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661.
突发性环境事件时间序列特征可表征环境风险管理成效及存在问题。研究表明2000年以来中国突发环境事件预防、控制与管理取得了显著成效,其中,突发性水污染事件、大气污染事件以及噪声振动危害年发生频次呈大幅度降低趋势,但固废污染事件自2003年以来的年发生频次变化不大,而其它突发性环境事件自2002年以来的年发生频次则呈快速增长态势,说明中国在强调突发性水环境和大气环境事件监管的同时,还需加强固废污染事件及其它类型突发环境事件的监控与管理。 相似文献
662.
Cadmium (Cd) is a highly toxic element in water. Its toxicity has been attributed to oxidative stress mediated by free radicals. Here we investigated the effects of Cd on the histopathology, antioxidant enzymes and lipid peroxidation of crustacean heart. The freshwater crabs Sinopotamon yangtsekiense were exposed to different concentrations of Cd for 1, 3, 5 and 7 d. After exposure, histological abnormalities were discovered, including myocardial edema, vacuolar and vitreous degeneration, and infiltration of inflammatory cells. Additionally, alterations in nuclei, mitochondria, rough endoplasmic reticulum as well as myofibrils were observed. Meanwhile, superoxide dismutase (SOD) activity was significantly increased after Cd exposure. Catalase (CAT) activity was only increased in the group exposed to 14.50 mg L−1 Cd on day 5 and decreased with increasing Cd concentration and exposure time. Glutathione peroxidase (GPx) activity was increased in groups treated with 29.00, 58.00 and 116.00 mg L−1 on days 1 and 3, and decreased thereafter. Besides, malondialdehyde (MDA) levels were significantly increased after 3 d of Cd exposure at all the indicated concentrations. These results showed that acute Cd exposure led to harmful effects on the histology of crab heart, which are most likely linked to Cd-induced oxidative stress. 相似文献
663.
Phosphorus (P) is a key biological element and limiting nutrient in aquatic environments. Phosphate (+5) is traditionally associated with the P nutrient supply. However, phosphite (+3) has recently generated a great deal of interest, because of the possibility that it is a P source based on recognition of its vital role in the original life of the early earth. This study investigated whether phosphite can be an alternative P source for Microcystis aeruginosa PCC 7806, one of the predominant bloom species in freshwater systems. The results indicated that M. aeruginosa could not utilize phosphite as a sole P-nutrient directly for cell growth at any concentration, but that phosphite could boost cell numbers and chlorophyll a (Chl-a) content as long as phosphate was provided simultaneously. Specifically, Chl-a production increased sharply when 5.44 mg P L−1 phosphite was added to 0.54 mg P L−1 phosphate medium. Analysis of the maximum yield of PSII indicated that phosphite may stimulate the photosynthesis process of cells in phosphate-phosphite medium. In addition, phosphite failed to support cell growth, even though it more readily permeated the cells in P-deficient medium than in P-sufficient medium. Alkaline phosphatase activity (APA) analysis indicated that, unlike organic P, phosphite inhibits the response of cells to deficient P status, especially under P-deprived conditions. 相似文献
664.
Naile JE Khim JS Wang T Wan Y Luo W Hu W Jiao W Park J Ryu J Hong S Jones PD Lu Y Giesy JP 《Environmental pollution (Barking, Essex : 1987)》2011,159(4):907-917
Polychlorinated-dibenzo-p-dioxins and -dibenzofurans (PCDD/Fs) were measured in soils and sediments from the Yellow Sea region. Korean soils and sediments mostly contained detectable PCDD/Fs and showed a widespread distribution among locations. Soil and sedimentary PCDD/Fs from China were comparable to or less than those in Korea. The patterns of relative concentrations of individual congeners in soils were different between the two countries, but similar in sediments. Sources of PCDD/Fs in China and Korea were found to be independent of each other and their distributions reflected matrix-dependent accumulation. Spatial distribution indicated some point sources in Korea while Chinese sources were more widespread and diffuse. PCDD/Fs measured in the coastal areas of the Yellow Sea were comparable to or less than those previously reported in for eastern Asia. However, ∑TEQs in soils and sediments were near to or, in some cases exceeded environmental quality guidelines. 相似文献
665.
Distribution, speciation and availability of antimony (Sb) in soils and terrestrial plants from an active Sb mining area 总被引:1,自引:0,他引:1
Gudny Okkenhaug Yong-Guan ZhuLei Luo Ming LeiXi Li Jan Mulder 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2427-2434
Here, we present one of the first studies investigating the mobility, solubility and the speciation-dependent in-situ bioaccumulation of antimony (Sb) in an active Sb mining area (Xikuangshan, China). Total Sb concentrations in soils are high (527-11,798 mg kg−1), and all soils, including those taken from a paddy field and a vegetable garden, show a high bioavailable Sb fraction (6.3-748 mg kg−1), dominated by Sb(V). Elevated concentrations in native plant species (109-4029 mg kg−1) underpin this. Both chemical equilibrium studies and XANES data suggest the presence of Ca[Sb(OH)6]2, controlling Sb solubility. A very close relationship was found between the citric acid extractable Sb in plants and water or sulfate extractable Sb in soil, indicating that citric acid extractable Sb content in plants may be a better predictor for bioavailable Sb in soil than total acid digestible Sb plant content. 相似文献
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With intensified contradiction between the rapid development of modern industry and the carrying capacity of natural environment,coordinating the relationship between economic benefits and ecological benefits is a significant issue to be solved for modern industrial engineering.This paper firstly conducts the comparative analysis between traditional and ecological industry as well as traditional and modern industrial engineering,and indicates that eco-industrial engineering is an inevitable choice for sustainable development of modern industrial engineering;Then,based on industrial ecology,environmental economics and sustainable development theory,the connotation and definition of ecoindustrial engineering are proposed,and the theoretical and practical development of the concepts of eco-industrial engineering are further investigated.Furthermore,the research subject,research content,academic system architecture and evaluation methods of eco-industrial engineering are discussed.Finally,combining the current scientific and technological development,we put forward the important scientific value and practical significance of constructing eco-industrial engineering for the utilization of these concepts. 相似文献