城市大气环境治理成本核算及其总量、结构分析——以西安市为例

基于单位成本分析模型对2000—2009年西安市大气环境治理的价值量进行了系统核算,并从总量与结构两方面对核算结果进行了深入和全面的分析。结果表明,从西安市历年大气环境的实际治理成本(除2002、2006、2009年)来看,该市在大气环境治理方面的投资基本上逐年增加,但是增加幅度较小,而大气环境虚拟治理成本在一般年份(除2002、2006、2009年)总体上呈现先增加后减小的变化趋势。可见,西安市为改变环境污染状况,不断增加大气环境治理方面的投资,但在初期治理资金缺口仍在增加,而随着投资的持续增加,许多大气环境治理设施的建立与作用的发挥,大气环境污染状况逐渐减轻,治理资金缺口开始变小;在核算年份中,西安市工业大气环境污染治理的重点主要放在了烟尘方面,城镇生活SO2虚拟治理成本在生活废气总虚拟治理成本中所占比例最高。最后,针对发现问题,对该市今后大气环境治理工作的方向和措施给出了建议。     

Enhanced electrokinetic remediation of lead-contaminated soil by complexing agents and approaching anodes

Optimizing process parameters that affect the remediation time and power consumption can improve the treatment efficiency of the electrokinetic remediation as well as determine the cost of a remediation action. Lab-scale electrokinetic remediation of Pb-contaminated soils was investigated for the effect of complexant ethylenediaminetetraacetic acid (EDTA) and acetic acid and approaching anode on the removal efficiency of Pb. When EDTA was added to the catholyte, EDTA dissolved insoluble Pb in soils to form soluble Pb–EDTA complexes, increasing Pb mobility and accordingly removal efficiency. The removal efficiency was enhanced from 47.8 to 61.5 % when the EDTA concentration was increased from 0.1 to 0.2 M, showing that EDTA played an important role in remediation. And the migration rate of Pb was increased to 72.3 % when both EDTA and acetic acid were used in the catholyte. The “approaching anode electrokinetic remediation” process in the presence of both EDTA and acetic acid had a higher Pb-removal efficiency with an average efficiency of 83.8 %. The efficiency of electrokinetic remediation was closely related to Pb speciation. Exchangeable and carbonate-bounded Pb were likely the forms which could be removed. All results indicate that the approaching anode method in the presence of EDTA and acetic acid is an advisable choice for electrokinetic remediation of Pb-contaminated soil.     

Urinary metabolomic profiling in rats exposed to dietary di(2-ethylhexyl) phthalate (DEHP) using ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS)

Di(2-ethylhexyl) phthalate (DEHP) is an omnipresent environmental chemical with widespread nonoccupational human exposure through multiple ways. Although considerable efforts have been invested to investigate mechanisms of DEHP toxicity, the key metabolic biomarkers of DEHP toxicity remain to be identified. The aim of this study was to assess the urinary metabonomics of dietary DEHP in rats using the technique of ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS). Fourteen female Wistar rats were divided into two groups and given increasing dietary doses of DEHP for 30 consecutive days. The urinary metabolite profile was studied using ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) enabled clusters to be clearly separated. Eleven principal urinary metabolites were identified as contributing to the clusters. The clusters in the positive electrospray ionization (ESI) mode were xanthurenic acid, kynurenic acid, nonate, N6-methyladenosine, and L-isoleucyl-L-proline. The clusters in the negative ESI mode were hippuric acid, tetrahydrocortisol, citric acid, phenylpropionylglycine, cPA(18:2(9Z, 12Z)/0:0), and LysoPC(14:1(9Z)). The urinary metabonomic changes indicated that exposure to dietary DEHP can affect energy-related metabolism, liver and renal function, fatty acid metabolism, and cause DNA damage in rats. The findings of this study on the urinary metabolites and metabolic pathways of DEHP may form the basis for future studies on the mechanisms of toxicity of this commonly found environmental chemical.     

实时气体分析在控制炼钢过程中的应用

电弧炉二次燃烧和转炉煤气回收是炼钢过程中2个最重要的节能降耗手段.而这2个过程中都需要对气体浓度进行实时分析来反馈控制工艺过程.分析了这两个过程中的气体实时分析的重要性,并对正在开发的激光气体分析系统进行了简要介绍.     

浅析PCB废水中络合态铜的处理方法

在PCB废水中,铜是主要的重金属污染物。Cu^2＋可通过加碱沉淀法完全沉淀下来,而废水中含有的络合态铜往往是造成出水总铜不能达标排放的重要因素。本文对络合态铜的各种处理方法如：化学沉淀法、氧化还原法、生物法等作了简要介绍和分析。     

光学检测法用于工业气体检测的研究

开展基于特定物质吸收光谱及其谐波检测技术的气体检测装置的实验研究.检测装置采用频率稳定措施,使激光频率始终控制在待测气体的吸收谱线上,对环境的抗干扰能力强,不会产生误判.不需要经常标定,不需要采样.     

中国与美国对外直接投资区位选择的比较研究

基于邓宁的国际生产折衷理论,对比了中美两国投资规模、空间分布和发展阶段,利用灰色关联分析法比较了影响两国投资区位的因子.结果表明,影响美国对外投资的主要因子是人均GNP、CH和CO2的排放量,影响中国的主要因子是直接投资净流入量、航空运输量和CPI;美国对外直接投资属于市场导向型,而中国尚处于转型期,为对外投资第三阶段.     

Behaviour of selected endocrine-disrupting chemicals in three sewage treatment plants of Beijing, China

Occurrence and fate of eight kinds of selected endocrine-disrupting compounds (EDCs) in three sewage treatment plants (STPs) of Beijing, China was investigated. These EDCs, composed of 4-octylphenol (4-OP), 4-n-nonylphenol (4-n-NP), bisphenol A (BPA), estrone (E1), 17α-estradiol (17α-E2), 17β-estradiol (E2), estriol (E3) and 17α-ethinylestradiol (EE2), in every step of STPs, were simultaneously analysed by gas chromatography/mass spectrometry after derivatisation. All the EDCs were detected in the influents of three STPs, and BPA was the most abundant compound. The concentrations of EDCs ranged from 36.6 ng/l of 17α-E2 (STP C) to 1342.3 ng/l of BPA (STP B) in the influent sewages and from below limits of detection of E2 and E3 (STP C) to 142.5 ng/l of E1 (STP B) in the effluent sewages. The STPs could not remove alkylphenols effectively from the aqueous phase with less than 40% reduction. BPA decreased over 90%, and steroid estrogens achieved considerable reductions from 64.8% of E2 to 94.9% of E3. Generally, biological treatment was more effective in removing alkylphenols, BPA and natural estrogens from the aqueous phase than primary treatment. However, the synthetic estrogen, EE2, was mostly removed by the primary treatment with about 63.5% reduction. It is the first time that the concentration of 17α-E2 in the sewage of China was reported in this paper. The compound might have a bearing with the waste effluents of dairy farms around urban area of Beijing.     

Seasonal temperatures have more influence than nitrogen fertilizer rates on cucumber yield and nitrogen uptake in a double cropping system

Two-year greenhouse cucumber experiments were conducted to investigate seasonal effects on fruit yield, dry matter allocation, and N uptake in a double-cropping system with different fertilizer management. Seasonal effects were much greater than fertilizer effects, and winter-spring (WS) cucumber attained higher fruit yields and N uptake than autumn-winter (AW) cucumber due to lower cumulative air temperatures during fruit maturation in the AW season. Fertilizer N application and apparent N loss under recommended N management (Nmr) decreased by 40-78% and 33-48% without yield loss compared to conventional N management (Nmt) over four growing seasons. However, there were no seasonal differences in N recommendations, taking into consideration seasonal differences in crop N demand, critical nutrient supply in the root zone and N mineralization rate.     

折板絮凝池流场的粒子图像测速试验研究

利用粒子图像测速(PIV)技术对折板絮凝池模型中的复杂流场进行测量,分析了折板絮凝池的缩放单元和转折单元内部流场对絮凝效果的影响机制.絮凝试验表明,90°异波折板与90°同波波折板组合的浊度去除率最高,达到了97.7%,这对折板絮凝池的成本效益设计提供了理论依据.