Modelling the effects of water diversion and combined sewer overflow on urban inland river quality

In order to assist and optimize the operation of a clean water diversion project for the medium-sized inland rivers in Chaohu, China, an integrated hydrodynamic and water quality model was used in this study. Sixteen diversion scenarios and five sewage interception scenarios were defined to assess the improvement of water quality parameters including ammonia nitrogen (NH₃-N), total phosphorus (TP) and chemical oxygen demand (COD) under different diverted water flows, diverting times, diverting points, diverting routines and sewage interception proportions. An index of pollutant removal rate per unit diverted water flow (PRUWF) was proposed to evaluate the effect of the clean water diversion. Results show that operating conditions played important roles in water quality improvement of medium-sized inland rivers. The optimal clean water diversion was operated under the conditions of a flow rate of 5 m³/s for 48 h with an additional constructed bridge sluice. A global sensitivity analysis using the Latin Hypercube One-Factor-at-a-Time (LH-OAT) method was conducted to distinguish the contributions of various driving forces to inland river water restoration. Results show that sewage interception was more important than diverted water flow and diverting time with respect to water quality improvement, especially for COD.     

Effects of organic acids on the photosynthetic and antioxidant properties and accumulations of heavy metals of <Emphasis Type="Italic">Melilotus officinalis</Emphasis> grown in Cu tailing

The effect of citric acid (CA), acetic acid (Ac), and ethylene diamine tetraacetic acid (EDTA) on the photosynthetic and antioxidant properties and the accumulation of some heavy metals (HMs) of Melilotus officinalis seedling growing in Cu mine tailings for 25 days were studied. Results showed that the formation of photosynthesizing cells of M. officinalis was inhibited by EDTA at 2 mmol/kg. Photosynthetic pigment contents under EDTA of 2 mmol/kg were reduced by 26, 40, and 19 %, respectively, compared to the control. The proline contents in aboveground and underground parts increased as the level of EDTA was enhanced. CA and Ac enhanced the activities of superoxide dismutase (SOD) and peroxidase (POD) in the aboveground parts and EDTA inhibited the activity of POD in the underground parts. The addition of CA promoted significantly the growth of M. officinalis, while the biomass decreased significantly under 2 mmol/kg EDTA. Cu contents in the aboveground parts treated with 0.5 and 2.0 mmol/kg EDTA reached 175.50 and 265.17 μg/g dry weight, respectively. Ac and EDTA treatments promoted Cd to translocate from root to aboveground parts. The result indicated that M. officinalis was a tolerant species of Cu tailing and can be used to remediate Cu contaminated environment, and rationally utilization of organic acids, especially EDTA, in the phytoremediation can improve the growth and metals accumulation of M. officinalis.     

BTEX exposures in an area impacted by industrial and mobile sources: Source attribution and impact of averaging time

The impacts of emissions plumes from major industrial sources on black carbon (BC) and BTEX (benzene, toluene, ethyl benzene, xylene isomers) exposures in communities located >10 km from the industrial source areas were identified with a combination of stationary measurements, source identification using positive matrix factorization (PMF), and dispersion modeling. The industrial emissions create multihour plume events of BC and BTEX at the measurement sites. PMF source apportionment, along with wind patterns, indicates that the observed pollutant plumes are the result of transport of industrial emissions under conditions of low boundary layer height. PMF indicates that industrial emissions contribute >50% of outdoor exposures of BC and BTEX species at the receptor sites. Dispersion modeling of BTEX emissions from known industrial sources predicts numerous overnight plumes and overall qualitative agreement with PMF analysis, but predicts industrial impacts at the measurement sites a factor of 10 lower than PMF. Nonetheless, exposures associated with pollutant plumes occur mostly at night, when residents are expected to be home but are perhaps unaware of the elevated exposure. Averaging data samples over long times typical of public health interventions (e.g., weekly or biweekly passive sampling) misapportions the exposure, reducing the impact of industrial plumes at the expense of traffic emissions, because the longer samples cannot resolve subdaily plumes. Suggestions are made for ways for future distributed pollutant mapping or intervention studies to incorporate high time resolution tools to better understand the potential impacts of industrial plumes.

Implications: Emissions from industrial or other stationary sources can dominate air toxics exposures in communities both near the source and in downwind areas in the form of multihour plume events. Common measurement strategies that use highly aggregated samples, such as weekly or biweekly averages, are insensitive to such plume events and can lead to significant under apportionment of exposures from these sources.     

Atmospheric pollution in an urban environment by tree bark biomonitoring - part II: Sr, Nd and Pb isotopic tracing

The harmful effect of manmade particles on natural processes and human health is documented by a large number of studies showing a positive correlation between particulate matter (PM) concentration and health effects. Diminution of this health risk necessitates among others the precise knowledge of the particle sources, their physical and chemical properties and their dissemination in the environment. Pb isotope ratios have been successfully used during the past decades as tracers of anthropogenic Pb disseminated in the biosphere. Here we show that tree bark biomonitoring with lead (Pb), strontium (Sr) and neodymium (Nd) isotope ratios as tracers allow a thorough analysis of the impacts of industrial and other anthropogenic emissions on the urban environment. This is the first comprehensive multi-isotope tracer study of atmospheric pollution in an urban environment allowing to identify and to integrate the different plume paths of emissions in a digital map system. This innovative approach might become an important tool for environmental management and policy-making processes dealing especially with risks and surveillance of air quality in the urban environment.     

Examination of Resource Curse Hypothesis: Mineral Resources Exploitation and Economic Growth in Xinjiang Autonomous Region

The mineral resources exploitation stage and the economic growth rate are various in different regions of Xinjiang Autonomous region. Using the method of location quotient, this paper identifies and classifies the intensive regions of three types of mineral resources, known as coal, oil and natural gas, respectively. The intensive regions of economic growth were also identified, according to the rate of per capita GDP growth at prefecture, autonomous prefecture and city. The relationships between different mineral resources and economic growth are different, for example, the relationship between economic growth and coal resource is positive, while the relationship between economic growth and oil resource, or natural gas resource is negative. This study empirically examines the effects of natural resources on economic growth of Xinjiang. The results show that whilst natural resources have a positive impact on growth, and can make a negative impact on growth through the transmission channels, such as investment, manufacture, human capital, and scientific and technologic innovation. Moreover, it studies the transmission channels, that is, the effect of natural resources on the other explanatory variables, and calculates the indirect effect of natural resources on growth for each transmission channel, and comprehensive effects of natural resources on growth. The calculated result of comprehensive effects indicates that the positive direct effects of natural resources on growth are shown to outweigh the negative indirect effect of Xinjiang autonomous region.     

浸出毒性鉴别重金属分析中存在的问题

浸出毒性鉴别是判定危险废物的依据之一,在固体废物管理中具有极重要的意义。但实际浸出毒性鉴别分析工作尚属于起步阶段,还存在诸多问题和难点,需要从各方面加强固体废物浸出毒性鉴别技术方面的研究,不断完善鉴别能力,使浸出毒性鉴别结果更加准确可靠。     

生活污水中蛋白质测试方法研究

分别用Folin-酚改进法、考马斯亮兰法和紫外分光光度法等3种测试方法测试了上海市某小区生活污水中的蛋白质含量,对这3种测试方法进行了比较,并采用氨基酸仪分析了生活污水中蛋白质水解后的氨基酸化学组成.试验结果表明,Folin-酚改进法测试蛋白质浓度的准确性与精确性优于考马斯亮兰法和紫外分光光度法,可用于测定生活污水中蛋白质的浓度;氨基酸仪法测得该生活污水中含有17种氨基酸,其中最多的为谷氨酸(3.6 mg/L),含量最低的是脯氨酸(0.8 mg/L);所测生活污水中蛋白质COD占总COD的18.9%.     

蒸汽排放降噪式污水回收装置研究及应用

注汽锅炉是稠油油田热注作业生产使用的主要设备,当需要停止注汽或需要维修时,需将炉内的高温高压蒸汽进行排空,才能保证安全作业;而高压蒸汽直接进行排空时,会产生120 dB(A)以上的强烈的噪声污染,针对此问题曙光油田研制了"蒸汽排放降噪式污水回收装置"。文章介绍了其降噪及污水回收原理,对其现场应用情况进行了说明。实际应用效果表明,该装置可以达到降噪、节水、减排多重作用。     

Differences in uptake and translocation of selenate and selenite by the weeping willow and hybrid willow

BACKGROUND, AIM, AND SCOPE: Due to its essentiality, deficiency, and toxicity to living organisms and the extensive use in industrial activities, selenium (Se) has become an element of global environmental and health concern. Se removal from contaminated sites using physical, chemical, and engineering techniques is quite complicated and expensive. The goal of this study was to investigate uptake and translocation of Se in willows and to provide quantitative information for field application whether Se phytoremediation is feasible and ecologically safe. MATERIALS AND METHODS: Intact pre-rooted plants of hybrid willows (Salix matsudana Koidz x alba L.) and weeping willows (Salix babylonica L.) were grown hydroponically and treated with selenite or selenate at 24.0 +/- 1 degrees C for 144 h. Removal of leaves was also performed as a treatment to quantify the effect of transpiration on translocation and volatilization of Se. At the end of the study, total Se in the hydroponic solution and in different parts of plant tissues was analyzed quantitatively by hydride generation-atomic fluorescence spectrometry. The capacity of willows to assimilate both chemical forms of Se was also evaluated using detached leaves and roots in sealed glass vessels in vivo. Translocation efficiency of Se in both plants was estimated. RESULTS: Significant amounts of the applied selenite and selenate were eliminated from plant growth media by willows during the period of incubation. Both willows showed a significantly higher removal rate for selenate than for selenite (p < 0.05). Substantial differences existed in the distribution of both chemical forms of Se in plant materials: lower stems and roots were the major sites for accumulation of selenite and selenate, respectively. Translocation efficiency for selenite was significantly higher than that for selenate in both willow species (p < 0.01). Compared to the intact trees, remarkable decrease in the removal rate of both chemical forms of Se was found for willows without any leaves (p < 0.01). Volatilization of Se by plant leaves was estimated to be approximately 10% of the total applied selenite or selenate. Significant reduction (>20%) of selenate was observed in the sealed vessel with excised roots of willows, whereas trace amounts of selenite were eliminated from the hydroponic solution in the presence of roots. Detached leaves from neither of them reduced the concentration of selenite or selenate in the solution. DISCUSSION: Due to the significant difference in the removal rate and the distribution of the two chemical forms of Se in plant materials, the conversion of selenate to selenite in hydroponic solution prior to uptake and within plant tissues is unlikely. An independent uptake and translocation mechanisms are likely to exist for each Se chemical species. Uptake of selenate is mediated possibly through an active transport mechanism, whereas that of selenite may possibly depend on plant transpiration. Uptake velocities of selenite are linear (zero-order kinetics), while selenate removal processes obey first-order kinetics. In experiments with detached leaves in closed bottles, the cuticle of leaves was the major obstacle to extract both chemical forms of Se from the hydroponic solution. Phytovolatilization is a biological process playing an important role in Se removal. CONCLUSIONS: Although faster removal rates of selenate than selenite from plant growth media were observed by both willow species, selenite in plant materials was more mobile than selenate. Significant decrease in removal rates of both chemical forms of Se was detected for willows without any leaves. Significant differences in extraction, assimilation and transport pathways for selenite and selenate exist in willow trees. RECOMMENDATIONS AND PERSPECTIVES: Phytoremediation of Se is an attractive approach of cleaning up Se contaminated environmental sites. More detailed investigation on the assimilation of Se in plant roots and transport in tissues will provide further biochemical evidence to explain the differences in uptake and translocation mechanisms between selenite and selenate in willows. A relevant phytoremediation scheme can then be designed to clean up Se contaminated sites. Willows show a great potential for uptake, assimilation and translocation of both selenite and selenate. Phytotreatment of Se is potentially an efficient and practical technology for cleaning up contaminated environmental sites.     

光催化三维蜂窝陶瓷网净化室内空气的研究

先制备钛酸溶胶和掺杂Fe3 的钛酸溶胶,用溶胶-凝胶法分别将其负载于具有一定厚度的矩形蜂窝陶瓷三维网载体上,再用程序升温法煅烧.得到复合纳米TiO2光催化三维蜂窝陶瓷网.经扫描电镜(SEM)测定,三维蜂窝陶瓷网体上负载膜的厚度为300～400 nm,TiO2的粒径为15～20 nm.将光催化三维蜂窝陶瓷网置于光处理箱体内,在紫外光强、循环风量一定的条件下,对容积为72.6 m3和81.4 m3房间进行空气净化.结果表明,无论掺Fe3 与否的TiO2光催化三维蜂窝陶瓷网都有净化效果,其中以掺Fe3 的效果最好:当甲醛起始浓度为0.404 mg/m3,18 h的去除率为99.5%;当起始细菌总数为924 cfu/m3,24 h后的灭菌率为99.5%.