Organochlorine pesticides and PCBs in fish from lakes of the Tibetan Plateau and the implications

High mountains may play significant roles in the global transport of persistent organic pollutants (POPs). This work aims to investigate the levels, patterns and distribution of semi-volatile organoclorine pollutants and to improve the understanding of the long-range atmospheric transport and fate of contaminants on the Tibetan Plateau. A total of 60 fish samples were collected from eight lakes located between 2813 and 4718 m above sea level across the Plateau. Concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) including dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) were measured in fish muscle. The results showed that concentrations of DDT, HCH and HCB were comparable to or lower than those found in remote mountains of Europe, Canada and US, while PCB concentrations in fish were, on average, about 4-150 times lower on Tibet than at other mountain areas. The transport and fate of contaminants in the Plateau are significantly influenced by the unique climatological and meteorological conditions, particularly by the summer Indian monsoon and winter westerly jet stream.     

Plant species richness of riverbed elevations—the Pripyat river valley case study

Flora of the still unchanged or slightly modified floodplains is particularly valuable. Such are the natural, periodically flooded riparian ecosystems within the Mid-Pripyat river valley in Belarus. Distinctive elements of that area are ‘periodic islands’, which arise from the most elevated parts of the riverbed during flooding and have a specific microtopography. The aim of the research was to recognize floristic composition and ecological conditions of the ‘islands.’ Noted plants were mainly photophilous, by clearly varied in soil moisture, acidity and fertility requirements.     

颗粒化序列间歇式活性污泥反应器工艺处理化粪池污水

在序列间歇式活性污泥反应器(SBR)中成功培养出适应化粪池污水水质的好氧颗粒污泥.并将其应用于化粪池污水的处理.在好氧颗粒污泥培养的第15天左右,SBR中开始出现细小的颗粒,然后微生物在其上繁殖生长使颗粒逐渐增大而成熟;在第24天时,SBR中絮状活性污泥已基本实现了颗粒化.培养出的好氧颗粒污泥对化粪池污水有稳定的处理效果,在进水完全为化粪池污水时,COD、NH_4~+-N、TN的平均去除率分别为77%、61%、47%.但是,由于化粪池污水COD较低,因此无法维持较高的生物量,在后期的稳定运行过程中MLSS始终维持在2 500 mg/L左右.好氧颗粒污泥的同步硝化反硝化作用是其稳定脱氮的保证.     

Ru/γ-Al_2O_3和Ru/AC催化剂的制备及其对氨氧化反应的催化性能

分别以γ-Al_2O_3和活性炭(AC)为载体,采用浸渍法制备了Ru质量分数均为2.0%的Ru/γ-Al_2O_3和Ru/AC催化剂,并用X射线衍射仪和透射电子显微镜等方法对催化剂结构进行了表征.实验结果表明:Ru/AC中Ru沉积在AC表面,分散度较低;而Ru/γ-Al_2O_3中Ru进入到γ-Al_2O_3内部,形成了一种高度分散体系.Ru/γ-Al_2O_3对氨的催化活性高于Ru/AC,氨在Ru/γ-Al_2O_3和Ru/AC上的起活温度分别为200 ℃和266 ℃,T_(90)(氨去除率达90%时的反应温度)分别为267℃和320 ℃.随混合气体空速增大,Ru/γ-Al_2O_3催化剂的T_(90)逐渐升高,气体空速分别为3 600,4 800,5 400 h~(-1)时,T_(90)分别为235,266,303 ℃.随反应前混合气体中氨质量分数增加,氨的去除率降低.     

Effect of ferrate on green algae removal

Green algae Cladophora aegagropila, present in cooling water of thermal power plants, causes many problems and complications, especially during summer. However, algae and its metabolites are rarely eliminated by common removal methods. In this work, the elimination efficiency of electrochemically prepared potassium ferrate(VI) on algae from cooling water was investigated. The influence of experimental parameters, such as Fe(VI) dosage, application time, pH of the system, temperature and hydrodynamics of the solution on removal efficiency, was optimized. This study demonstrates that algae C. aegagropila can be effectively removed from cooling water by ferrate. Application of ferrate(VI) at the optimized dosage and under the suitable conditions (temperature, pH) leads to 100% removal of green algae Cladophora from the system. Environmentally friendly reduction products (Fe(III)) and coagulation properties favour the application of ferrate for the treatment of water contaminated with studied microorganisms compared to other methods such as chlorination and use of permanganate, where harmful products are produced.

     

Toxicity of metalaxyl, azoxystrobin, dimethomorph, cymoxanil, zoxamide and mancozeb to Phytophthora infestans isolates from Serbia

A study of the in vitro sensitivity of 12 isolates of Phytophthora infestans to metalaxyl, azoxystrobin, dimethomorph, cymoxanil, zoxamide and mancozeb, was conducted. The isolates derived from infected potato leaves collected at eight different localities in Serbia during 2005-2007. The widest range of EC(50) values for mycelial growth of the isolates was recorded for metalaxyl. They varied from 0.3 to 3.9 μg mL(-1) and were higher than those expected in a susceptible population of P. infestans. The EC(50) values of the isolates were 0.16-0.30 μg mL(-1) for dimethomorph, 0.27-0.57 μg mL(-1) for cymoxanil, 0.0026-0.0049 μg mL(-1) for zoxamide and 2.9-5.0 μg mL(-1) for mancozeb. The results indicated that according to effective concentration (EC(50)) the 12 isolates of P. infestans were sensitive to azoxystrobin (0.019-0.074 μg mL(-1)), and intermediate resistant to metalaxyl, dimethomorph and cymoxanil. According to resistance factor, all P. infestans isolates were sensitive to dimethomorph, cymoxanil, mancozeb and zoxamide, 58.3% of isolates were sensitive to azoxystrobin and 50% to metalaxyl. Gout's scale indicated that 41.7% isolates were moderately sensitive to azoxystrobin and 50% to metalaxyl.     

基于排队论的城市垃圾箱最佳间距研究

针对城市垃圾箱最佳间距的研究不够精细的现状,本文通过建立排队论模型得到了可供不同城市参考的城市垃圾箱最佳间距参数表。通过对部分城市街道的垃圾箱摆放间距情况进行实地调查,运用层次分析法将影响垃圾箱间距分布的多重因素转化为单因素;建立了基于指数分布的数学模型,利用排队论分析单因素状态下的垃圾箱间距分布,得到了求解城市垃圾箱最佳间距的一般方法。     

Seagrass resource assessment using remote sensing methods in St. Joseph Sound and Clearwater Harbor,Florida, USA

In the event of a natural or anthropogenic disturbance, environmental resource managers require a reliable tool to quickly assess the spatial extent of potential damage to the seagrass resource. The temporal availability of the Landsat 5 Thematic Mapper (TM) imagery provided a suitable option to detect and assess damage of the submerged aquatic vegetation (SAV). This study examined Landsat TM imagery classification techniques to create two-class (SAV presence/absence) and three-class (SAV estimated coverage) SAV maps of the seagrass resource. The Mahalanobis Distance method achieved the highest overall accuracy (86%) and validation accuracy (68%) for delineating the seagrass resource (two-class SAV map). The Maximum Likelihood method achieved the highest overall accuracy (74%) and validation accuracy (70%) for delineating the seagrass resource three-class SAV map. The Landsat 5 TM imagery classification provided a seagrass resource map product with similar accuracy to the aerial photointerpretation maps (validation accuracy 71%). The results support the application of remote sensing methods to analyze the spatial extent of the seagrass resource.     

Socio-economic features of commercial fishery in the bordering upper Danube River area of Serbia

The multidisciplinary socio-economic study of fisheries in the bordering part of the Danube River between Serbia and Croatia (at the following sites: Apatin, Ba?ka Palanka, Ba?ko Novo Selo, Bezdan, and Sombor) that was performed in order to investigate various aspects of fish resource utilization (management, policy of protection and exploitation of freshwater fishery resources, present fisheries legislation, catch statistics), was realized during 2004 and 2005. Data were collected via survey with a structured interview. Socio-economic circumstances, together with ecological factors, have had an influence on the fish stock and number of commercial fishermen. Awareness of the occurring problems, both economic and ecological ones, is apparent, regardless of whether it is assessed in the field of commercial or recreational fishing. Fishery sector in Serbia is in a prolonged process of transition, with the enforcement of fishing regulations, but also the lack of control that leaves space for illegal commercial fishing. The statements, consciousness, experience and behavior of commercial fishermen represent a good basis for planning the sustainable development of fishing in this section of the Danube River.     

Forest biomonitoring of the largest Slovene thermal power plant with respect to reduction of air pollution

The condition of the forest ecosystem in the vicinity of the largest Slovene power plant [the ?o?tanj Thermal Power Plant (?TPP)] was monitored during the period 1991–2008 by determining the total concentration of sulphur, ascorbic acid and chlorophyll in Norway spruce needles. After 1995, the introduction of cleaning devices at the ?TPP dramatically reduced the former extremely high SO₂ and dust emissions. The most significant findings of this comprehensive, long-duration survey are as follows: (1) the chosen parameters are suitable bioindicators of stress caused by air pollution in Norway spruce needles; they reflect both spatial and temporal variations in air pollution as well as the degree of efficiency of the cleaning devices; (2) observations show that the physiological condition of Norway spruce in northern Slovenia has significantly improved since 1995, when the first desulphurization device at ?TPP was built, together with a reduction in the area influenced by pollution from ?TPP; (3) metabolic processes in spruce needles react to air pollution according to the severity of the pollution and the length of exposure; exposure to high SO₂ ambient levels and/or spread over a long duration can damage the antioxidant defence mechanisms of spruce trees as well as diminishing the concentration of ascorbic acid; (4) a reduction in the exposure to air pollution improves the vitality of the trees (e.g. higher concentrations of total (a?+?b) chlorophyll), as well as restoring their defence capabilities as shown by higher concentrations of ascorbic acid; and (5) forest monitoring should be continued and focused on integrating the effects of multiple stressors, which can additionally affect a forest ecosystem.