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661.
662.
Y.M. Han S.C. Lee J.J. Cao K.F. Ho Z.S. An 《Atmospheric environment (Oxford, England : 1994)》2009,43(38):6066-6073
A previous study on PM2.5 carbonaceous aerosols measured with the thermal optical reflectance (TOR) method in fourteen Chinese cities is extended by subdividing total EC into char-EC and soot-EC. Average char-EC concentrations show great differences between the fourteen cities and between winter and summer periods, with concentrations of 8.67 and 2.41 μg m?3 in winter and summer, respectively. Meanwhile spatial and seasonal soot-EC variations are small, with average concentrations of 1.26 and 1.21 μg m?3 in winter and summer, respectively. Spatial and temporal distributions of char-EC, similar to EC, are mainly influenced by local fuel consumption, as well as the East Asian monsoon and some meteorological factors such as the mixing height and wet precipitation. The small spatial and seasonal variation of soot-EC is consistent with its regional-to-global dispersion, which may suggest that soot carbon is not local carbon, but regional carbon. Char-EC/soot-EC ratios show summer minimum and winter maximum in all cities, which is in good agreement with the difference in source contributions between the two periods. As OC/EC ratio is affected by the formation of the secondary organic aerosol (SOA), char-EC/soot-EC ratio is a more effective indicator for source identification of carbonaceous aerosol than previously used OC/EC ratio. 相似文献
663.
664.
漂浮植物塘协同处理农村分散生活污水研究 总被引:3,自引:1,他引:2
通过实验考察了漂浮植物塘对经模拟化粪池简易处理的农村分散生活污水的深度净化效果,结果表明:水葫芦、大薸、聚草塘对上述污水均具有良好的净化效果,水葫芦塘对TP的去除效果最好,大薸塘对TN和NH+4-N的去除效果最好。当水力停留时间为20 d时,3种漂浮植物塘的出水污染物含量可低于GB/T 18921-2002观赏性景观环境用水河道类标准。在南方农村宅沟园河内种植漂浮植物是构建农村实用生活污水收集处理系统、控制农村生活污水对河道污染的一种有效措施。 相似文献
665.
Organotin pollution in China: an overview of the current state and potential health risk 总被引:1,自引:0,他引:1
In recent years, considerable amounts of organotin compounds have entered the environment due to the wide industrial applications in China. Organotins were found in various environmental media. An overview of organotin contamination and distribution in China from various environmental samples, including waters and sediments, is presented to better understand the current state of organotin pollution in China and to improve environmental monitoring and management of organotin contamination. Exposure to organotin contaminated water and sediments induces accumulation of organotins in molluscs and biological effects such as imposex. Potential harmful effects on human health may also result from consumption of contaminated seafoods. Detailed information on distribution, impacts and assessment of risk to human health and marine ecosystems is discussed and monitoring of TBT using biomarkers is described. This review highlights the serious organotin contamination of coastal cities in China and emphasizes the need for long-term monitoring and the development of an effective regulatory program. 相似文献
666.
聚苯乙烯基硫代磺酸钾树脂对水中卤代物的选择性结构分析 总被引:5,自引:0,他引:5
本文用聚苯乙烯基硫代磺酸钾树脂为选择性试剂与水中卤代物作用,排除水体中其它化合物对结构分析的干扰,采用动态恒温柱法及C-18柱富集法作为该反应发生的途径,结果表明:前一种途径的检测结果由样品反应活性决定,而后者检测结果还受到萃取率的影响,两种方法均可达到10-20mg·l^-1的检测水平。 相似文献
667.
Selenium geochemistry of paddy soils in Yangtze River Delta 总被引:12,自引:0,他引:12
Selenium (Se) content both in total and bioavailable forms were very low (25-35 and 9.5 micrograms/kg, respectively) in waterlogged paddy soils in the central Yangtze River Delta. This was due to changes in geochemistry and the inherent properties of the parent materials of these lowland paddy soils. The very low Se content (23 micrograms/kg) in the parent material resulted in low total Se content in the soil. The main chemical changes under long-term waterlogged conditions are depletion of molecular oxygen, decrease of redox potential, and reduction of Fe (III) to Fe (II) and SeO3(2-) to Se0. This led to low availability of Se in soils, and subsequently low Se content (29 micrograms/kg) in brown rice grain produced in this region. It has been suspected that low Se content in staple food might be one of the major reasons for a high infection rate of the intestine and stomach cancers and the higher death rate caused by these diseases in the region. Foliage spray of Na2SeO3 at early heading stage of rice plant growth improved the Se content of brown rice grain, hull, and straw, and would improve human and animal health. 相似文献
668.
通江湖泊的渔业意义及其资源管理对策 总被引:21,自引:3,他引:21
长江中、下游的江湖复合生态系统包含有河流和湖泊两个环境单元。其中的鱼类群落由河海洄游鱼类、江湖洄游鱼类、河流鱼类和定居性鱼类等4个生态类群组成,尤以江湖洄游鱼类对这一特殊的生态环境形成了良好的适应,因而种群数量繁盛,从渔业的角度看,水利工程造成的江湖阻隔削弱了通江湖泊的生态功能,成为导致鱼类资源下降和种类结构改变的主要原因之一。当前应从控制捕捞、人工增殖和恢复生态环境结构等方面着手进行资源管理,确 相似文献
669.
670.