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501.
As one of China’s great metropolises, Taiyuan is affected by heavy chemical industry and manufacture of chemical products, and faces pollution from polychlorinated biphenyls (PCBs). Therefore, this study was conducted to determine the PCB concentrations in various environmental media in Taiyuan. We collected 15 soil samples, 34 respirable particulate matter (PM) samples (17 of PM2.5 and 17 of PM10) from urban areas of Taiyuan, and measured a total of 144 PCB congeners (including some coeluting PCB congeners). The total PCB concentrations were 51–4.7 × 103 pg g−1 in soil, 27–1.4 × 102 pg m−3 in PM2.5 and 16–1.9 × 102 pg m−3 in PM10. Of the PCB homologues, the dominant PCBs detected in the various media were all tri-CBs. Soil was relatively the most polluted media. Furthermore, principal-component analysis revealed that the major PCB source in Taiyuan may be associated with the main commercial PCB through long-range transmission. Toxic equivalency (TEQ) concentrations (based on ten dioxin-like PCBs) ranged from N.D. to 5.9 × 10−3 pg-WHO TEQ g−1 in soil, 2.0 × 10−4–3.4 × 10−3 pg-WHO TEQ m−3 and 1.0 × 10−4–1.2 × 10−3 pg-WHO TEQ m−3 in PM2.5 and PM10, respectively. In previous studies, PCBs were not a severe component of contaminant in Taiyuan; however, this study suggested there is a potential threat of human exposure to PCBs for residents of Taiyuan. 相似文献
502.
Chaosheng Zhang Ya Tang Lin Luo Weilin Xu 《Environmental pollution (Barking, Essex : 1987)》2009,157(11):3083-3090
Outliers in urban soil geochemical databases may imply potential contaminated land. Different methodologies which can be easily implemented for the identification of global and spatial outliers were applied for Pb concentrations in urban soils of Galway City in Ireland. Due to its strongly skewed probability feature, a Box–Cox transformation was performed prior to further analyses. The graphic methods of histogram and box-and-whisker plot were effective in identification of global outliers at the original scale of the dataset. Spatial outliers could be identified by a local indicator of spatial association of local Moran's I, cross-validation of kriging, and a geographically weighted regression. The spatial locations of outliers were visualised using a geographical information system. Different methods showed generally consistent results, but differences existed. It is suggested that outliers identified by statistical methods should be confirmed and justified using scientific knowledge before they are properly dealt with. 相似文献
503.
认真落实科学发展观,以科学发展观统领工会工作,必须体现在党对工会工作的要求上,体现在准确全面履行好工会的职责上,从而充分发挥工会在支持改革开放、促进经济发展、推动社会进步中的积极作用。 相似文献
504.
微波无极紫外光催化-内电解协同降解活性艳红X-3B 总被引:5,自引:1,他引:4
采用微波无极紫外光源,以活性炭作为光催化剂TiO2的载体,与外加铁屑构成内电解反应,处理活性艳红X-3B模拟废水.实验结果表明,微波无极紫外光催化-内电解法对活性艳红X-3B的降解速率是微波无极紫外光催化和微波-内电解法单独作用时降解速率之和的2倍.在活性艳红X-3B模拟废水初始pH为7、空气曝气量为0.50 L/min、铁屑加入量为5 g/L、反应温度为40~45℃的最佳条件下,微波无极紫外光催化-内电解法的活性艳红X-3B模拟废水色度去除率达100%,TOC和可吸附有机卤化物的去除率分别为69.5%和81.8%. 相似文献
505.
NaCl和KCl对厌氧污泥抑制的动力学研究 总被引:2,自引:0,他引:2
在厌氧颗粒污泥和厌氧絮状污泥系统中,进行盐质量浓度(NaCl或KCl质量浓度,下同)对厌氧污泥抑制动力学的研究,得到不同拟合的COD降解动力学方程及参数.实验结果表明:当盐质量浓度为10~30 g/L时,KCl对厌氧污泥的COD比降解速率的抑制程度大于NaCl;当盐质量浓度由0 g/L增至10 g/L时,半速率常数逐渐增加;当盐质量浓度由10 g/L增至30 g/L时,半速率常数逐渐减小;在厌氧污泥系统中,NaCl抑制作用下的盐抑制常数高于KCl,且颗粒污泥的盐抑制常数高于絮状污泥. 相似文献
506.
507.
Naman Cissoko Zhen Zhang Jinghui Zhang Xinhua Xu 《Process Safety and Environmental Protection》2009,87(6):395-400
The Cr(VI) removal from simulative contaminated groundwater using zero-valent iron (Fe0) filings, Fe0 powder and nanoscale Fe0 in batch experimental mode was studied. Cr(VI) is a primary pollutant of some soils and groundwater. Zero-valent iron, an important natural reductant, could transform Cr(VI) to Cr(III) which is much less toxic and immobile. The Cr(VI) removal percentage was 87% at a metal to solution ratio of 6 g l−1 for commercial iron powder (200 mesh) in 120 min, and 100% Cr(VI) was removed when the metal to solution ratio was 10 g l−1. The results demonstrates that the Cr(VI) removal percentage was affected apparently by pH, the amount of Fe powder and the reaction temperature. The Cr(VI) removal percentage with nanoscale Fe0 was much higher than those with Fe0 filings or Fe0 powder at the same reaction time. Electrochemical analysis of the reaction process led to the conclusion that the Cr(VI) trended to form Cr(III) hydroxide under the reaction conditions. The kinetics analysis showed that Cr(VI) reduction by Fe0 could be described as a pseudo-first-order kinetics model. 相似文献
508.
爆炸物冲击波的人体防护研究 总被引:2,自引:0,他引:2
针对爆炸物爆炸冲击波、破片或子弹冲击、高温高压气体热辐射等复杂环境下的人体伤害威胁,本文从人员损伤研究和防护材料研究两方面综述了国内外研究进展,最后为开展人体有效防护研究工作提出了几点建议. 相似文献
509.
本文介绍了各类防毒服和防毒面具的发展历史、各国的研究情况,对装备的穿戴情况和时机作了简要的概括.最后对未来个人防护装备发展趋势进行展望,阐明了未来装备发展的重点和方向. 相似文献
510.
以延安新区黄土高填方工程中的上埋式排水管道为原型,开展了相似比为1:2的室内试验,试验前在模型箱底部一定位置预设沉降底板模拟实际填方的工后沉降过程,在试验土体和管道中布设压力盒、位移计和应变片,以采集试验过程中的管土接触压力、管-土相对位移和管道应变等数据。研究表明,负土拱效应对管道的上部压力影响明显,竖向压力系数最大达3.4,与沉降量的关系符合三次多项式曲线,负土拱效应对管道的影响不可忽略。开挖纵向剖面后发现管道下部土层间出现明显的脱空裂缝,是管道下部管-土接触压力减小的原因。该成果为黄土高填方场地中管周土压力的计算、管道变形控制提供参考。 相似文献