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521.
污染场地不同深度土壤有机-矿质复合体中有机氯农药的分布 总被引:2,自引:0,他引:2
采用物理方法将某农药厂土壤分成4种粒径的有机-矿质复合体组分,粘粒、粉粒、细砂和粗砂,研究有机氯农药在土壤不同有机-矿质复合体组分中的分布特征及有机质含量对污染物质赋存分布的影响。结果表明,粉粒组分中污染物质六六六含量较高,粘粒组分中滴滴涕含量较高。粘粒和粉粒组分中污染物质的含量与相应的有机质含量间呈现显著相关关系,而在细砂和粗砂中这种相关性不显著。lgKoc值与污染物质含量的相关性分析结果与有机质的相关性分析结果相似。有机质可能是影响场地土壤有机氯农药分布的重要因素之一。本研究的结果可为污染场地的风险控制和环境修复提供基础依据。 相似文献
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524.
由于土地与其他自然资源的限制,经济增长速度相比没有限制情况下降低的现象,即为资源对经济增长的阻尼效应。本文将土地资源与生态环境影响因素合并,利用生态足迹模型解释资源环境复合要素,对传统的阻尼模型进行修正,定量测算资源环境对南京市经济发展的增长阻尼。结果表明,南京市经济发展迅速,土地资源和生态环境对经济发展产生了较为明显的制约作用,其对经济发展的增长阻尼为0.03611。充分发挥资本对资源环境的替代作用,合理利用土地资源,优化产业结构,降低人口的增长率是实现南京市经济可持续发展的基本途径。 相似文献
525.
A pilot biotrickling filter (BTF) packed with ZX02 fibrous balls as packing material was tested for the treatment of ammonia (NH3) released from a composting plant of dairy manure. In order to investigate the effects of three compost aeration modes (mode Co-I, Co-II and In-II) on the NH3 removal efficiency, a field experiment was continuously carried out for more than eight months. The results demonstrated that under the intermittent aeration mode (In-II), the NH3 removal efficiency reached 99.2 ± 0.1% when the inlet NH3 concentration was 7.5-32.3 mg m−3 (9.8-42.5 ppmv). The maximum and critical elimination capacity of the biotrickling filter was 22.6 and 4.9 g NH3 m−3 h−1, respectively. The effluent concentration of NH3 was lower than 1.0 mg m−3, which meets the first class discharge standards of GB14554-93. When the concentration of free ammonia in the trickling liquid was varied from 0.1 to 0.4 mg L−1, the nitrification yield was between 47.9% and 103.8%. In addition, the optimum liquid tricking velocity (LTV) of the biotrickling filter was 0.5 m3 m−2 h−1 for low inlet concentrations and 2.2 m3 m−2 h−1 for high inlet concentrations. Therefore, the use of the biotrickling filter for the compost under the third aeration mode (In-II) yielded an effective optimum NH3 removal and reduced the nitrogen loss in the compost. 相似文献
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527.
Bing Xue Yong Geng Wan-xia Ren Zi-long Zhang Wei-wei Zhang Chen-yu Lu Xing-peng Chen 《Journal of Material Cycles and Waste Management》2011,13(4):283-292
Rapid industrialization and urbanization in developing countries have created serious problems in municipal solid waste (MSW)
management. New case studies can shed light on these problems and point the way to potential solutions for improving the overall
eco-efficiency of MSW management. This paper employs a case study approach, analyzing MSW management in Inner Mongolia. This
study encompasses all aspects of MSW management, including collection, separation, recycling, and disposal. Problems and challenges
are identified through our analysis, and recommendations are raised by considering the local realities. Our main findings
are: (1) while large cities have already established a solid foundation for MSW management, small- and medium-sized cities
deserve more attention; (2) MSW in rural areas is even worse than urban areas; (3) enforcement of MSW regulations is ineffective
and needs improvement; (4) lack of funds, R&D efforts and advanced technologies have impeded sustainable MSW management; (5)
lack of coordination and communication among different stakeholders further damages the efforts for improvement of MSW management.
Therefore, integrated efforts that combine the above concerns should be initiated so that the overall effectiveness and efficiency
of MSW management can be improved. 相似文献
528.
Bioaccumulation and physiological effects of tetrabromobisphenol A in coontail Ceratophyllum demersum L 总被引:2,自引:0,他引:2
Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants. In the present study, the accumulation of TBBPA and its consequent biological responses were examined in coontail (Ceratophyllum demersum L.) over 14 days' exposure. Most of the TBBPA was accumulated after 4d exposure and TBBPA concentration in plant increased with increasing TBBPA concentration in growth solution (R(2)=0.99). By using electron paramagnetic resonance (EPR), we found that the TBBPA exposure significantly increased total free radicals generation in the plants. A good positive relationship (R(2)=0.99) was found between the free radicals formation and accumulation level of TBBPA in plant. Lipid peroxidation was enhanced and chlorophyll content showed declined after TBBPA exposure. The activities of superoxide dismutase (SOD), peroxidase (POD), and the contents of glutathione were also detected. The results suggest that TBBPA accumulation in C. demersum induces oxidative stress and the level of tolerance depends on the antioxidative capacity of the plants. 相似文献
529.
In this work, the formation of the inclusion complex of bisphenol Z (1,1-bis(4-hydroxyphenyl)cyclohexane, abbreviated as BPCH) with beta-cyclodextrin (beta-CD) has been studied, 1:1 inclusion complex can be obtained, the formation constant of the beta-CD/BPCH complex is 5.94x10(3)M(-1). The photodegradation behavior of BPCH was investigated under monochromatic UV irradiation (lambda=254 nm). The photodegradation rate constant of BPCH in aqueous solutions with beta-CD showed a 9.0-fold increase, and simultaneously the mineralization of BPCH can be enhanced by beta-CD. The influence factors on photodegradation of BPCH were also studied and described in details, such as concentration of beta-CD, initial concentration of BPCH, organic solvent and pH. The photodegradation of BPCH in the presence of beta-CD includes the direct photolysis and the photooxidation of BPCH during the photochemical process. Some predominant photodegradation products are 4-(2,4,5-trihydroxy-phenyl)-4-(4-hydroxyphenyl) butanoic acid, 5,5-bis(4-hydroxyphenyl)pentanoic acid, meta-hydroxylated BPCH, ortho-hydroxylated BPCH and 4-(1-(4-hydroxyphenyl)pentyl)phenol respectively. The enhancement of photodegradation of BPCH mainly results from moderate inclusion depth of BPCH molecule in the beta-CD cavity. This kind of inclusion structure allows BPCH molecule sufficient proximity to secondary hydroxyl groups of the beta-CD cavity, and these hydroxyl groups could be activated and converted to hydroxyl radicals under UV irradiation, which can enhance the photooxidation of BPCH. 相似文献
530.
通过农产品质量认证的合作社影响农业化肥用量的理论机制与实证分析 总被引:1,自引:0,他引:1
化肥减量施用是实现中国农产品质量安全与农业绿色高质量发展的重要举措之一,而小规模分散化的经营格局不利于化肥减量技术的推广使用。农民合作社是弥补小规模经营不足与实施农产品质量认证的重要制度安排,其能否以及如何促进农业化肥减量是当前亟待回答的重大现实问题。本文阐明了通过农产品质量认证的合作社对农业化肥用量的影响及作用机制,并基于2007—2018年中国30个省级(市、自治区)面板数据展开实证分析。研究结果表明:通过农产品质量认证的合作社存在显著的化肥减施效应,其主要通过质量溢价、组织规范、组织支持传导路径实现农业化肥减量。从区域差异看,在化肥用量处于高分位点的省份,通过农产品质量认证的合作社表现出更为显著的化肥减施效应;从农作物差异看,通过农产品质量认证的合作社对农业化肥减量施用的贡献主要来自水稻、小麦、玉米三大粮食作物,以及棉花、甘蔗、苹果、柑子四类经济作物的化肥减施效应。 相似文献