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Measuring Hg levels of water sediments is one of the primary routes to assess the trend of the contamination. Little work
has been carried out in the Yangtze Delta to track the trend of mercury contamination caused by Shanghai, which is one of
the fastest growing economies in the world today. The mercury concentration in the sedimentary cores from Dianshan Lake, Shanghai
is studied here. Results show that mercury transported to Dianshan Lake from emissions of coal combustion and non-coal sources
in the Yangtze Delta was greater after 1979. We found also that before 1979 mercury levels changed less with time than after
1979. Before 1967 Hg levels were more variable than in the 1970s. Moreover, the mercury dissolved in river water and bound
to particles of water that flow past downtown Shanghai is different from that observed in Dianshan Lake, which is located
in upper Shanghai. This indicates that atmospheric Hg deposition is probably the main source of mercury in Dianshan Lake.
These results are important for the establishment of environmental protections and pollution treatment proposals for mercury
in similar areas of the world, as well as in Shanghai. 相似文献
684.
Jie Yin Zhane Yin Haidong Zhong Shiyuan Xu Xiaomeng Hu Jun Wang Jianping Wu 《Environmental monitoring and assessment》2011,177(1-4):609-621
This study explored the spatio-temporal dynamics and evolution of land use/cover changes and urban expansion in Shanghai metropolitan area, China, during the transitional economy period (1979?C2009) using multi-temporal satellite images and geographic information systems (GIS). A maximum likelihood supervised classification algorithm was employed to extract information from four landsat images, with the post-classification change detection technique and GIS-based spatial analysis methods used to detect land-use and land-cover (LULC) changes. The overall Kappa indices of land use/cover change maps ranged from 0.79 to 0.89. Results indicated that urbanization has accelerated at an unprecedented scale and rate during the study period, leading to a considerable reduction in the area of farmland and green land. Findings further revealed that water bodies and bare land increased, obviously due to large-scale coastal development after 2000. The direction of urban expansion was along a north-south axis from 1979 to 2000, but after 2000 this growth changed to spread from both the existing urban area and along transport routes in all directions. Urban expansion and subsequent LULC changes in Shanghai have largely been driven by policy reform, population growth, and economic development. Rapid urban expansion through clearing of vegetation has led to a wide range of eco-environmental degradation. 相似文献
685.
在回顾环境功能材料研究进展的基础上,将材料按功效分为固化/稳定化材料、氧化还原剂类材料以及催化剂类材料,重点对固化/稳定化材料进行了介绍。根据环境材料科学的发展前沿提出了污染场地环境修复功能材料的发展趋势,并总结了功能材料开发与应用中的一些问题。 相似文献
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铁碳微电解/Fenton法处理难降解化工废水的对比试验 总被引:1,自引:1,他引:0
采用Fenton氧化、铁碳微电解工艺处理难降解化工废水。采用Fenton氧化处理该废水,当进水ρ(COD)在5000mg/L、B/C为0.3左右时,COD去除效率在30%左右,B/C提高约0.05;采用铁碳微电解工艺处理该废水,研究了不同pH条件和介质(铁屑和铁块)对去除效果及产泥量的影响,结果表明:pH为3.0、反应时间3 h、采用铁块处理该废水为最佳条件,COD去除效率在40%左右,B/C提高0.080.1,绝干污泥产量约为1.2kg/t。通过对比试验发现,采用铁碳微电解的处理效果和经济性均优于Fenton氧化工艺。 相似文献
688.
Tong Huiyan Jiang Qianyi Zhong Xiaocong Hu Xingshuai 《Environmental science and pollution research international》2021,28(4):4209-4215
Environmental Science and Pollution Research - In the recent years, microplastics have attracted much attention as new emerging environmental pollutants. Previously, several studies were performed... 相似文献
689.
钟南才 《防灾科技学院学报》2007,9(1):15-17,28
本文认为,民主是一个政党健康发展的根本保证.而对"什么是民主","怎样建设和发展民主"的科学回答则是民主上述功能发挥的基本前提.民主既是对专制和独裁的否定,同时又是对建立在个人自由主义基础上的极端民主化和无政府主义的否定.我们必须在"科学发展观"这一基本理念的统领下进行包括扩大基层民主在内的民主政治建设-在扩大基层民主方面既不能徘徊不前,更不能搞"大跃进";既要整体推进,但又不能搞"一刀切";既要扩大和发展民主,又要讲求和兼顾科学与效率.只有把扩大基层民主置于"科学发展观"这一基本理念之上,才能有助于推进和谐社会建设. 相似文献
690.
关于小城镇产业发展问题的思考 总被引:12,自引:1,他引:11
小城镇建设与产业发展关系密切。研究小城镇必须研究小城镇的产业发展问题。本文分析了我国小城镇产业发展的现状,指出了小城镇产业发展存在的问题,并提出了小城镇产业发展的原则和对策。 相似文献