Polychlorinated biphenyls contamination in urban soil of Shanghai: level, compositional profiles and source identification

Surface soil samples taken from 55 sampling sites at the urban areas of Shanghai were collected and analyzed for the occurrence of 144 polychlorinated biphenyls (PCBs) by GC-μECD. The results showed that totally 74 PCB congeners were identified and the mean concentration of total PCBs was 3057 ng kg⁻¹ with a range of 232 to 11325 ng kg⁻¹. Compared with the related reports, the level of PCBs contamination in this study was approximately equal to the global background value in soils, but higher than Chinese background for rural and urban soils. According to the compositional profiles of PCBs homologues, a higher proportion of low chlorinated (from tri-CBs to hexa-CBs) was observed. The results indicated that PCB15 + 13, PCB18, PCB28, PCB104 + 47 and PCB153 were the most dominant congeners among the identified PCBs. Through homologues analysis, cluster analysis and principal component analysis (PCA), it was found that PCBs were stretched from mixed local sources, and appeared to be mostly originated by Aroclor 1260- and 1254-like mixtures as well as some samples influenced by Aroclor 1232 and 1242. The correlation analysis showed the relatively good correlation among the PCB homologues and soil total organic carbon (TOC), suggesting important influence of soil TOC on PCBs contamination in soil matrix in Shanghai region. The toxic equivalency (TEQ) concentrations of these six dioxin-like PCBs detected in urban soil samples range from 2.71 to 24.9 pg kg⁻¹-PCDDeq with a mean 8.18 pg kg⁻¹-PCDDeq.     

中央空调节能减排技术改造——实例探析

通过实施中央空调系统全方位节能减排技术,优化电网安全用电,节省电费开支,减少建设成本。不仅可收到可观的经济效益,而且能取得良好的社会效益,是我国建设资源节约型、环境友好型社会的必然要求。节能减排,减少污染,应立足本职．把节能减排工作抓紧抓好,推而广之。     

基于GIS的城市生命线工程地震反应仿真研究——以上海市供水系统为例

探讨了地理信息系统（GIS）在城市生命线地震反应仿真研究中的应用,以上海市内环中心城区为背景,以供水系统为例,运用网络可靠性分析法进行了给水管网的震害预测,在此基础上以GIS功能强大的软件ArcView为开发平台,创建了可视化的上海市水管网地震反应仿真真信息系统。     

中亚五国气溶胶光学厚度时空分布特征研究

气溶胶时空变化是影响气溶胶气候效应不确定性的主要因素之一.在生态环境脆弱的中亚五国(哈萨克斯坦、乌兹别克斯坦、土库曼斯坦、吉尔吉斯斯坦和塔吉克斯坦)研究气溶胶光学厚度(Aerosol Optical Depth,AOD)的时空变化对中亚地区及全球生态环境和气候变化具有重要意义.基于2002-2019年MODIS 04_...     

2010—2016年上海城区臭氧长时间序列变化特征初探

基于2010—2016年上海城区近地面大气臭氧（O₃）的连续在线观测数据，研究了上海城区O₃长时间序列变化规律和污染特征.结果表明，近7年来上海城区O₃污染逐渐凸显，但总体以轻度污染为主，7—8月高温炎热季节以中度污染居多.城区O₃-8 h（臭氧日最大8 h滑动平均）年均增速为3.81 μg·m^-3·a^-1，99%和95%分位值增速较快，分别为6.65和4.94 μg·m^-3·a^-1；25%、50%和75%分位值的增速在3.06~4.45 μg·m^-3·a^-1之间.春季O₃浓度均值较高，年际变化小；夏季极值较高，且污染超标情况最为突出；秋季O₃浓度次于春、夏季，冬季最低；夏、秋和冬季O₃浓度总体呈上升态势.O₃日变化呈"单峰型"，最大值出现在13：00左右，且峰值逐年增加，污染持续时间变长，最小值出现在早晨7：00.城区O₃"周末效应"逐渐减弱.基于KZ过滤器方法的数据分析结果表明，上海城区O₃-8 h长期变化主要受O₃-BF（O₃-8 h的基准组分）影响；O₃-SF（O₃-8 h的天气影响组分）在5—9月对O₃-8 h影响较大，其范围为-98.85~139.60 μg·m^-3.