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51.
Stream fish bioassessment methods assume that fish assemblages observed in sample sites reflect responses to local stressors, but fish assemblages are influenced by local factors as well as regional dispersal to and from connected streams. We hypothesized that fish movement to and from refugia and source populations in connected rivers (i.e., riverine dispersal) would weaken or decouple relations between fish community metrics and local environmental conditions. We compared fish-environment relations between streams that flow into large rivers (mainstem tributaries) and streams that lack riverine confluences (headwater tributaries) at multiple spatial grains using data from the USEPA's Environmental Monitoring and Assessment Program in the mid-Atlantic highlands, USA (n = 157 sites). Headwater and mainstem tributaries were not different in local environmental conditions, but showed important differences in fish metric responses to environmental quality gradients. Stream sites flowing into mainstem channels within 10 fluvial km showed consistently weaker relations to local environmental conditions than stream sites that lacked such mainstem connections. Moreover, these patterns diminished at longer distances from riverine confluences, consistent with the hypothesis of riverine dispersal. Our results suggest that (1) the precision of fish bioassessment metrics may be improved by calibrating scoring criteria based on the spatial position of sites within stream networks and (2) the spatial grain of fish bioassessment studies may be manipulated to suit objectives by including or excluding fishes exhibiting riverine dispersal.  相似文献   
52.
In this paper, we first review the development of China’s Environmental Impact Assessment (EIA) system in the past 30 years. Then we compare the framework and operational procedures of China’s new EIA law with those of the EU EIA Directive. We also compare public participation, as well as sanctions and control in the two EIA systems. In addition, we identify where the processes in both EIA systems are similar or different from one another. By comparison, we noted that there are at least three obvious weaknesses in China’s EIA system: (1) the application of new models for EIA legislation; (2) the improvement of EIA guidance and education; and (3) the enhancement of public participation in EIA process. Our study indicates that these three major shortcomings should be overcome and improved in China’s EIA system, when compared with the EU EIA system.  相似文献   
53.
Intent of this study was to explore the potential application of polymerin, the polymeric, dissolved organic matter fraction from olive oil wastewaters, in technologies aimed at remediating hydrophobic organic compounds (HOCs) point-source pollution. Phenanthrene binding with polymerin was investigated. Moreover, the effect of addition of micro and nanoscale aluminum oxides (Al2O3) was studied, as well as sorption of polymerin on the oxides. Phenanthrene binding capacity by polymerin was notably higher than the sorption capacities for both types of Al2O3 particles. Polymerin sorption on nanoparticles was nearly 100 times higher than microparticles. In a three-phase system, using microparticles, higher phenanthrene sorption was found by adding into water polymerin, oxides and phenanthrene simultaneously. In contrast, using nanoparticles, a considerable enhancement of phenanthrene sorption was shown by adding phenanthrene to a pre-formed and dried polymerin-oxide complex. These findings support the application of polymerin, especially associated with Al2O3 nanoparticles, in remediation of water contaminated with HOCs. This work highlights the significant role of nanoparticles.  相似文献   
54.
PH3液相催化氧化净化研究   总被引:2,自引:0,他引:2  
以Mn2 和Pd2 为催化剂的吸收液对含低浓度PH3的混合气进行了液相催化氧化净化研究.考察了催化剂配比、混合气中O2浓度、PH3初始浓度、反应温度、气体流量和吸收液pH与PH3净化效率的关系.结果表明,催化剂中Pd2 与Mn2 的质量比为1:4时可获得较佳的净化效果;随着混合气中O2浓度的增加,吸收液对PH3的净化效率有所提高;在20~75℃内,低温对PH3净化有利,较适宜的反应温度为20℃;较低的PH3初始浓度和低气体流量均有利于PH3的净化;较高的pH有利于吸收液中催化剂催化效能的发挥.吸收液对PH3的净化效率可达100%,但因吸收液中的金属离子易与催化氧化PH3产生的PO3-4形成沉淀,使金属离子脱离液相催化氧化系统,吸收液失效较快.  相似文献   
55.
Thermophilic anaerobic digestion of swine manure represents a potential waste treatment technology to address environmental concerns, such as odor emissions and removal of pathogenic microorganisms. However, there are concerns relative to the stability of this process when swine manure is the sole substrate. In this study, the potential of biogas production from swine manure as the sole substrate under thermophilic (50 degrees C) conditions was investigated in the laboratory, to determine whether separation of urine and feces as part of the waste collection process would benefit anaerobic digestion. Effluent from a continuously stirred tank reactor was used as the inoculum for batch tests, in which the substrate contained three different concentrations of urine (urine-free, as-excreted urine-to-feces ratio and double the as-excreted urine-to-feces ratio). Inocula were acclimated to these same urine-to-feces ratios to determine methane production. Results show that both urine-free and as-excreted substrates were not inhibitory to anaerobic inocula. Anaerobic microorganisms can be readily acclimated to substrate with double the as-excreted urine concentration, which contained nitrogen concentrations up to 7.20 g/L. Cumulative methane production reached similar levels in the batch tests, regardless of the substrate urine concentration.  相似文献   
56.
通过我国航空发动机海洋环境服役过程中腐蚀情况的调研,结合文献资料,分析腐蚀防护与控制技术的应用现状,提出未来工作建议。目前海洋环境服役航空发动机的腐蚀防护与控制缺少贯穿方案论证、设计研制、使用维修等全寿命周期各阶段的综合考虑,制约解决腐蚀问题的关键技术没有突破,研制生产过程中,存在耐腐蚀性能评估不合理的问题。应开展腐蚀智能监测、识别、模拟仿真等技术的研发与应用,实现海洋环境服役发动机的腐蚀损伤监控与预警,构建发动机腐蚀环境适应性试验评价技术体系,满足新体制下装备试验鉴定工作要求。急需开展长寿命防护涂层技术、维护技术专项研究,以适应严酷海洋大气环境和航空动力装置高可靠性研制要求。  相似文献   
57.
介绍了活性碳纤维(ACF)的孔结构及表面官能团,综述了国内外ACF改性技术的研究现状.ACF的改性主要包括孔结构调控和表面化学改性,表面化学改性包括氧化还原法、表面负载法、浸渍法、热处理法、远程等离子体处理法、微波辐照法等,也可将多种方法结合来对ACF进行改性,以改善和提高ACF的吸附性能.在总结现有研究的基础上,对ACF改性技术发展趋势进行了展望.  相似文献   
58.
UASB反应器处理染料及印染废水的研究进展   总被引:1,自引:1,他引:1  
综述了国内外UASB反应器处理染料及印染废水的研究概况.分析了UASB反应器处理废水存在的问题,并给出了相应的建议.展望了UASB反应器处理染料及印染废水的发展趋势,指出厌氧UASB-好氧法组合工艺是目前处理染料及印染废水的一种经济而有效的方法.  相似文献   
59.
基于RS和GIS的长江安庆段岸线资源评价   总被引:1,自引:0,他引:1  
应用遥感影像结合GIS相关技术对长江安庆段岸线进行解译、分类,查清长江安庆段岸线资源分类长度,并采用岸前水深和岸线稳定性两个评价指标对岸线资源进行分等评价,兼顾岸前航道水域宽度和后方陆域场地条件两个限制性因素,综合确定岸线条件的优劣。评价结果:长江安庆段岸线总长度为249.6km,一级、二级优良岸线62.4km,三级岸线187.2km;开发条件较好的岸线有周家湾一套口、沟口-老湖塔和谭家沟-马船沟三段。最后结合安庆市经济发展背景、区位条件对安庆沿江岸线资源开发分段提出若干建议。  相似文献   
60.
贴不贴泡是大庆某石油化工总厂生产废水排放场地,其作用相当于一个水面较大的氧化塘。本文对大庆市贴不贴泡周边地下水采集样品,以研究其对周边地下水的污染状况。结果显示:纳污泡附近地下水受到不同程度石油类污染,石油类污染物还仅限于湖泡区内,在剖面上的分布基本限于潜水层内,局部达到弱透水层顶部附近。石油类污染物在其中的迁移速度很低,特别是水平迁移速度更小,才使污染近30年的场地地下水受到的石油烃污染不是十分严重。  相似文献   
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