大气降水中重金属离子特征研究

大气降水中重金属离子的研究可以反映大气污染、地表水污染的信息.通过对国内外大气降水中重金属研究现状的阐述和大气降水中重金属的来源进行理论分析,并利用实地大气降水采样分析,归纳出其中重金属的特征,监测当前大气的污染状况,从而为区域性的大气中重金属的污染评价及污染治理提供理论依据.降水中的重金属元素主要包括Pb、Mn、Zn、Cu、Cd、Cr等,通过分析测定可以为利用大气降水作为重要饮用水补给源的区域提供饮水安全保障.     

保护地球环境

1972年联合国在瑞典的斯德哥尔摩召开了有113个国家参加的联合国人类环境会议。会议讨论了保护全球环境的行动计划,通过了《人类环境宣言》。会议建议联合国大会将这次会议开幕的6月5日定为“世界环境保护日”。同年10月联合国大会第27届会议接受并通过了这一建议。每年的6月5日,世界各国都开展群众性的环境保护宣传纪念活动,以唤起全世界人民都来注意保护人类赖以生存的环境,自觉采取行动参与环境保护的共同努力,同时要求各国政府和联合国系统为推进环境保护进程做出贡献。     

历史上的灾难年2007

2007年是历史上的灾难年。由于受全球气候变暖影响,我国多个省市发生了各种自然灾害,如干旱、洪水、泥石流、滑坡、飓风等,尤其是洪涝灾害,经济损失惨重。另有朝鲜、缅甸以及南亚的印度、孟加拉国、尼泊尔也成了一片泽国;就连美国也未幸免于洪灾。现简述如下。     

胜利油田含油污泥的植物修复研究

胜利油田滨一污水站产生的含油污泥经俄罗斯菌剂修复后含油量仍较高,为进一步降低其含油量,采用了植物修复技术.在总面积为1 000 m2的含油污泥修复场地上,分别种植了高羊茅、苜蓿、大豆、玉米和高粱,进行了120 d的植物修复.检测了植物修复前后含油污泥的含油量、基本理化性质、生物毒性、微生物数量和代谢功能多样性.对比发现,植物修复后含油污泥的石油降解率最高可达34.09%,持水率提高,生物毒性下降,微生物数量增加及代谢功能多样性增强.实验说明,植物修复是处理含油污泥的有效方法之一.     

用褐铁矿制备聚硅氯化硫酸铁的研究

通过正交实验研究了用盐酸、硫酸、褐铁矿和硅酸钠制备聚硅氯化硫酸铁（PSFCS）絮凝剂的工艺条件。实验结果表明,浸取时间为2.5～3 h,浸取温度为110℃,硫酸浓度为6 mol/L,盐酸浓度为3 mol/L,质量液固比为4∶1,铁的浸出率可达95.7%～96.3%。溶液中加入少量聚乙烯醇作稳定剂,亚硝酸钠作氧化催化剂。PSFCS的合成条件：Fe/Si摩尔比为2,硅酸活化pH值为2,硅酸活化时间是30～40 min,陈化时间是2～2.5 h。与聚合硫酸铁（PFS）和聚合氯化铝（PAC）比较了处理印染废水的效果,表明PSFCS具有良好的絮凝性能,COD和浊度的去除率分别可达81.4%和96.1%。     

Sorption of polar and nonpolar aromatic compounds to four surface soils of eastern China

Improved predictions on the fate of organic pollutants in surface environments require a better understanding of the underlying sorption mechanisms that control their uptake by soils. In this study, we monitored sorption of nine aromatic compounds with varying physicochemical properties (hydrophobicity, electron-donor/acceptor ability and polarity), including two polycyclic aromatic hydrocarbons, two chlorobenzenes, two nitroaromatic compounds, dichlobenil, carbaryl and 2,4-dichlorophenol in aqueous suspension of four surface soils of eastern China. The tested soils were characterized with respect to organic carbon (OC) content, black carbon content, mineralogy, morphology and size fraction to assess the role of the diverse soil characteristics in sorption. The results of this study show that not only the solute hydrophobicity and the OC content of soil are important to the retention of organic pollutants, but also the solute molecular structure and the soil nature.     

真空紫外光降解苯的研究

为了考察真空紫外光辐射在气体净化中的应用,以苯作为目标污染物,分别进行了紫外光波长、气体湿度、反应时间、初始浓度以及辐射功率对苯光解率的影响实验。实验结果表明,真空紫外光辐射方法净化气相污染物中的苯效果良好,在一定条件下,浓度为348.2 mg/m³苯污染气体真空紫外光降解率可达到90%。通过在不同条件下苯的降解率以及臭氧浓度变化,初步探讨了苯降解的机理以及降解途径。苯的降解主要是通过氢氧自由基（·OH）的加成以及后续一系列的氧化反应,降解产物为苯酚以及含有羟基的长链烃。     

Spatial and temporal variations and possible sources of dichlorodiphenyltrichloroethane (DDT) and its metabolites in rivers in Tianjin, China

Water, suspended solid (SS) and sediment samples were collected from nine water courses in Tianjin, China and analyzed for dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs, including o,p'-,p,p'-DDT, DDD and DDE). The average DDX concentrations in water, SS and sediment were 59+/-30 ng l(-1), 2690+/-1940 ng g(-1)dry wt. and 340+/-930 ng g(-1)dry wt., respectively. Due to the termination of the extensive agricultural application and industrial manufacture, DDXs in river sediment decreased by one order of magnitude since 1970's and low DDT fractions in these sediments were observed. Still, DDXs in the sediments near the outlets of the major manufacturers remained relatively high attributed to the historic input. DDXs in sediment were also positively correlated with organic matter content. Spatial distributions of DDXs in SS and water was different from that in sediment. For SS, a negative correlation between DDX concentration and SS content indicated a dilution effect in many rivers. Dissolved organic carbon content was the major factor affecting DDX concentrations in water phase. Wastewater discharged from dicofol manufacturers and likely illegal agricultural application were the primary reasons causing high DDT (DDE+DDD) ratios in SS and water.     

Source analysis of particulate-phase polycyclic aromatic hydrocarbons in an urban atmosphere of a northern city in China

Particle-associated polycyclic aromatic hydrocarbon (PAH) concentrations were investigated at six sampling sites in the heating (February to March 2001) and nonheating (August to September 2001) periods in an industrial city in Northern China. Thirteen PAHs were measured. The total average concentrations (nanograms per meter cubed) of PAHs ranged between 78.93 and 214.63 during the heating period and from 31.48 to 102.26 in the nonheating period. Benzo(a)pyrene occurred at the highest level at a site near an industrial area but occurred at low concentrations far from the city center and industrial areas. In addition, ambient PAH profiles were studied. The five and six-ring species occurred in high fractions at the sampling site. By diagnostic ratio analysis, the major source at each sampling site in the city was coal combustion in the heating period; in the nonheating period, the major sources were relatively complex. Finally, the similarities among the six regions were assessed by principal component analysis, cluster analysis, and coefficient of divergence. These multivariate statistical analyses produced similar results, which agreed with the results from the diagnostic ratio analysis.     

Application of artificial neural network approach and remotely sensed imagery for regional eco-environmental quality evaluation

Eco-environment quality evaluation is an important research theme in environment management. In the present study, Fuzhou city in China was selected as a study area and a limited number of 222 sampling field sites were first investigated in situ with the help of a GPS device. Every sampling site was assessed by ecological experts and given an Eco-environment Background Value (EBV) based on a scoring and ranking system. The higher the EBV, the better the ecological environmental quality. Then, three types of eco-environmental attributes that are physically-based and easily-quantifiable at a grid level were extracted: (1) remote sensing derived attributes (vegetation index, wetness index, soil brightness index, surface land temperature index), (2) meteorological attributes (annual temperature and annual precipitation), and (3) terrain attribute (elevation). A Back Propagation (BP) Artificial Neural Network (ANN) model was proposed for the EBV validation and prediction. A three-layer BP ANN model was designed to automatically learn the internal relationship using a training set of known EBV and eco-environmental attributes, followed by the application of the model for predicting EBV values across the whole study area. It was found that the performance of the BP ANN model was satisfactory and capable of an overall prediction accuracy of 82.4%, with a Kappa coefficient of 0.801 in the validation. The evaluation results showed that the eco-environmental quality of Fuzhou city is considered as satisfactory. Through analyzing the spatial correlation between the eco-environmental quality and land uses, it was found that the best eco-environmental areas were related to forest lands, whereas the urban area had the relatively worst eco-environmental quality. Human activities are still considered as a major impact on the eco-environmental quality in this area.