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961.
国内甲醇废水处理技术应用现状 总被引:12,自引:2,他引:10
介绍了汽化法、厌氧生物处理法和好氧化生物处理法在国内甲醇废水处理中的应用情况,存在的问题,并提出了一些改进建议。 相似文献
962.
本文调查研究了日本弓背蚁的群体结构和生物学特性,并初步探讨了日本弓背蚁的营养价值及其开发利用对策. 相似文献
963.
D. S. Olsen A. C. Whitaker D. F. Potts 《Journal of the American Water Resources Association》1997,33(6):1197-1207
ABSTRACT: Stream channel stability is affected by peak flows rather than average annual water yield. Timber harvesting and other land management activities that contribute to soil compaction, vegetation removal, or increased drainage density can increase peak discharges and decrease the recurrence interval of bankfull discharges. Increased peak discharges can cause more frequent movement of large streambed materials, leading to more rapid stream channel change or instability. This study proposes a relationship between increased discharge and channel stability, and presents a methodology that can be used to evaluate stream channel stability thresholds on a stream reach basis. Detailed surveys of the channel cross section, water surface slope, streambed particle size distribution, and field identification of bankfull stage are used to estimate existing bankfull flow conditions. These site specific stream channel characteristics are used in bed load movement formulae to predict critical flow conditions for entrainment of coarse bed material (D84 size fraction). The “relative bed stability” index, defined as the ratio of critical flow condition to the existing condition at bankfull discharge, can predict whether increased peak discharges will exceed stream channel thresholds. 相似文献
964.
965.
胜利油田位于我国黄河三角洲地区,潜水位高,水的矿化度大。生态环境恶劣,对植物尤其对木本植物的生长不利,整个地区生长的多是抗盐碱能力强的草本植物。针对油田的特殊环境条件,综合有关资料,介绍了以沙枣为代表的植物特性,特别强调了其抗盐碱、降低土壤矿化度和潜水位、增加土壤有机质和引起植被变化的特性。指出黄河三角洲也有些土质较好的、适于作物和木本植物生长的地区,改良盐碱地可以以这些地区为基点,放射性地向外逐步试验沙枣的种植,以探索改善生态环境的途径。努力做到边发展经济,边改善环境,达到经济效益、社会效益和环境效益三统一。 相似文献
966.
文中介绍了国外用土壤空气抽取法和堆肥法清除土壤中有机溶剂、芳香烃类和石油污染物的技术及其应用。这两种方法单独使用均可成功地治理有害废弃物。实践证明,将这两种技术串联使用可更有效地处理土壤中污染物及加速生物降解过程。根据现场特点,利用多种治理技术综合治理土壤污染物是治理污染物的发展方向。 相似文献
967.
Methods development and use of macroinvertebrates as indicators of ecological conditions for streams in the Mid-Atlantic Highlands Region 总被引:2,自引:0,他引:2
Klemm DJ Blocksom KA Thoeny WT Fulk FA Herlihy AT Kaufmann PR Cormier SM 《Environmental monitoring and assessment》2002,78(2):169-212
The Mid-Atlantic Highlands Assessment (MAHA) included the sampling of macroinvertebrates from 424 wadeable stream sites to determine status and trends, biological conditions, and water quality in first through third order streams in the Mid-Atlantic Highlands Region (MAHR) of the United States in 1993–1995. We identified reference and impaired sites using water chemistry and habitat criteria and evaluated a set of candidate macroinvertebrate metrics using a stepwise process. This process examined several metric characteristics, including ability of metrics to discriminate reference and impaired sites, relative scope of impairment, correlations with chemical and habitat indicators of stream disturbance, redundancy with other metrics, and within-year variability. Metrics that performed well were compared with metrics currently being used by three states in the region: Pennsylvania, Virginia, and West Virginia. Some of the metrics used by these states did not perform well when evaluated using regional data, while other metrics used by all three states in some form, specifically number of taxa, number of EPT taxa, and Hilsenhoff Biotic Index, performed well overall. Reasons for discrepancies between state and regional evaluations of metrics are explored. We also provide a set of metrics that, when used in combination, may provide a useful assessment of stream conditions in the MAHR. 相似文献
968.
Effects of Regional Reductions in Sulphur Deposition on the Chemical and Biological Recovery of Lakes within Killarney Park, Ontario, Canada 总被引:3,自引:0,他引:3
Snucins E Gunn J Keller B Dixit S Hindar A Henriksen A 《Environmental monitoring and assessment》2001,67(1-2):179-194
The lakes in KillarneyProvincial Park, located 40–60 km southwest ofSudbury, Ontario, were some of the first lakesin North America to be acidified by atmosphericpollutants. Acidification affected thousandsof fish and invertebrate populations in dozensof lakes. Since the 1970's, water quality hasimproved in response to atmospheric pollutionreductions and some lakes have alreadyrecovered to approximately their pre-industrialpH levels, as inferred from diatom microfossilsin lake sediments. Since the 1970's, fishspecies richness has not changed substantially,but zooplankton species richness has increasedin acidified lakes. The critical sulphur load,the amount of SO2-derived acid depositionthat can occur while still maintaining suitable water quality, was estimated to beexceeded in 38% of the park area in 1997. Depending on which of four possible NorthAmerican emission control scenarios (CLR =currently legislated reduction; CLR + 25%; CLR+ 50%; CLR + 75%) is achieved by 2010, theprojected critical loads will be exceeded inabout 0-30% of the park area in the future. There are many factors that can affectbiological recovery rates of damaged lakes, butit is expected that biological recovery willlag considerably behind observed chemicalrecovery rates. 相似文献
969.
On Developing Bioindicators for Human and Ecological Health 总被引:5,自引:0,他引:5
Risk assessors and risk managersgenerally either examine ecological health (usingbioindicators) or human health (using biomarkers ofexposure or effect). In this paper we suggest thatit is possible and advantageous to developbioindicators that can be used to assess exposureand effect for both human and non-human receptors. We describe the characteristics of suitablebioindicators for both human and ecological health,using mourning doves (Zenaida macroura),raccoons (Procyon lotor), and bluefish (Pomatomus saltatrix) as examples, and list thegeneral characteristics of other species that wouldmake them useful indicators for assessing both humanand ecological health. Bioindicators can beused cross-sectionally to assess the status ofecosystems and risk as well as longitudinally formonitoring changes or evaluating remediation. Forboth human and ecological risk assessment, there arethree sets of characteristics to consider whenselecting bioindicators: biological relevance,methodological relevance, and societal relevance. An indicator which fails to fulfill these is notlikely to be considered cost-effective and is likelyto be abandoned. The indicator should be readilymeasured and must measure an important range ofimpacts. For long-term support of a bioindicator,the indicator should be easily understood, and becost effective. We suggest that bioindicators thatcan also be used for both ecological and humanhealth risk assessment are optimal. 相似文献
970.