基于贝叶斯网络的危化品爆炸事故电力系统风险评估模型

为提高危化品爆炸事故电力应急预警的准确性,建立基于贝叶斯网络的危化品爆炸事故电力系统风险评估模型.基于危化品爆炸事故电力应急典型情景分析,建立综合考虑突发事件、承灾载体和应急管理等风险因素的贝叶斯网络结构.应用概率刻画风险因素信息的不确定性及其相互影响,定量分析事件后果.结合一般条件和典型情景等的应用实例,分析评价方法...     

The temporal changes in road stormwater runoff quality and the implications to first flush control in Chongqing, China

This study investigates the quality of stormwater runoff from a driveway in the southwest mountainous urban area of Chongqing, China, from 2010 to 2011. The results showed that the mean concentrations of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) were 4.1, 2.4, and 2.2 times the grade V levels of the national surface water standard of China. The pollutant concentration peak preceded or synchronized with the rainfall intensity peak and occurred 10 min after the runoff started. The significant high pollutant concentration in the initial stage of the rainfall suggested that first flush control is necessary, especially for the most polluted constitutes, such as total suspended solids, COD, and TN. Three potential pollution sources were identified: the atmospheric dry and wet deposition (TN, NO₃ ^?-N, NH₄ ⁺-N, and DCu), the road sediment and materials (total suspended solids, COD, and TP), and the vehicle emissions (DPb and DZn). Therefore, this study indicates that reductions in road sediments and material pollution and dry and wet deposition should be the priority factors for pollution control of road stormwater runoff in mountainous urban areas.     

Pyrimethanil residue and dissipation in tomatoes and soil under field conditions

A residue analytical method to detect pyrimethanil in tomatoes and soil was developed by using high-performance liquid chromatography with a diode array detector. The dissipation and residue level of pyrimethanil in tomatoes and soil were also investigated. Results showed that the average recoveries are in the range of 87.2 to 90.0 % with a relative standard difference of 2.22 to 7.61 % in tomatoes and soil. In Guangdong, Shandong, and Yunnan, the half-lives of pyrimethanil in tomatoes were 1.8, 3.6, and 4.2 days and those in soil were 4.0, 3.3, and 3.9 days, respectively. The dissipation rate of pyrimethanil in tomatoes and soil was affected by temperature, precipitation, and soil type. The terminal residue results showed that when pesticide pyrimethanil was used under the experiment design, all the results were far below the available maximum residue limits. Low residues in tomatoes and soil suggest that this pesticide is safe to use under the recommended dosage.     

关于水污染物总量控制研究进展及问题分析

水污染物浓度控制和排放总量控制是水质达标管理的前提。本文将其和水污染物的总量控制发展进程相互结合,对实施应用和理论完善以及深入探讨等阶段的进展进行阐述,介绍污染物总量控制实施时的总量分配和入河控制等相关技术细节,得到总量控制的实施优点,最后明确控制污染物总量的具体意义。     

Review on remediation technologies for arsenic-contaminated soil

• Recent progress of As-contaminated soil remediation technologies is presented. • Phytoextraction and chemical immobilization are the most widely used methods. • Novel remediation technologies for As-contaminated soil are still urgently needed. • Methods for evaluating soil remediation efficiency are lacking. • Future research directions for As-contaminated soil remediation are proposed. Arsenic (As) is a top human carcinogen widely distributed in the environment. As-contaminated soil exists worldwide and poses a threat on human health through water/food consumption, inhalation, or skin contact. More than 200 million people are exposed to excessive As concentration through direct or indirect exposure to contaminated soil. Therefore, affordable and efficient technologies that control risks caused by excess As in soil must be developed. The presently available methods can be classified as chemical, physical, and biological. Combined utilization of multiple technologies is also common to improve remediation efficiency. This review presents the research progress on different remediation technologies for As-contaminated soil. For chemical methods, common soil washing or immobilization agents were summarized. Physical technologies were mainly discussed from the field scale. Phytoextraction, the most widely used technology for As-contaminated soil in China, was the main focus for bioremediation. Method development for evaluating soil remediation efficiency was also summarized. Further research directions were proposed based on literature analysis.     

纳滤膜处理核苷酸生产中的碱盐废水

采用纳滤膜处理核苷酸生产中树脂再生工段的碱盐废水,研究了操作压力和废水温度等对膜性能的影响。实验结果表明,适宜的膜操作压力为1.5M Pa,废水温度对碱盐透过率及COD去除率均无明显影响。在室温、1.5M Pa条件下,COD的平均去除率大于98%,碱盐平均透过率大于97%,平均膜通量大于30.0L/(m2.h)。使用后的纳滤膜经质量分数为2%的柠檬酸溶液清洗后,膜通量完全能恢复到实验前的水平。透膜碱盐溶液可直接回到树脂再生工段。     

Evaluating sewage-associated JCV and BKV polyomaviruses for sourcing human fecal pollution in a coastal river in Southeast Queensland, Australia

In this study, the host-sensitivity and host-specificity of JC virus (JCV) and BK virus (BKV) polyomaviruses were evaluated by testing wastewater and fecal samples from nine host groups in Southeast Queensland, Australia. The JCV and BKV polyomaviruses were detected in 63 human wastewater samples collected from primary and secondary effluent, suggesting high sensitivity of these viruses in human wastewater. In the 81 animal wastewater and fecal samples tested, 80 were polymerase chain reaction (PCR) negative for the JCV and BKV markers. Only one sample (out of 81 animal wastewater and fecal samples) from pig wastewater was positive. Nonetheless, the overall host-specificity of these viruses to differentiate between human and animal wastewater and fecal samples was 0.99. To our knowledge, this is the first study in Australia that reports on the high specificity of JCV and BKV polyomaviruses. To evaluate the field application of these viral markers for detecting human fecal pollution, 20 environmental samples were collected from a coastal river. In the 20 samples tested, 15% (3/20) and 70% (14/20) samples exceeded the regulatory guidelines for Escherichia coli and enterococci levels for marine waters. In all, five (25%) samples were PCR positive for JCV and BKV, indicating the presence of human fecal pollution in the coastal river investigated. The results suggest that JCV and BKV detection using PCR could be a useful tool for identifying human-sourced fecal pollution in coastal waters.     

Linking river, floodplain, and vadose zone hydrology to improve restoration of a coastal river affected by saltwater intrusion

Floodplain forests provide unique ecological structure and function, which are often degraded or lost when watershed hydrology is modified. Restoration of damaged ecosystems requires an understanding of surface water, groundwater, and vadose (unsaturated) zone hydrology in the floodplain. Soil moisture and porewater salinity are of particular importance for seed germination and seedling survival in systems affected by saltwater intrusion but are difficult to monitor and often overlooked. This study contributes to the understanding of floodplain hydrology in one of the last bald cypress [Taxodium distichum (L.) Rich.] floodplain swamps in southeast Florida. We investigated soil moisture and porewater salinity dynamics in the floodplain of the Loxahatchee River, where reduced freshwater flow has led to saltwater intrusion and a transition to salt-tolerant, mangrove-dominated communities. Twenty-four dielectric probes measuring soil moisture and porewater salinity every 30 min were installed along two transects-one in an upstream, freshwater location and one in a downstream tidal area. Complemented by surface water, groundwater, and meteorological data, these unique 4-yr datasets quantified the spatial variability and temporal dynamics of vadose zone hydrology. Results showed that soil moisture can be closely predicted based on river stage and topographic elevation (overall Nash-Sutcliffe coefficient of efficiency = 0.83). Porewater salinity rarely exceeded tolerance thresholds (0.3125 S m(-1)) for bald cypress upstream but did so in some downstream areas. This provided an explanation for observed vegetation changes that both surface water and groundwater salinity failed to explain. The results offer a methodological and analytical framework for floodplain monitoring in locations where restoration success depends on vadose zone hydrology and provide relationships for evaluating proposed restoration and management scenarios for the Loxahatchee River.     

株洲高新区国家生态工业园区建设规划研究

株洲高新区以长株潭(长沙市、株洲市、湘潭市)两型社会示范建设为契机,规划建设以低碳经济为主体产业的国家生态工业示范园区。株洲高新区在有色金属深加工、先进制造等行业的科研创新体系日趋完善,且产业集群初具规模,已具备了创建国家生态工业示范园区的有利条件。通过国家生态工业示范园区创建工作,将进一步优化区域产业结构,推动产业联动发展。园区建设总体上分为产业循环体系、污染控制体系和保障体系三部分。     

Hydrous ferric oxide nanoparticles hosted porous polyethersulfone adsorptive membrane: chromium (VI) adsorptive studies and its applicability for water/wastewater treatment

In this present study, adsorptive membranes for Cr(VI) ion removal were prepared by blending polyethersulfone (PES) with hydrous ferric oxide (HFO) nanoparticles (NPs). The effects of HFO NPs to PES weight ratio (0–1.5) on the physicochemical properties of the resultant HFO/PES adsorptive membranes were investigated with respect to the surface chemistry and roughness as well as structural morphologies using different analytical instruments. The adsorptive performance of the HFO NPs/PES membranes was studied via batch adsorption experiments under various conditions by varying solution pH, initial concentration of Cr(VI), and contact time. The results showed that the membrane made of HFO/PES at a weight ratio of 1.0 exhibited the highest adsorption capacity which is 13.5 mg/g. Isotherm and kinetic studies revealed that the mechanism is best fitted to the Langmuir model and pseudo-second-order model. For filtration of Cr(VI), the best promising membranes showed improved water flux (629.3 L/m² h) with Cr(VI) ion removal of 75%. More importantly, the newly developed membrane maintained the Cr(VI) concentration below the maximum contamination level (MCL) for up to 9 h.