Spatial distribution of health risks for residents located close to solvent-consuming industrial VOC emission sources

Emissions derived from the consumption of organic solvents have been proven to be the primary industrial source of volatile organic compounds (VOCs). In conjunction with epidemiologic studies, water-based paints (WBPs) and solvent-based paints (SBPs) were selected as representatives of newly developed solvents and traditional solvents, respectively, to simulate the effects of consuming solvents emitted during industrial production. And non-carcinogenic and carcinogenic risks to residents near emission sources were studied in detail. The results showed that the spatial distribution of health risks varied with meteorological conditions and type of emission source, and the prevailing wind direction strongly affected the distribution range and shape of the influenced area. The areas of influence maximized on heavy-polluting days for both WBP and SBP emission sources with the total span reaching 804 m and 16 km, respectively; meanwhile, the areas of influence for carcinogenic risk resulting from WBP emission sources were 1.2 and 2.3 times greater than those measured on fine and rainy days, respectively, and 1.8 and 2.9 times greater for SBP emission sources. Compared with WBPs, the total spans of negatively influenced regions resulting from SBP emission sources were 10.4, 12.5 and 19.9 times greater on fine, rainy and heavy-polluting days, respectively. Therefore, carcinogenic risk was the dominant health threat for populations residing close to solvent-consuming industrial emission sources. The findings suggest that newly developed solvents are capable of significantly reducing consequent health threats, nevertheless, they could still pose occasional threats to nearby residents under specific meteorological conditions.     

四氯化硅综合利用模式的建立与可行性分析

随着国内多晶硅产业的快速发展,多晶硅主要副产物四氯化硅的环境污染问题日益突出,有效利用四氯化硅、减少环境污染是当前急需解决的问题。提出了采用循环经济理念,建立以多晶硅产业为中心的生态工业园区来解决四氯化硅综合利用难题,并从技术、经济和政策上作可行性分析,得出建立以多晶硅产业为中心的生态工业园区是解决我国多晶硅行业四氯化硅综合利用难题的有效方法和途径。     

The effects of developmental lead (Pb) exposure on the expression of the CTGF and TGF-β1 in hippocampus of pups

Pregnant mice were exposed to control (0%), low (0.1%), moderate (0.5%), and high (1%) lead (Pb) acetate in deionized drinking water from the first day of gestation to postnatal day (PND) 21. Pb concentration was determined in blood and the hippocampus at the 7th, 14th, or 21st day of neonatal mice pups. The expression of connective tissue growth factor (CTGF) and TGF-β1 mRNA and protein was also measured in the hippocampus using RT-PCR and immunohistochemistry assays. The expression of CTGF and TGF-β1 mRNA was up-regulated in hippocampus in Pb-exposed groups. These results were further confirmed by immunohistochemistry staining. Data suggest that CTGF and TGF-β1 genes are differentially regulated and are affected by Pb.     

Size-resolved aerosol ionic composition and secondary formation at Mount Heng in South Central China

To understand the size-resolved aerosol ionic composition and the factors influencing secondary aerosol formation in the upper boundary layer in South Central China, size-segregated aerosol samples were collected using a micro-orifice uniform deposit irnpactor （MOUDI） in spring 2009 at the summit of Mount Heng （1269 m asl）, followed by subsequent laboratory analyses of 13 inorganic and organic water-soluble ions. During non- dust-storm periods, the average PM1.8 concentration was 41.8 μg·m^-3, contributing to 55% of the PM10. Sulfates, nitrates, and ammonium, the dominant ions in the fine particles, amounted to 46.8% of the PM1.8. Compared with Mount Tai in the North China Plain, the concentrations of both fine and coarse particles and the ions contained therein were substantially lower. When the air masses from Southeast Asia prevailed, intensive biomass burning there led to elevated concentrations of sulfates, nitrates, ammonium, potassium, and chloride in the fine particles at Mount Heng. The air masses originating from the north Gobi brought heavy dust storms that resulted in the remarkable production of sulfates, ammonium, methane sulfonic acid, and oxalates in the coarse particles. Generally, the sulfates were primarily produced in the form of （NH4）2SO4 in the droplet mode via heterogeneous aqueous reactions. Only approximately one-third of the nitrates were distributed in the fine mode, and high humidity facilitated the secondary formation of fine nitrates. The heterogeneous formation of coarse nitrates and ammonium on dry alkaline dust surfaces was found to be less efficient than that on the coarse particles during non-dust-storm periods.     

2,2’,4,4’-四溴联苯醚对大型溞的毒性效应

以实验室培养的大型溞为受试生物,进行了2,2’,4,4’-四溴联苯醚(BDE-47)对大型溞的48h急性毒性实验和21d慢性毒性实验,并研究了暴露在不同质量浓度和处理时间的BDE-47中,大型溞的抗氧化酶系中的超氧化物歧化酶(SOD)和谷胱甘肽硫转移酶(GST)的酶活性变化。结果表明,BDE-47对大型溞的48h的半致死浓度为1.04mg·L-1,属于高毒物质;在BDE-47慢性毒性实验低浓度处理组中,大型溞的体长及繁殖能力受到了抑制,而高浓度处理组中大型溞的体长及繁殖能力上升,其中第一次产仔数和产卵总数是表征BDE-47慢性毒性的最灵敏参数。随着BDE-47浓度的增加,大型溞SOD和GST活性均呈现出低浓度诱导高浓度抑制的现象。SOD和GST均表现出一定的敏感性,但相对SOD,GST对BDE-47暴露更为敏感。     

Characterization of humic substances in bio-treated municipal solid waste landfill leachate

Considerable organic matter remains in municipal solid waste landfill leachate after biological treatments. Humic substances (HSs) dominate the organic matter in bio-treated landfill leachate. In this study, the HSs from landfill leachate treated by membrane bioreactor (MBR-HSs) were analyzed via elemental analysis, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, and charge polarized magic-angle spinning-¹³C-nuclear magnetic resonance. The characteristic absorption in the UV wavelength range indicated the presence of high C=C and C=O double bonds within the MBR-HSs. Compared with commercial HSs, MBR-HSs had lower carbon content [48.14% for fulvic acids (FA) and 49.52% for humic acids (HA)], higher nitrogen content (4.31% for FA and 6.16% for HA), lower aromatic structure content, and higher carbohydrate and carboxylic atoms of carbon content. FA predominantly had an aliphatic structure, and HA had less condensed or substituted aromatic ring structures than natural HA. The aromatic carbon content of MBR-HSs was lower than that of humus-derived HSs but higher than that of waste-derived HSs, indicating that MBR-HSs appeared to be more similar to humus-derived HSs than waste-derived HA.     

Cement-based solidification/stabilization of contaminated soils by nitrobenzene

The cement-based solidification/stabilization (S/S) of nitrobenzene (NB) contaminated soils, with cement and lime as binders, sodium silicate solution and powder activated carbon (PAC) as additives, was optimized through an orthogonal experiment, and S/S efficiency was estimated by both leaching test and volatilization measurement. The leaching test results showed that the factors affecting S/S efficiency were NB concentration, cement-to-lime ratio and binder-to-soils ratio, in sequence. With increasing curing time, the leaching concentration of NB between different levels of the same factor in the orthogonal experiment decreased, and less than 9% NB leached out from the 28 d cured samples. The volatilization measurement results indicated that 0.5‰ of NB was volatilized during the mixing and curing processes for the samples without PAC in the 28 d cycle, whereas adding 2 wt% and 5 wt% PAC, with respect to the weight of contaminated soils, could reduce NB volatilization to half of its original values either during the mixing or curing process. The optimizing formula, that is, contaminated soils (dry weight):cement:lime= 100:25:25, with 5 wt% additional sodium silicate and 2 wt% additional PAC, was applied to the engineering application of NB contaminated soils. Both the leaching test results of the product and the ambient air quality monitoring results met related regulations during the treating process.     

Research and practice on fluctuation water injection technology at low permeability coal seam

In order to solve the problem of poor affusion effect on low permeability coal seam, the paper analyzes the micro process of the coal seam water infusion in wetting coal and determines the main factors affecting coal seam water infusion. The permeability of the NO.3 coal seam in east working face of Xingcun coal mine by MTS815.03 servo-controlled rock mechanical test system has been tested. Results show that when the peak stress in coal sample specimens reaches 48.53 MPa, permeability ranges from 0.5158 to 2.9576 × 10⁻⁸ Darcy, and it means that the coal seam is low in permeability and difficult in water injection. Based on the characteristics of low permeability and geostress situation, efficient fluctuation water injection technology with permeable agent and relevant process parameters have been designed. The surface tension of the permeable agent developed here is 31.18 m N/m when mass concentration reaches 0.05%. The permeable agent can permeate into 2 cm thick coal layer completely in 10 s, thus improving the wettability of water effectively and the water injection pressure fluctuates between 7 MPa and 25 MPa. The application of the technique in the 3rd coal seam in east working face of Xingcun coal mine shows not only single-arch injection experienced a significant increase on average, from no more than 10 m³ to 63.3886 m³, but also the effect of dust fall, cooling and rock burst prevention is remarkable.     

Removal of clofibric acid from aqueous solution by polyethylenimine-modified chitosan beads

Polyethylenimine （PEI）-modified chitosan was prepared and used to remove clofibric acid （CA） from aqueous solution. PEI was chemically grafted on the porous chitosan through a crosslinking reaction, and the effects of PEI concentration and reaction time in the preparation on the adsorption of clofibric acid were optimized. Scanning electron microscopy （SEM） showed that PEI macromolecules were uniformly grafted on the porous chitosan, and the analysis of pore size distribution indicated that more mesopores were formed due to the crosslinking of PEI molecules in the macropores of chitosan. The PEI-modified chitosan had fast adsorption for CA within the initial 5 h, while this adsorbent exhibited an adsorption capacity of 349 mg· g^-1 for CA at pH 5.0 according to the Langmuir fitting, higher than 213 mg· g^-1 on the porous chitosan. The CA adsorption on the PEI- modified chitosan was pH-dependent, and the maximum adsorption was achieved at pH 4.0. Based on the surface charge analysis and comparison of different pharmaceu- ticals adsorption, electrostatic interaction dominated the sorption of CA on the PEI-modified chitosan. The PEI- modified chitosan has a potential application for the removal of some anionic rnicropollutants from water or wastewater.     

中国老年人驾车安全问题及其对策

随着中国进入老龄化社会,老年驾驶员数量将持续增加,这给交通安全带来了新的问题。为保障老年驾驶员的交通安全,在分析老年人生理和心理特征以及老年驾驶员交通事故特点的基础上,提出了适合中国国情的老年驾驶员驾车安全对策。