重庆市区2000年前大气环境质量的灰色预测

本文运用灰色系统理论,预测了重庆市区1990年至2000年的大气质量变化趋势。     

Cu2O光催化降解水中对硝基苯酚的研究

用CuCl水解法制备Cu2O粉末,用透射电镜(TEM)和X衍射(XRD)对Cu2O粒子进行了表征.在仿太阳光源的照射下,研究了Cu2O对水中难降解有机污染物对硝基苯酚的光催化降解效果.结果表明,在8 h内,对硝基苯酚几乎完全降解.在催化剂用量为0.2 g时,对浓度为22.4 mg/L的200mL对硝基苯酚溶液有良好的降解效果.降解反应符合一级反应动力学.     

参杂负载型纳米TiO2降解橙黄G的光催化活性及其动力学研究

采用溶胶-凝胶法和浸渍-焙烧法制备了掺杂Sn（Ⅳ）的TiO2／AC光催化剂，以偶氮染料橙黄G为目标降解物，对光催化反应条件进行了优化。结果表明：利用Sn（IV）掺杂量为2．5at．％的TiO2／AC光催化剂，在进水浓度50mg／L，催化剂的用量12．5g／i，pH值2．0，H2O2 1．5mL／L。主波长为365nm的300W高压汞灯光照条件下，反应60rain，橙黄G的光催化去除率可达99．1％。该反应符合Langmuir-Hinshelwood动力学方程，其速控步为吸附反应。共存阴离子SO4^2-和H2PO4^-，对橙黄G的光催化降解反应均有一定的抑制作用。     

掺杂负载型纳米TiO2降解橙黄G的光催化活性及其动力学研究

采用溶胶-凝胶法和浸渍-焙烧法制备了掺杂Sn(Ⅳ)的TiO2/AC光催化剂,以偶氮染料橙黄G为目标降解物,对光催化反应条件进行了优化.结果表明:利用Sn(Ⅳ)掺杂量为2.5 at.%的TiO2/AC光催化剂,在进水浓度50 mg/L,催化剂的用量12.5 g/L,pH值2.0,H2O21.5 mL/L,主波长为365 nm的300W高压汞灯光照条件下,反应60 min,橙黄G的光催化去除率可达99.1%.该反应符合Langmuir-Hinshelwood动力学方程,其速控步为吸附反应.共存阴离子SO42-和H2PO4-,对橙黄G的光催化降解反应均有一定的抑制作用.     

Spatial Pattern Analysis of Regional Water Use Profile Based on the Gini Coefficient and Location Quotient

Water resources have become a barrier hampering socioeconomic development. Changes in the spatial distribution of water use profile have direct impacts to regional water use efficiency. However, the related research is inadequate, and a more suitable way to analyze regional water use profile is necessary. The Gini coefficient and location quotient, two reliable methods commonly used in discussing the spatial distribution of elements, were introduced and calculated. Taking Gansu Province as the study area, the concentration effect of industrial water use was the strongest, followed by domestic, environmental, and agricultural water use. However, a balanced distribution of agricultural water use failed to be coordinated with the production conditions, the center of Gansu’s grain production should be established to enhance the scale effect of agricultural production. The industrial agglomeration effect remained weak, and each region’s dominant industries need to be developed vigorously. Gansu’s domestic water use was consistent with its population distribution, but it is necessary to reduce the water use gap between urban and rural areas. With a growing awareness of environmental protection, environmental water use exhibited a more balanced distribution. Overall, the methods are simple and have good applicability, and the results can provide a reference in water use optimization.     

Characterizing the antibiotic resistance genes in a river catchment: Influence of anthropogenic activities

Previous studies on environmental antibiotics resistance genes(ARGs) have focused on the pollution sources such as wastewater treatment plants, aquaculture and livestock farms,etc. Few of them had addressed this issue in a regional scale such as river catchment. Hence,the occurrence and abundances of 23 ARGs were investigated in surface water samples collected from 38 sites which located from the river source to estuary of the Beijiang River.Among them, 11 ARGs were frequently detected in this region and 5 ARGs(sul I, sul II, tet B,tet C, and tet W) were selected for their distribution pattern analysis. The abundances of the selected ARGs were higher in the upstream(8.70 × 10~6 copies/ng DNA) and downstream areas(3.17 × 10~6 copies/ng DNA) than those in the midstream areas(1.23 × 10~6 copies/ng DNA), which was positively correlated to the population density and number of pollution sources. Pollution sources of ARGs along the Beijiang River not only had a great impact on the abundances and diversity, but also on the distribution of specific ARGs in the water samples. Both sul I and sul II were likely originated from aquaculture farms and animal farms,tet W gene was possibly associated with the mining/metal melting industry and the electric waste disposal and tet C gene was commonly found in the area with multiple pollution sources.However, the abundance of tet B was not particularly related to anthropogenic impacts. These findings highlight the influence of pollution sources and density of population on the distribution and dissemination of ARGs at a regional scale.     

In‐well sediment incubators to evaluate microbial community stability and dynamics following bioimmobilization of uranium

An in‐well sediment incubator (ISI) was developed to investigate the stability and dynamics of sediment‐associated microbial communities to prevailing subsurface oxidizing or reducing conditions. Herein we describe the use of these devices at the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site. During a seven‐month period in which oxidized Rifle Aquifer background sediment (RABS) were deployed in previously biostimulated wells under iron‐reducing conditions, cell densities of known iron‐reducing bacteria, including Geobacteraceae, increased significantly, showing the microbial community response to local subsurface conditions. Phospholipid fatty acid (PLFA) profiles of RABS following in situ deployment were strikingly similar to those of adjacent sediment cores, suggesting ISI results could be extrapolated to the native material of the test plots. Results for ISI deployment with laboratory‐reduced sediments showed only slight changes in community composition and pointed toward the ability of the ISI to monitor microbial community stability and response to subsurface conditions. © 2009 Wiley Periodicals, Inc.     

北江流域抗生素污染水平和来源初探

北江是发源于湖南(武水)和江西(浈水),汇于广东韶关,流经广东全境并入海的三大河流之一。为了解整个北江抗生素污染情况,共设置44个采样点,并采集了河水及部分沉积物样品,较全面地分析了各样品中12种典型抗生素含量并初步探究了其污染来源。研究发现,包括北江源头在内的全河段均有抗生素的检出,5类抗生素在表层水和沉积物中的平均浓度分别为77.8 ng·L~(-1)和3.6 ng·g~(-1)。其中,大环内酯类污染最为严重,其含量范围为11.7~114.6 ng·L~(-1)和0~435.3 ng·g~(-1),远高于其他类抗生素。表层水中磺胺类的磺胺甲恶唑和氯霉素类的检出率达100%,其中以磺胺甲恶唑(14.7 ng·L~(-1))和阿奇霉素(25.0 ng·L~(-1))为主,而沉积物中以阿奇霉素(35.9 ng·g~(-1))、氧氟沙星(5.4 ng·g~(-1))和四环素(3.3 ng·g~(-1))为主。由于流域污染源种类和数量不同,各抗生素在北江中的分布也存在差异。表层水中抗生素含量水平表现为下游高于上中游,在沉积物中则主要集中于中、下游之间河段。这反映了人类活动强度对北江抗生素污染的直接影响。