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81.
综述了水生植物对氮、磷、重金属及有毒有机物等各类污染物的清除作用及其在污染治理中的应用实践,同时对水生植物在废水处理和湖泊治理方面的应用提出了相应的建议。  相似文献   
82.
The purpose of the present research is to collect information about accidents and incidents that have occurred at fuel ethanol facilities from 1998 to October 2014, and to keep complete unified records of them in a database. The developed database contains general information about the accident or incident, its sequence, mitigation measures, its causes and consequences for humans, environment and for the plant. Until now, this information is not available. The work consisted in gathering information from different documental sources and subsequent organization in a database. It complements the previous work made for biodiesel industry and fills the existing gap in the field of ethanol. Knowledge about this information enables us to manage plant risks, since the accidents that are more likely to occur and the main sources of risk can be easily identified. Also, it makes it possible to exchange information with interested third parties. Statistical analysis shows that accident frequency has an oscillatory behavior, rising in the last year. Fire is the most common type of accident, while equipment mechanical failure is the main cause of accident. Partial material loss has been identified as the most common consequence. Finally, some conclusions are obtained concerning to the importance of having an updated and complete accident and incident database.  相似文献   
83.
提出了一套基于神经网络分类器的城市污水处理厂水力负荷冲击预警系统,以期对进水水量骤增现象进行提前1天的预报,使污水处理厂可根据预报结果提前采取水力冲击防护措施,从而保证各单元的平稳运行.根据进水水量的涨幅将某污水处理厂12年日进水水量监测数据分为"常规"和"冲击"两类,重点对"冲击"数据进行提前1天的预测,并采用冲击漏报率、冲击误报率和报准率对模型的预测精度进行评价;同时,基于同样的建模方法和不同的训练、验证样本建立了N(1)、N(2)和N(3)3个平行模型,以对模型的鲁棒性和建模方法的可重复性进行考察.结果显示,3个模型对2010年、2011年和2012年3年测试样本的预测效果良好,冲击漏报率和报准率两项指标数值均较为稳定,分别在0~0.167和0.981~0.995之间浮动,冲击误报率虽然在数值上的浮动较大,最低为0.143,最高为0.500,平均为0.310,但仍在工程上的可承受范围内.该结果表明,本研究基于神经网络分类器所建立的3个神经网络模型预测精度高、鲁棒性好,显示出良好的性能,有望为污水处理厂水力冲击防护工作提供有力参考.  相似文献   
84.
Piriformospora indica, a root-colonizing endophytic fungus of Sebacinales, promotes plant growth and confers resistance against biotic and abiotic stresses. In order to confirm the influence of P. indica on growth, proline, malondialdehyde (MDA), chlorophyll, and cadmium (Cd) amounts in Nicotiana tabacum under Cd stress, hydroponics, pot and field trials were conducted. The results showed that P. indica can store Cd in plant roots and reduce leaf Cd content, reduce the concentration of MDA, and increase the proline and chlorophyll content and the activities of catalase, peroxidase, and superoxide dismutase under hydroponic Cd stress. RT-PCR analysis showed that the relative expression level of genes Gsh2, TaPCS1, oas1, GPX, and Hsp70 in colonized plants was 4.3, 1.4, 2.9, 1.7, and 6.9 fold higher than in un-colonized plants respectively. Cd exposure significantly reduced un-colonized plants'' agronomic traits compared to P. indica-colonized ones. Our results suggested that P. indica can sequester Cd in roots, so that much less cadmium was transported to leaves, and the increased concentrations of antioxidant enzymes, pigments and proline contents, as well as the higher expression of stress-related phytochelatin biosynthesis genes in P. indica-inoculated plants, may also serve to protect N. tabacum plants against oxidative damage, enhancing Cd tolerance.  相似文献   
85.
Plant invasions are a serious threat to natural and semi-natural ecosystems worldwide. Most management-orientated research on invasions focuses on invaders that are already widespread and often have major impacts. This paper deals with "emerging" invaders-those alien species with the potential to become important problems without timely intervention. A climate matching procedure was developed to define areas of South Africa, Lesotho and Swaziland that could be invaded by 28 plant species that had previously been classified as emerging invaders. Information on the location of populations of these species in the study area was combined with information on their distributions (as native or alien) in parts of Australia and the United States of America. These two countries had the best available distribution data for this study. They also share many invasive alien plant species with South Africa. Climatic data obtained for weather stations near points of known occurrence in these countries were used to define the climatically suitable areas for each species in the study area. Almost 80% of the remaining natural environment in southern Africa was found to be vulnerable to invasion by at least one of these species, 50% by six or more and 24% by 16 or more species. The most vulnerable areas are the highveld grasslands and the eastern escarpment. The emerging invaders with the greatest potential range included Acacia podalyriifolia and Cortaderia selloana. The globally important invaders Ulex europaeus and Lythrum salicaria had a more limited invasion potential but could still become major invaders. There was no relationship between the extent of the climatically suitable areas for the different species and an expert ranking of their invasion potential, emphasising the uncertainties inherent in making expert assessments based on very little information. The methods used in this analysis establish a protocol for future modelling exercises to assess the invasion potential of other emerging invaders.  相似文献   
86.
天津塘沽作为滨海新区核心区,是目前天津发展最快的地区之一。由于本区盐碱土壤等自然条件,污水中盐分含量较高,制约了废水的回用。本文通过模拟人工湿地实验,比较了芦苇(Phragmites australis)、盐地碱篷(Suaeda salsa)、碱蒿(Artemisia anethifo原lia)、黄花鸢尾(Iris wilsonii)、盐角草(Salicornia europaea)和大米草(Spartina anglica)等耐盐植物对轻污染水体中高浓度氯离子的去除能力,筛选出去除能力较强的植物,并确定植物对盐分去除率达到最大时的生态系统条件。结果表明,适合人工湿地的耐盐碱植物对氯离子的去除效果依次为:芦苇>盐地碱篷>碱蒿>黄花鸢尾>盐角草>大米草,停留时间一般在第4d时可达到平衡。该研究为利用人工湿地处理高盐废水提供了科学依据。  相似文献   
87.
生物质能(Biomass energy)是最为广泛的可再生能源,其中多年生芒属C4植物(Miscanthus)由于具有巨大碳固定能力而成为潜力巨大的生物质能植物。中国是芒属植物芒草起源中心,但相对于欧洲国家应对能源危机和温室效应而采取的芒草研究与应用来说,仍处于起步阶段。我国长期以来传统的草地利用模式,决定了在南方草地的研究显著少于北方,近年来芒草在华南地区的运用研究集中于生态修复,对草本植物群落基于生态系统水平的 CO2气体交换能力的研究仍然相当缺乏,在二氧化碳浓度持续增长及全球变暖背景下,生物质能植物及其碳汇功能的相关研究尤显重要。我国南方近6700万hm2退化丘陵草坡急待恢复或处于恢复中,草坡地芒属植物符合生物质能植物标准,施肥少,害虫少,农药输入少,能够有效地利用光、水等自然资源。考虑到C4植物具有比C3植物更强的光合作用能力,高光能利用率C4芒属植物的碳固定能力及能源潜力值得重视,但缺乏科学的碳动态和碳收支评估。综述了国内外芒草生物量特征与生物质能潜力研究现状,重点论述芒属植物生态系统水平的碳动态和收支能力研究,探讨了系统水平更客观评估芒属碳源汇(Carbon sequestration)功能的方法,基于生物量过程的研究结果及华南地区草坡研究历史和现状,为草坡地生物质能的合理开发利用提出了相关对策,强调在我国南方开发和利用芒属植物资源具有重要能源价值和经济、环境效益。  相似文献   
88.
A total of six nuclear reactors installed in three power plants, two along the northern and one along the southern coasts of Taiwan, started their operations one after another since October 1977. Owing to the large quantities of cooling water intake into and discharge from the plants, some environmental factors such as water temperature, chlorine, environmental radioactivity and nearshore currents may be significantly changed. Variations of these abiotic environmental factors may influence the biological activities in the ecosystem, particularly doing some kinds of damage to marine biological resources. Therefore, the possible environmental impact upon the biological systems including the fishery resources along the northern and southern coasts of Taiwan should be studied before and during the plant operation.

We have started the long-term programmes of biological, chemical and hydro-graphical surveys of the nuclear power plant sites on both northern (since July 1974) and southern (since July 1979) coasts of Taiwan. the survey items include ocean currents, physical and chemical properties of sea water, primary productivity, specific compositions and interspecific relationships among phyto- and zooplankton, algae, invertebrates, corals, and fishes; and radionuclides in water and biological specimens, and fishery statistics. in general, except for a few events, the operations of the six units of nuclear power plants have not produced detectable effects on the marine ecosystem. Radio activity levels and radionuclides in water and the biological specimens remained the same as background levels throughout the survey period. However, the events of coral bleaching and fish body anomalies caused by thermal discharges were observed respectively along the outlets of third and second Nuclear Power Plants. the purposes of this paper are to report and evaluate these two events during the operations of nuclear power plants in Taiwan.  相似文献   
89.
火电行业是我国经济社会发展的重要基础和保障,但也是碳排放的主要源头之一。在“双碳”目标约束下,新能源装机将持续增长,而火电机组则面临降碳和退役的压力。以安徽省为研究区域,考虑“双碳”目标与污染导致的健康损失等因素,对全省现役火电机组的计划退役与有序退役方案进行对比分析,为火电行业实现低碳发展提供路径参考。在有序退役方案下,结合初始投资、使用年限、年度发电收益与污染物排放计算出现役机组每年的净现值,并且根据未来安徽省碳排放削减目标,得到优化后的机组退役时间和顺序。结果表明:与常规的计划退役方案相比,有序退役方案使安徽省火电机组退役时间平均提前约5 a,在2060年碳中和之前可实现现役机组全部退役。2020—2060年,现役机组有序退役可累计减少碳排放量12.76亿t;累计减少SO2、NOx、PM2.5排放量分别为1.44万t、2.13万t、0.17万t,比计划退役方案减少8.66亿元的健康损失。机组的有序退役不仅能带来巨大的环境效益与社会效益,也为“双碳”目标的实现提供了有力保障。  相似文献   
90.
Heavy metal distribution in medicinal plants is gaining importance not only as an alternative medicine, but also for possible concern due to effects of metal toxicity. The present study has been focused on emphasizing the heavy metal status and bioaccumulation factors of V, Mn, Fe, Co, Cu, Zn, Se (essential metals) and Cr, Ni, Cd, As and Pb (potentially toxic metals) in medicinal plants grown under two different environmental conditions e.g., near to Khetri copper mine and those in fertile soils of Haridwar, both in India, using Instrumental Neutron Activation Analysis (relative method) and Atomic Absorption Spectrometry. The copper levels in the medicinal plants from Khetri were found to be 3-4 folds higher (31.6–76.5 mg kg?1) than those from Haridwar samples (7.40–15.3 mg kg?1), which is correlated with very high copper levels (763 mg kg?1) in Khetri soil. Among various heavy metals, Cr (2.60–5.92 mg kg?1), Cd (1.47–2.97 mg kg?1) and Pb (3.97–6.63 mg kg?1) are also higher in concentration in the medicinal plants from Khetri. The essential metals like Mn (36.4–69.3 mg kg?1), Fe (192–601 mg kg?1), Zn (24.9–49.9 mg kg?1) and Se (0.13–0.91 mg kg?1) and potentially toxic metals like Ni (3.09–9.01 mg kg?1) and As (0.41–2.09 mg kg?1) did not show much variations in concentration in the medicinal plants from both Khetri and Haridwar. The medicinal plants from Khetri, e.g., Ocimum sanctum, Cassia fistula, Withania somnifera and Azadirachta Indica were found rich in Ca and Mg contents while Aloe barbadensis showed moderately high Ca and Mg. Higher levels of Ca-Mg were found to correlate with Zn (except Azadirachta Indica). The bioaccumulation factors (BAFS) of the heavy metals were estimated to understand the soil-to-plant transfer pattern of the heavy metals. Significantly lower BAF values of Cu and Cr were found in the medicinal plants from Khetri, indicating majority fraction of these metals are precipitated and were immobilized species unsuitable for plant uptake. Overall, Withania somnifera (Ashwagandha) showed very high metal bioaccumulation.  相似文献   
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