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981.
分析了2006-2009年北京环境信访数据,结果显示:北京的环境信访主要集中在大气污染和噪声问题方面,两者分别占信访总量的60%和34%。大气污染包括工业废气、机动车尾气、锅炉烟尘、餐饮油烟、扬尘以及异味等。噪声问题主要是社会生活噪声、工业噪声、施工噪声以及交通噪声等。环境信访量的区域分布与污染源的数量以及人口密度相关。北京城市功能拓展区占全市环境信访的一半以上,发展新区和城市核心区比例分别为26%和13%,生态涵养区仅占4%。从区县分布来看,朝阳区和丰台区比例最高,分别占全市的20%和17%;远郊区县比例相对较低,延庆县不足1%。不同季节污染源排放强度及居民生活规律的差异造成北京环境信访量夏季高、冬季低,8月份信访量是2月份的5倍。奥运前,北京环境信访量不断攀升,其后有所回落,但近几年集中信访突出. 相似文献
982.
近年来,海洋微塑料污染已成为全球关注的重要环境问题。海洋中广泛存在的微塑料可被藻类吸附、微生物定植,亦可被海洋动物摄食并蓄积。生物与微塑料之间的相互作用必然会改变微塑料的物理、化学性质,及其在海洋中的迁移转化。因此,本文系统地阐述了海洋生物对微塑料的吸附、摄入、蓄积与排泄等关键过程;重点总结了微塑料在海洋生物过程(如排泄、与海洋雪团聚、形成生物膜以及生物扰动)影响下的沉降-埋藏等迁移过程;深入讨论了海洋动物对微塑料的摄食、消化过程以及微生物的分解作用导致的微塑料破碎、降解以及塑料添加剂和吸附污染物的释放过程及其机理。本文阐明了海洋生物对微塑料迁移转化的调控作用,为理解海洋微塑料的环境归趋提供理论依据。 相似文献
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Characterization of biological responses under different environmental conditions: A hierarchical modeling approach 总被引:1,自引:0,他引:1
A natural river system is organized as a nested hierarchy of interconnected habitats with specific environmental conditions to which the biological community has adapted. Due to this hierarchical structure, identifying the role of different stressors on the biological community is a formidable task. Efforts trying to link stressors to biological integrity have always been bound to the geographic scale of the selected study area, leading to scale-specific results. In this research, an attempt is made to lift this limitation and develop a hierarchical, scale-sensitive methodology that can identify the significant environmental stressors to the biological community at different scales. Sites with similar background environmental conditions are clustered using self-organizing maps (SOM). This is used to identify stressors which affect the biological community throughout the area of study - called environmental gradients or large-scale stressors. Subsequently, these clusters of similar observations (sampling sites) are progressively sub-divided using environmental variables with a significant but localized effect on the biological community - called small-scale stressors. A parent group of sites is split only when the resulting sub-groups have significantly different biological responses. At the end of this recursive sites decomposition procedure, the original set of observations is organized as a tree of environmentally homogeneous groups of observations characterized by unique biological responses to multiple stressors with different geographic extents. The developed hierarchical analysis methodology has been validated using a large-size dataset of environmental observations from the State of Ohio. Our results show that habitat degradation and increased nutrient loading are the large-scale stressors with a widespread impact in Ohio. Other stressors, such as heavy metals, pH or nitrate concentrations have significant albeit localized effects on biological integrity. 相似文献
984.
Sajjad Haider Rab Nawaz Muzammil Anjum Tahir Haneef Vipin Kumar Oad Salah Uddinkhan Rawaiz Khan Muhammad Aqif 《Frontiers of Environmental Science & Engineering》2023,17(9):111
985.
Catalytic water phase processes as an environmental application is a relatively novel subject with tremendous potential in the near future. This review of 120 references presents the wide scale of heterogeneous water phase applications studied mainly within past five years. Both oxidation and hydrogenation processes are included as well as TiO2 assisted photocatalysis. According to the references, heterogeneous catalysis is developing rapidly. New bimetallic catalysts and supports with higher surface area have improved catalytic efficiency in both oxidation and hydrogenation processes. It also seems that study on use of some waste materials such as red mud as catalyst is a very progressive field. On the whole, the chemical aspects are pretty well known, but the catalyst durability, and in many cases activity as well, has to be improved. 相似文献
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Metals from automotive brake pads pollute water, soils and the ambient air. The environmental effect on water of antimony (Sb) contained in brake pads has been largely untested. The content of Sb in one abandoned brake pad reached up to 1.62 × 104 mg/kg. Effects of initial pH, temperature and four organic acids (acetic acid, oxalic acid, citric acid and humic acid) on Sb release from brake pads were studied using batch reactors. Approximately 30% (97 mg/L) of the total Sb contained in the brake pads was released in alkaline aqueous solution and at higher temperature after 30 days of leaching. The organic acids tested restrained Sb release, especially acetic acid and oxalic acid. The pH-dependent concentration change of Sb in aqueous solution was best fitted by a logarithmic function. In addition, Sb contained in topsoil from land where brake pads were discarded (average 9 × 103 mg/kg) was 3000 times that in uncontaminated soils (2.7 ± 1 mg/kg) in the same areas. Because potentially high amounts of Sb may be released from brake pads, it is important that producers and environmental authorities take precautions. 相似文献
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