorporate high time resolution tools to better understand the potential impacts of industrial plumes.

Implications: Emissions from industrial or other stationary sources can dominate air toxics exposures in communities both near the source and in downwind areas in the form of multihour plume events. Common measurement strategies that use highly aggregated samples, such as weekly or biweekly averages, are insensitive to such plume events and can lead to significant under apportionment of exposures from these sources.     

Interaction of diuron to human serum albumin: Insights from spectroscopic and molecular docking studies

This investigation was undertaken to determine the interaction of diuron with human serum albumin (HSA) was studied by monitoring the spectral behavior of diuron-HSA system. The fluorescence of HSA at 340 nm excited at 230 nm was obviously quenched by diuron due to dynamic collision and the quenching constant was of the order of 10⁴ L mol^?1 at 310 K. However, no fluorescence quenching was observed when excited at 280 nm. Thermodynamic investigations revealed that the combination between diuron and HSA was entropy driven by predominantly hydrophobic interactions. The binding of diuron induced the drastic reduction in α-helix conformation and the significant enhancement in β-turn conformation of HSA. In addition, both sites marker competition study and molecular modeling simulation evidenced the binding of diuron to HSA primarily took place in subdomain IIIA (Sudlow's site II).     

Exploitation of subabul stem lignin as a matrix in controlled release agrochemical nanoformulations: a case study with herbicide diuron

The utilization of nanomaterials in the domain of agriculture is at an inception, especially in the development of controlled release agrochemical nanoformulations. The present study demonstrated the potential of subabul stem lignin as a matrix material in agrochemical formulations using nanotechnology. In this study, “nanoprecipitation” method was employed and “optimized” to fabricate a stable herbicide, “diuron nanoformulation” (DNF). “Optimized DNF” (ODNF) has 5.17?±?0.49 % diuron loading efficiency (DLE) and 74.3?±?4 % encapsulation efficiency (EE). The size of nanoparticles in ODNF was 166?±?68 nm as revealed by FESEM/TEM studies. Physicochemical characterization of ODNF by UV, FT-IR, and DSC studies revealed the successful loading of diuron within the lignin matrix. The ODNF exhibited nonlinear biphasic release profile for diuron. Further, the bioefficacy of diuron released from ODNF was tested using canola (Brassica rapa). B. rapa seedlings grown in the soil supplemented with ODNF showed early signs of leaf chlorosis and mortality when compared with seedlings grown in the presence of commercial diuron formulation (CDF) or bulk diuron (BD), respectively. This study not only revealed the exploitation of subabul stem lignin as a “matrix” in the controlled release nanoformulation of diuron but also opened up new avenues for utilizing it as matrix for several other agrochemicals associated with the growth and development of the plant.     

抗生素最小抑制浓度法(MICs)评估环境大肠杆菌抗生素抗性

2015年世界卫生组织将抗生素的滥用列为21世纪最大的挑战之一,全球范围内抗生素抗药性的散播已严重威胁人类的健康。如何检测环境中的细菌抗药性,并有效评估抗药性感染的风险,是环境微生物研究的一项重要课题。本文通过改进的培养基微量稀释(broth micro-dilution)法,确定了2个地区(中国成都和美国夏威夷)不同环境来源(天然水系和市政污水)的大肠杆菌的抗生素最小抑制浓度(minimum inhibitory concentrations,MICs)。计算所得的MIC分位数(MIC50和MIC90)、菌体抗性百分比及多抗药性指数(multiple antibiotic resistance indexes,MARIs)显示两地不同环境区划的抗生素抗性存在明显的差异。天然水系(成都锦江)中的抗生素抗性是随时间可变的,与当地的降雨事件相关。环境菌株的抗药性模式通过聚类和非度量多维测度(non-metric multidimensional scaling,NMDS)进行分析。广谱β-内酰胺酶基因筛查显示出抗性基因与抗性表型之间的正相关性。结合现有的两地抗生素的使用数据讨论了两地环境抗生素抗性与当地人类活动及抗生素的使用实践之间的紧密联系。采集环境菌株抗生素MIC数据的实验及数据分析方法实现了环境抗药性的跨时空对比,为规范抗生素的区域性使用提供了指导作用。     

Characterization of Super Paramagnetic Nanoparticles Coated with a Biocompatible Polymer Produced by Dextransucrase from <Emphasis Type="Italic">Weissella cibaria</Emphasis> JAG8

Magnetic nanoparticles (MNPs) synthesised by chemical co-precipitation method was subjected to dextran coating by sonication method. The dextran was enzymatically synthesised by extracellular dextransucrase isolated from Weissella cibaria JAG8. The crystalline nature of MNPs and dextran coated MNPs were confirmed by X-ray diffraction studies with average particle size of 25 nm, which was confirmed further by high resolution transmission electron microscopy. The surface morphology of MNPs and dextran coated MNPs were monitored by scanning electron microscopy studies. The vibrating sample magnetometer investigation displayed the super paramagnetic nature of MNPs and dextran coated MNPs. FT-IR analysis of MNPs and dextran coated MNPs, displayed characteristic band of Fe–O bond at 582 cm^?1. Thermo-gravimetric analysis of MNPs and dextran coated MNPs (1:1) ratio displayed a weight loss of 15 and 18 %, which clearly indicated 3.0 % of dextran was coated on to the MNPs. The elemental composition study by scanning electron microscopy confirmed the association of dextran with MNPs. The in vitro effect of MNPs and dextran coated MNPs was performed on human colon cancer (HT-29) cell lines and the results showed that dextran coated: MNPs (2:1) displayed good biocompatibility results over dextran coated: MNPs (1:1) and un-coated MNPs.