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排序方式: 共有432条查询结果,搜索用时 171 毫秒
1.
《山东国土资源》2005,21(4):47-47
1970年4月22日,美国的丹尼斯·海斯在校园发起和组织了群众性的环境保护运动。在这一天,全美国约有 2000 多万人走上街头,举行游行、集会和演讲,呼吁政府采取措施保护环境。这次规模盛大的活动震撼朝野,促使美国政府于 70 年代初通过了水污染控制法和清洁大气法的修正案,并成立了美国环保局。从此,美国民间组织提议把 4 月 22 日定为“地球日”,它的影响随着环境保护的发展而日趋扩大并超过了美国国界,得到了世界许多国家的积极响应。1972 年联合国人类环境会议在斯德哥尔摩召开,1973 年联合国环境规划署成立。到1990年4月22 日,我国原国务… 相似文献
2.
Photoinduced toxicity single and binary mixtures of four polycyclic aromatic hydrocarbons to the marine diatom Skeletonema costatum 总被引:1,自引:0,他引:1
Diatom Skeletonema costatum Cleve is one of the main predominant phytoplankton species in the Changjiang Estuary in China. In order to provide some basic information for future assessment of the potential risk on phytoplankton communities in this estuary caused by polycyclic aromatic hydrocarbons(PAHs), this alga was selected as a representative to investigate the photoinduced toxicity of PAHs, in single and mixture. Four PAHs including three-ring phenanthrene and anthracene, four-ring fluoranthene and pyrene were tested in the laboratory. The single toxicity of each PAH on this microalga was compared with and without the simulated solar UV radiation. The results showed that this microalga was sensitive to PAH's photoinduced toxicity. Ratios of the 72 h median effect concentration obtained for fluorescent and UV light tests were about 8.4 for phenanthrene, 13.0 for anthracene, 6.5 for fluoranthene, and 5.7 for pyrene, indicating that UV light enhanced the PAH toxicity to this alga significantly. Under the fluorescent radiation (lacking UV), the dose-response curves based on chemical concentrations revealed that the order of toxic strength was fluoranthene greater than pyrene greater than anthracene greater than phenanthrene; while under the UV radiation (476 μW/cm2 for UVA, 6.5 μW/cm2 for UVB) it became fluoranthene approximately equaling anthracene greater than pyrene greater than phenanthrene, indicating that the UV light also changed its relative toxicity to this alga. The photoinduced toxicity of PAHs to the marine diatom S. costatum might be a synergistic effect of photosensitization reactions (e.g., generation of single-state oxygen) and photomodification (photooxidation and/or photolysis).The combined effects of six binary mixtures on the marine diatom S. costatum were investigated using the additive-index method. Four binary-mixtures (phenanthrene plus anthracene; phenanthrene plus pyrene; anthracene plus fluoranthene; anthracene plus pyrene) were found to be synergistic joint action mode, while two binary-mixtures (phenanthrene plus fluoranthene; fluoranthene plus pyrene) displayed antagonist, revealing a complex pattern of possible interactions. The combined action mode of PAHs might be related to various factors such as the mixture compounds, mixture ratios and test conditions, etc. 相似文献
3.
Nowadays there are some chronic serious environmental problems, such as eutrophication, blue tide and so on, in a complicated coastal zone or a semi-enclosed bay, because the water exchanges between an inner bay and an outer sea is weak compared with the supply of contaminant. Under this situation, a method to improve the water quality by 3-dimensional small unsymmetrical structures has been proposed by Komatsu et al. In this paper, several numerical simulations of the tidal current and concentration for various arrangements of bottom roughness in a semi-enclosed model bay are carfled out with a depth-averaged 2-D numerical model. The model is solved by the hybrid finite analytic method with nonstaggered grid. And the SIMPLES algorithm with Rhie and Chow' s momentum interpolation technique is used for the simulation. The effect of Komatsu' s method for water purification is examined by numerical simulation. The result of numerical experiment indicates that it is possible to generate a new tidal residual current and to activate a tidal exchange by bottom roughness arrangement only. 相似文献
4.
网箱养殖水污染及其治理对策 总被引:17,自引:1,他引:17
上世纪90年代中期以来 ,各地对渔业捕养关系加大了调整力度 ,网箱养殖业发展迅猛。但随之而来的是网箱养殖水域的水污染问题日益突出 ,制约了网箱养殖业的健康发展。以宁波市辖区内的象山港水域为例 ,近年来 ,投饵网箱养鱼遍及全港 ,网箱数量已超过50000余只。而这些网箱投喂的过剩饵料和鱼类排出的粪便正以每年几十厘米的厚度沉积水底 ,日积月累已达1m多厚。除了靠风浪冲刷等自然作用外 ,没有办法将其清除 ,致使水质严重恶化 ,鱼病蔓延。同时由于水质的“富营养化” ,促使藻类繁衍 ,赤潮时有发生。因此 ,有专家断言 ,网箱养殖的“… 相似文献
5.
基于二次散射的水污染遥感模型及其在珠江口水域的应用 总被引:10,自引:1,他引:10
根据水中悬浮物、污染物和水分子等的散射和吸收物理机制建模是实现水污染定量遥感的有效途径.基于一次散射的水污染遥感模型简单易行,但在浑浊度较大时其精度不高.在基于一次散射模型的基础上分析了多次散射的能量组成特点,提出再考虑二次散射可使模型的精度显著提高且不至于使模型过于复杂;导出了二次散射的补偿因子,同时给出了考虑二次散射因子的简单计算方法.将该模型应用于珠江口水域的水污染遥感的结果表明,较之基于一次散射的模型,考虑二次散射的水污染遥感模型在精度上有明显改进.遥感提取结果显示,珠江口水域重污染区主要分布在伶仃洋东北部,香港维多利亚港和深圳湾. 相似文献
6.
陈登勤 《山东海洋学院学报》1982,12(2):55-56
紫露草(Trddescantia)微核技术用于监测环境污染的研究,国外已有五年多的历史(1-3)。1980年,此种技术的创始者,美国西伊里诺大学马德修教授来我院合作,在我国也开始了这方面的研究工作。在监测空气、工业废水及农药等的污染方面,取得了一定成果(4,5)。 相似文献
7.
8.
Savitri Tripathi Vandana Parth Phani Homeshwari M. Vittal Babu N. Murthy N.N. Sorlie J.E. Govil P.K. 《中国地球化学学报》2006,25(B08):117-118
Permeable Reactive Barrier (PRB) is an emplacement of inert material (s) in the subsurface, designed to intercept a contaminated plume, provides a preferential flow path through the reactive media, and transforms the contaminant into environmentally acceptable forms to attain concentration remediation goals at the discharge of the barrier. The phenomena, which help in remediation within PRB, are adsorption/sorption, precipitation, oxidation/reduction and biodegradation. Various materials like zero-valent iron, zero-valent bi-metals, natural zeolites, organic carbon, fly ash, zeolites, limestone, activated alumina, apatites, etc. have been tried by many researchers to remove organic and inorganic contaminants. In USA, Canada, and many European countries commercial full-scale and pilot scale PRBs are successfully working. The design and installation of full scale PRBs needs laboratory treatability and dynamic flow column experiments? The concept of PRB is being applied to treat contaminated surface water in the Katedan industrial area, Hyderabad, India. National Geophysical Research Institute (NGRI), Hyderabad, India, conducted systematic studies in collaboration with Norwegian Geotechnical Institute (NGI), Norway, to develop PRB technique to decontaminate the surface water pollution due to industrial effluent. A site assessment study in the Katedan Industrial Area, were carried out and water, soil and sediment from the lakes of the area were found to be polluted with high concentrations of heavy metals like As, Pb, Cr, Cd, Ni, etc. Adsorption studies at NGRI with synthetic samples and in-situ industrial effluent using different reactive media for removing contaminants like arsenic, chromium, cadmium, copper, nickel, lead and zinc have been carried out and yielded satisfactory results. The performance of zero-valent iron and limestone is encouraging in removing As, 相似文献
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