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891.
以铁岭市柴河水库上游集水区域为研究对象,利用铁岭市柴河堡水文站降雨时节实测的暴雨径流数据、泥沙数据、污染物浓度数据进行分析,侧重研究降雨时节暴雨径流量与主要污染物浓度及污染物瞬时流失量之间的关系,以期为柴河流域农业非点源污染控制提供参考。研究结果表明:暴雨期内,非点源污染物浓度及瞬时流失量与径流峰值几乎同步出现,它们之间存在着非常密切的关系。 相似文献
892.
893.
894.
测定了竹炭对微污染水源水中CODMn,UV254,UV410的去除效果,研究了竹炭粒径、竹炭用量、吸附时间、溶液pH值对竹炭吸附特性的影响,并由正交试验确定出竹炭去除水中CODMn,UV254,UV410的最佳吸附条件。研究表明,粒径越小,竹炭的吸附效果越好;竹炭用量为100mg、吸附时间为1h时,竹炭对各指标去除率最高;弱酸条件对竹炭对各指标的吸附最有利,当pH值=4时竹炭对各指标的去除率最大;正交试验确定出动态吸附最佳操作条件为:竹炭粒径为100~200目,质量为100mg,振荡吸附1h,原水pH值为4。 相似文献
895.
896.
897.
北京市空气质量时间变化特点分析 总被引:2,自引:0,他引:2
本文以北京市为例,对北京市2000—2004年的空气质量日报(包括首要污染物,污染指数,空气质量级别以及空气质量状况等)进行分析研究,得出其年变化和月变化的特征以及中重度污染日的分布特征,结果表明,从2000年到2004年中,北京市2001年和2002年的污染颇为严重,其平均的污染指数为113和112。北京市一年中,冬季污染较为严重,尤其是12和1月两个月份,这与北京市的能源结构是密切相关的。2001年是中重度污染日最多的年份,为23天;中重度污染日持续天数最多的是8天,是在2002年4月份;中重度污染多发生在3月份、4月份以及11月份,北京市的首要污染物是可吸入颗粒物。 相似文献
898.
Combined fluorescence and electrochemical investigation on the binding
interaction between organic acid and human serum albumin 总被引:1,自引:1,他引:0
Human serum albumin (HSA) is a plasma protein responsible for the binding and transport of fatty acids and a variety of exogenous chemicals such as drugs and environmental pollutants. Such binding plays a crucial role in determining the ADME (absorption, distribution, metabolism, and excretion) and bioavailability of the pollutants. We report investigation on the binding interaction between HSA and acetic acid (C2), octanoic acid (C8) and dodecanoic acid (C12) by the combination of site-specific fluorescent probe, tryptophan intrinsic fluorescence and tyrosine electrochemistry. Two fluorescent probes, dansylamide and dansyl-L-proline, were employed in the displacement measurement to study fatty acid interaction with the two drug-binding sites on HSA. Intrinsic fluorescence of tryptophan in HSA was monitored upon addition of the fatty acids into HSA. Electrocatalyzed response of the tyrosine residues in HSA by a redox mediator was used to investigate the binding interaction. Qualitatively, observations made by the three approaches are very similar. HSA did not show any change in either fluorescence or electrochemistry after mixing with C2, suggesting there is no significant interaction with the short-chain fatty acid. For C8, the measured signal dropped in a single-exponential fashion, indicative of independent and non-cooperative binding. The calculated association constant and binding ratio is 3.1×106 L/mol and 1 with drug binding Site I, 1.1×107 L/mol and 1 with Site II, and 7.0×104 L/mol and 4 with the tryptophan site. The measurement with C12 displayed multiple phases of fluorescence change, suggesting cooperativity and allosteric effect of C12 binding. These results correlate well with those obtained by the established methods, and validate the new approach as a viable tool to study the interactions of environmental pollutants with biological molecules. 相似文献
899.
Fluidized pellet bed (FPB) has been successfully applied in water and wastewater treatment. However, the removal mechanism of
contaminants especially the soluble ones, is still unclear. This study aimed to evaluate the e ectiveness of FPB reactor for removing
soluble contaminants from synthetic wastewater. By only coagulation through jar test operation with addition of polyaluminium chloride
(PACl) as primary coagulant and polyacryamide (PAM) as coagulant-aid, the removals of soluble chemical oxygen demand (COD),
total phosphorus (TP), and NH4
+-N were found to be only 2.2%–7.5%, 5.7%–25.5%, and 9.9%–18.5%, respectively. However, by FPB
operation under the same dosage of coagulants, these values increased to 82.7%, 37.2%, and 50%, indicating that the formation of
pellets in the FPB e ectively enhanced the removal of soluble contaminants. By careful comparison of the settleablility and filterability
of the pollutants after coagulation, the originally soluble contaminants could be divided into three groups, namely: (1) coagulated-andsettleable,
(2) coagulated-but-nonsettleable, and (3) uncoagulable. It was found that not only the first two groups but also a large part of
the third group could be e ectively removed by FPB operation. However, the mechanism for the removal of the uncoagulable pollutants
by FPB operation still needs further investigation. 相似文献
900.
Two plant populations of Phragmites australis and Typha orientalis grown in gravel and sediment substrate were studied to assess their capabilities for purifying polluted water in Taihu Lake, China. The substrate displayed most significant effects on the suspended matter (P < 0.01), with the reduction of 76%-87% and 52%-63% for P. australis, and 83%-86% and 45%-62% for T. orientalis in gravel substrate and sediment substrate, respectively. Both species and substrates significantly decreased the N and P conc... 相似文献