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351.
Greater emphasis is being placed on indicators of agri-environmental efficiency of organic production systems. Linking environmental measures with profitability measures based on net income is the only way to develop such indicators. A stochastic production frontier model that explicitly incorporates farm decisions about acquiring and managing organic soil-improving inputs is used to measure efficiency. The results confirm that on-farm self-sufficiency in soil-improving inputs is positively related to farm-level efficiency. 相似文献
352.
Anthony M. Rizzuti Arthur D. Cohen Patrick G. Hunt Matias B. Vanotti 《Journal of environmental science and health. Part. B》2013,48(4):709-748
Abstract This paper reports on research designed to investigate the capacities of different highly characterized peats to remove odorous compounds from liquid swine manure (LSM). Peat types representing a wide range of properties were tested in order to establish which chemical and physical properties might be most indicative of their capacities to remediate odors produced by LSM. Eight percent slurries (of peat/LSM) were measured for odor changes after 24 hours using odor panel and GC/MS‐Solid‐phase microextraction (GC/MS‐SPME) analysis. The GC/MS‐SPME and odor panel results indicated that, although all peats tested in this study were found to be effective at removing odor‐causing compounds found in LSM, some peats tended to work better than others. Overall, the peats that were the most effective at removing odor‐causing compounds tended to have lower bulk densities, ash contents, fulvic acids contents, and guaiacyl lignins contents,and higher water holding capacities, hydraulic conductivities, “total other lignins”; contents, hydrogen contents, carbon contents, and total cellulose contents. GC/MS‐SPME analysis was found to be a reasonably inexpensive and efficient way of conducting this type of research. It allows one to identify a large number of the odor‐causing compounds found in LSM, and more importantly, to detect with some precision specific differences in the amounts of these compounds between peat types. 相似文献
353.
楼静 《中国环境管理干部学院学报》2004,14(2):42-44
渗透蒸发技术是一种新型膜分离技术,主要用于有机溶剂脱水、水中脱除有机物与有 机物之间的分离。本文主要介绍渗透蒸发技术在脱除水中挥发性有机污染物方面的应用。 相似文献
354.
Louise M. Tritton C. Wayne Martin James W. Hornbeck Robert S. Pierce 《Environmental management》1987,11(5):659-666
The objective of this research was to evaluate the impacts of increasing product removal on biomass and nutrient content of a central hardwood forest ecosystem. Commercial thinning, currently the most common harvesting practice in southern New England, was compared with whole-tree clearcutting or maximum aboveground utilization. Using a paired-watershed approach, we studied three adjacent, first-order streams in Connecticut. During the winter of 1981–82, one was whole-tree clearcut, one was commercially thinned, and one was designated as the untreated reference. Before treatment, living and dead biomass and soil on the whole-tree clearcut site contained 578 Mg ha–1 organic matter, 5 Mg ha–1 nitrogen, 1 Mg ha–1 phosphorus, 5 Mg ha–1 potassium, 4 Mg ha–1 calcium, and 13 Mg ha–1 magnesium. An estimated 158 Mg ha–1 (27% of total organic matter) were removed during the whole-tree harvest. Calcium appeared to be the nutrient most susceptible to depletion with 13% of total site Ca removed in whole-tree clearcut products. In contrast, only 4% (16 Mg ha–1) of the total organic matter and 2% of the total nutrients were removed from the thinned site. Partial cuts appear to be a reliable management option, in general, for minimizing nutrient depletion and maximizing long-term productivity of central hardwood sites. Additional data are needed to evaluate the long-term impacts of more intensive harvests. 相似文献
355.
2004年夏季在广州四个不同区域采集大气颗粒物样品,参照美国环保局(US EPA)标准方法测定其中二噁的含量,采用热分解光学分析法测定元素碳和有机碳的含量。结果表明,花都、荔湾、天河、黄埔大气颗粒物中二噁浓度(毒性当量)平均值分别为3815fg/m3(104.6fg I-TEQ/m3)、12777fg/m3(430.5fg I-TEQ/m3)、6963fg/m3(163.7fg I-TEQ/m3)、10953fg/m3(769.3fg I-TEQ/m3)。简单地分析了广州大气颗粒物中二噁的含量特征,以及与元素碳、有机碳之间的相关性。 相似文献
356.
水体有毒有机污染研究 总被引:3,自引:1,他引:3
对有毒有机污染物的主要种类,实际的检出水平,健康影响评价、污染处理技术进行了简要介绍,在此基础上对管理对策进行了探讨。 相似文献
357.
采用GDX-502大孔树脂和GC-MS等仪器对城市河流,湖库中的痕量有机污染物进行测试分析,共检出58种有机污染物,其中含有多种美国EPA公布的重点污染物。因而为痕量有机污染物的研究建立了灵敏度高,分辨率好的测试方法。 相似文献
358.
359.
论述了含汞等7类实验室常见废弃物的处理方法,介绍了6种有机溶剂的3种贵重金属的回收与提纯,以防止污染事故的发生。 相似文献
360.
光合细菌在污水处理中的应用 总被引:2,自引:0,他引:2
李思明 《辽宁城乡环境科技》2003,23(4):36-37
介绍光合细菌作为一种优势菌种可以在处理高浓度有机废水中发挥的作用,谈及到同时在处理中低浓度废水中与其它优势菌种协同处理时的效果。 相似文献