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301.
应用质量控制方法测定了2种国产商品多氯联苯中17个,2,3,7,8位有氯取代的二eying同族体,获得准确的定量结果,加入^13C标记物的PCBs样品用多级酸碱硅胶柱和氧化铝柱提取分离,用毛细管色谱/高分辨质谱定量,2种样品中都含有较多的2,3,7,8-TCDF和2,3,7,8P5CDF,1^#PCB的2,3,7,8-TCDD毒性当量值为217ng/g,2^#PCB为417ng/g,毒性主要来自P 相似文献
302.
A. Heil B. Langmann E. Aldrian 《Mitigation and Adaptation Strategies for Global Change》2007,12(1):113-133
Numerical modelling of fire-related smoke haze episodes in Southeast Asia is important for both prediction and assessment of atmospheric impacts, especially when observational data are fragmentary, as is the case in Indonesia. This work describes the atmospheric fate of smoke particles emitted during the 1997 Indonesian fires modelled with a regional atmospheric chemistry model. We established a new fire emission inventory and calculate that 55 teragram (Tg) of particulate matter and 1098 Tg of carbon were released during this fire episode. Our emission estimate is an intermediate value compared with other studies. Utilising different scenarios, we demonstrate the variable atmospheric impacts of surface vegetation fires and peat soil fires separately and also investigate the sensitivity of smoke dispersion to the differing meteorological conditions of an El Niño and a normal year. When peat fires are included in the emission inventory, modelled ambient particle concentrations exceed the ambient air quality standard across transboundary scales. In a scenario including only surface vegetation fires, ambient air quality standards are exceeded only in areas close to the main fires. This scenario demonstrates the prominent role of fires in peat areas in causing regional air pollution episodes. In years with normal meteorological conditions, intermittent precipitation and associated wet deposition during the dry season are predicted to remove most of the particulate emissions close to the sources. Strongly reduced rainfall and generally stronger southeasterly winds during El Niño years provide favourable conditions for larger scale smoke haze pollution. 相似文献
303.
以新建建筑产生的固体废弃物为研究对象,将改进的材料跟踪法、基于R语言的算法和数据挖掘技术相结合,合理规避了传统方法中数据提取粗糙与数据获取主观性强的问题.同时,通过现场调研获取全国不同区域新建居住建筑的基础数据,进行实证分析.结果表明,施工现场废弃混凝土、废弃钢筋、废弃砌块产生率的典型值分别为3.28%,2.88%,3.33%,代表区间分别为(0.6144%,5.9456%),(0.622%,5.138%),(0.6103%,6.02%).与已有数据对比发现,我国新建建筑中固体废弃物产生率高于定额损耗率,固废管理水平存在区域性差异,呈"沿海高、内地低"的态势,且整体减量化水平亟待提高. 相似文献
304.
305.
应用质量控制方法测定了2种国产商品多氯联苯(PCBs)中17个2,3,7,8位有氯取代的二 同族体,获得准确的定量结果,加入 ̄(13)C标记物的PCBs样品用多级酸碱硅胶柱和氧化铝柱提取分离,用毛细管色谱/高分辨质谱定量,2种样品中都含有较多的2,3,7,8-TCDF和2,3,7,8-P_5CDF。1 ̄#PCB的2,3,7,8-TCDD毒性当量值为217ng/g,2 ̄#PCB为417ng/g,毒性主要来自PCDFs,并与国外同类商品PCBs作了比较。 相似文献
306.
Hua Li Lin Cao Rong Sun Wenyi Dong Hongjie Wang Zhongyi Dai Xue Wang Jin Xie 《环境科学学报(英文版)》2023,35(2):758-768
To achieve advanced nitrogen removal from actual municipal sewage, a novel multistage anoxic/aerobic process with sludge regeneration zone (R-MAO) was developed. The reactor was used to treat actual domestic sewage and the nitrogen removal capacity of the sludge regeneration zone (R zone) was investigated during the long-term operation. The best performance was obtained at the R zone's Oxidation-Reduction Potential (ORP) of -50±30 mV and hydraulic residence times (HRT) of 1.2 hr. The average effluent COD, TN, NH4+-N and NO3−-N of the R-MAO process were 18.0±2.3, 7.5±0.6, 1.0±0.5 and 4.6±0.4 mg/L, respectively, with the corresponding removal efficiency of COD, TN and NH4+-N were 92.9%±1.0%, 84.1%±1.5% and 97.5%±1.1%. Compared to the sole MAO system, the TN removal efficiency of the R-MAO increased by 10.1%. Besides, under the optimal conditions, the contribution of the R zone in the R-MAO that removal COD, TN, NH4+-N and NO3−-N were 0.36, 0.15, 0.032 and 0.82 g/day. High-throughput sequencing results showed that uncultured_bacterium_f_Burkholderiaceae (5.20%), OLB8 (1.04%) and Ottowia (1.03%) played an important role in denitrification in the R zone. This study provided effective guidance for the design and operation of the R-MAO process in domestic sewage treatment. 相似文献
307.
308.
Natalicio Ferreira Leite Patricio Peralta-Zamor Marco Tadeu Grassi Yutao Zhang 《环境科学学报(英文版)》2011,23(6):904-911
The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in surface sediment samples from nine sites
located at the Iguac?u River Basin in the Metropolitan Region of Curitiba, Brazil to evaluate their distribution and sources. The total
concentration of the PAHs was greater for sediments from highly urbanized areas, while the sediments from the Ira′? Environmental
Protection Area (Ira′? EPA) showed significantly low concentrations. The sediments from the Iguac?u and Barigui rivers were classified
as highly contaminated, while those from the Cercado and Curralinho rivers were classified as moderately contaminated. The
predominance of PAHs containing two to four aromatic rings in most of the samples suggested the direct input of raw sewage into the
water resources evaluated. Benzo[g,h,i]perylene, dibenzo[a,h]anthracene and indeno[1,2,3-cd]pyrene were predominant in sediments
from the areas under the greatest urban and industrial development. The correlation between thermodynamic stability and the kinetics
of evolution presented by the isomeric pairs indicated that combustion is the predominant source of PAHs in the sediments because the
combustion of fossil fuels affected most of the points evaluated, followed by combustion of biomass and eventually combustion of oil
product inputs. In general, the results showed that areas under strong urban influence, as well as the Ira′? EPA, receive contributions of
PAHs from similar sources. 相似文献
309.
MIEX树脂可以有效去除水源中的UV254,UV254去除率与树脂的投加量和水源水质有关,新树脂的投加量大于10ml/L时,UV254的去除率为56%-83%。树脂在连续运行103次的过程中,仍然没有明显的UV254饱和穿透现象,树脂投加量5ml/L(20600BV),UV254去除率为45%~25%;树脂投加量15ml/L(6768BV),UV254的去除率为62%~40%。该树脂单位单次的最大UV254吸附量约为0.003cm^-1(UV254)/ml(树脂)·次。 相似文献
310.
Large, landscape-scale national monuments have long been controversial. It has been claimed that large monuments harm local economies by restricting growth of the grazing, timber, mining, and energy industries. Others have asserted that large monuments aid economic growth by reducing reliance on volatile commodity markets and fostering tourism growth. In this study, we use a synthetic control approach to measure the average causal effect of nine national monument designations on county-level per capita income. We find no evidence that monument designation affected per capita income in any of 20 counties hosting nine large (>50,000 acres) national monuments established under the Antiquities Act (six monuments) or by legislative action (three monuments). The broad economic claims of both advocates and critics of large national monuments have little empirical support. The absence of a designation effect for large national monuments is likely due to the attributes of federal land and the legal constraints under which it is managed. 相似文献