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排序方式: 共有1512条查询结果,搜索用时 15 毫秒
41.
燃煤电厂排放颗粒物中重金属形态的研究   总被引:27,自引:4,他引:27  
本文分析用模拟酸雨浸提和Tessier形态分离法,对燃煤电厂排放颗粒物中重金属形态进行了研究。结果表明,痕量金属绝大部分以稳定态存在,微米级飞灰中有较大活性的形态高于灰渣,煤燃烧高温条件使颗粒物中活性较大的形态含量减小。  相似文献   
42.
离子色谱法测定大气中的甲磺酸   总被引:7,自引:0,他引:7  
胡敏  陆昀  曾立民 《环境化学》2000,19(6):572-576
建立了以玻璃纤维膜-KB120气溶胶采样器采集大气中甲磺酸的采样方法;以0.1mmol·l-1H3BO3/0.1mmol·l-1 Na2B4O7为淋洗液的甲磺酸离子色谱分析方法.分析方法的精密度和准确度分别为5%和4%.并实测了青岛冬季大气气溶胶中MSA,SO2-4和NO-3的平均浓度分别为0.10μg·m-3,30.40μg·m -3和17.98μg·m-3.  相似文献   
43.
在选择最佳测定条件的基础上,对比了模拟酶蛋白结合物和HEMIN对过氧化物的测定效果。结果表明,HEMIN-BSA效果最好,其对过氧化物的荧光响应信号约是HEMIN的2倍,该物质在不改变激发和发射光谱的前提下可增强反应活性,提高反应灵敏度,使方法检测限降低至使用HEMIN时的1/3左右,最低线性值降至原来的1/5左右,同时,精度亦有所提高。  相似文献   
44.
Spatial distribution of chlorinated hydrocarbons [chlorinated pesticides (CPs) and polychlorinated biphenyls (PCBs)] and polycyclic aromatic hydrocarbons (PAHs) was measured in riverine and estuarine sediment samples from Pearl River Delta, China, collected in 1997. Concentrations of CPs of the riverine sediment samples range from 12 to 158 ng/g, dry weight, while those of PCBs range from 11 to 486 ng/g. The CPs concentrations of the estuarine sediment samples are in the range 6-1658 ng/g, while concentrations of PCBs are in the range 10-339 ng/g. Total PAH concentration ranges from 1168 to 21,329 ng/g in the riverine sediment samples, whereas the PAH concentration ranges from 323 to 14,812 ng/g in the sediment samples of the Estuary. Sediment samples of the Zhujiang River and Macao harbor around the Estuary show the highest concentrations of CPs, PCBs, and PAHs. Possible factors affecting the distribution patterns are also discussed based on the usage history of the chemicals, hydrologic condition, and land erosion due to urbanization processes. The composition of PAHs is investigated and used to assess petrogenic, combustion and naturally derived PAHs of the sediment samples of the Pearl River Delta. In addition, the concentrations of a number of organic compounds of the Pearl River Delta samples indicate that sediments of the Zhujiang river and Macao harbor are most likely to pose biological impairment.  相似文献   
45.
湖泊富营养化模型的研究进展   总被引:1,自引:0,他引:1  
湖泊的富营养化是全球普遍关注的环境问题之一.湖泊的富营养化模型是防治、修复和治理湖泊富营养化的重要决策工具.按研究的侧重点不同,将湖泊富营养化模型分为简单回归模型、水质模型、生态模型和生态-水动力水质模型,并分别回顾了四类模型的研究进展.最后指出湖泊富营养化模型的发展趋势,强调不确定理论、3S技术、耦合模型是今后湖泊富营养化模型研究的重点,应在此基础上建立通用的模拟、预测、评价和优化模型,为湖泊富营养化管理提供科学依据.  相似文献   
46.
Environmental Science and Pollution Research - Inappropriate farm management practices can lead to increased agricultural inputs and changes in atmospheric greenhouse gas (GHG) emissions, impacting...  相似文献   
47.
• US tin use decreases as the GDP value added by manufacturing sector increases. • Global and China’s tin use increases as the GDP added by manufacturing increases. • A sigmoid curve can fit the US tin use data well. • US tin use patterns is not due to the finite tin reserves or resources. • Policies, substitutions, etc. play key roles in the changing tin use patterns. Tin is of key importance to daily life and national security; it is considered an essential industrial metal. The United States (US) is the world’s largest economy and consumer of natural resources. Therefore, the analysis of historical tin use in the US is helpful for understanding future tin use trends in the world as a whole and in developing countries. Time series analysis, regression analysis with GDP or GDP/capita, and historical data fitted with logistic and Gompertz models are employed in this study. Historical tin use in the US shows three stages—increase-constant-decrease, as GDP per capita has increased. Tin use in the US is negatively correlated with the GDP value added by the manufacturing sector, while the use of tin worldwide and in China continues to increase along with the GDP value added by the manufacturing sector. Although a sigmoid curve can fit the US tin use data well, that use is not directly related to the limited tin reserves or resources. Rather, policies, economic restructuring, substitutions, new end-use markets, etc. have played key roles in the changing tin use patterns. This work contributes to understanding future tin use at both the global and national levels: tin use will continue to increase with GDP at the global level, but use patterns of tin at the national level can be changed through human intervention.  相似文献   
48.
太湖水体中5种有机磷农药混合物生态风险评价   总被引:2,自引:0,他引:2  
有机磷农药是一类广泛分布于我国水环境中的污染物,即使在水体中的污染水平处于规定“安全标准”之下,其联合暴露产生的风险仍有可能威胁水生生态安全。采用基于浓度加和模型与生物敏感度分布曲线的混合物风险商法,评价了太湖水体中敌敌畏、对硫磷、甲基对硫磷、马拉硫磷和乐果5种有机磷农药混合物产生的生态风险。结果表明:2003~2004年期间3个不同时期太湖水体中5种有机磷农药的混合物生态风险商(RQm )均大于1,有机磷农药混合物在2003~2004年期间对太湖水生生物构成了一定威胁。  相似文献   
49.
酸胁迫对铜藻早期生长阶段的影响   总被引:1,自引:0,他引:1  
为探究低pH胁迫对大型藻类早期生长的影响,以铜藻 Sargassum horneri 为研究对象,设置pH=3.5、4.5、5.5、6.5处理组和自然海水对照组,以不同处理时间分别对铜藻孢子和幼体进行胁迫实验。孢子实验中,于铜藻孢子附着前、后对其进行15、30、60、120 min的酸胁迫,以附着率和脱落率表征低pH对孢子附着的影响;幼体实验中,持续将铜藻幼体暴露于酸性条件下,以脱落死亡率表征pH对幼体的致死效应。结果显示,在短时间酸胁迫下,酸度对铜藻孢子附着的影响显著,附着率随pH值的下降而降低;胁迫时间对孢子的附着影响显著,附着率随胁迫时间的延长而降低,pH值与胁迫时间无交互作用;而当孢子已充分附着后,短期酸胁迫并没有显著影响孢子体的存活。在长时间酸胁迫下,与对照组相比,所有处理组铜藻幼体的存活率均显著降低。研究表明,低pH会对铜藻孢子、幼体的存活生长产生不利影响,并且这种影响在铜藻早期发育的不同阶段有所不同。  相似文献   
50.
This paper discusses the use of substance flow analysis (SFA) as a tool to support quantified research on urban drainage systems. Based on the principle of mass balance, a static substance flow model is established to describe and examine the routes and intensities of water, chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) for a representative hypothetical city (RH city) in China, which is a devised and scaled city using statistical characteristics of urban circumstances at the national level. It is estimated that the annual flux of water, COD, TN and TP through the urban drainage system in 2010 was 55.1 million m3, 16037.3 t, 1649.5 t and 209.7 t, respectively. The effluent of wastewater treatment plant (WWTP) was identified as the most important pathway for pollutant emissions, which contributed approximately 60% of COD, 65% of TN and 50% of TP to receiving water. During the wastewater treatment process, 1.0 million m3, 7042.5 t, 584.2 t and 161.4 t of the four studied substances had been transmitted into sludge, meanwhile 3813.0 t of COD and 394.0 t of TN were converted and emitted to the atmosphere. Compared with the representative hypothetical city of 2000, urban population and the area of urban built districts had expanded by approximately 90% and 80% respectively during the decade, resulting in a more than threefold increase in the input of substances into the urban drainage system. Thanks to the development of urban drainage systems, the total loads of the city were maintained at a similar level.  相似文献   
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