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1.
The typical parameters of acid precipitation are evaluated in the forest of Vallombrosa (Tuscan Appennines) during the dry period 1988-89. Individual rain events (dry and wet deposition) were sampled in a clearing of the forest and below the canopy of an evergreen tree as well as a deciduous broadleaf tree.
In atmospheric precipitation the pH values usually vary around 4.4, with neutralization in the hot season due to calcareous material from distant sources. Relatively large concentrations of Pb and Cd are found in rain, but only in a small amount in canopy leachate. Aluminium, manganese and iron are more significantly washed off than Pb and Cd. 相似文献
In atmospheric precipitation the pH values usually vary around 4.4, with neutralization in the hot season due to calcareous material from distant sources. Relatively large concentrations of Pb and Cd are found in rain, but only in a small amount in canopy leachate. Aluminium, manganese and iron are more significantly washed off than Pb and Cd. 相似文献
2.
Fractionation of Cu, Pb and Zn in certified reference soils SRM 2710 and SRM 2711 using the optimized BCR sequential extraction procedure 总被引:4,自引:0,他引:4
Sequential extraction of metals from solid media is a common analytical tool used in environmental and exploration geochemistry. A number of procedures exist, but without harmonization and standardization, meaningful comparisons are tenuous without baseline data. A newly developed, standardized sequential extraction procedure (optimized BCR) was applied to two contaminated certified reference soils from Montana, US (SRM 2710 and SRM 2711) for Cu, Pb and Zn. Four operationally defined fractions were isolated, acid extractable, reducible, oxidizable, and residual (by aqua regia). Fraction-specific concentrations, percentages and recoveries for Cu, Pb and Zn were used to explore differences between the optimized BCR procedure and three other sequential extraction schemes with published data for SRM 2710 and 2711 (i.e. Tessier scheme, Geological Survey of Canada scheme and the original BCR scheme). Results indicate significant differences between the four schemes, even for schemes that are closely associated (i.e. the original and optimized BCR schemes). Order-of-magnitude fraction-specific concentration differences were observed, especially for Pb in the reducible fraction. Differences between schemes are worrisome because trends varied between metals, between fractions and between reference soils. These data reinforce the need for increased adoption of standardized sequential extraction procedures and further examination of different solid media. 相似文献
3.
酸雨对种子萌发影响的实验研究 总被引:1,自引:0,他引:1
采用PH值2.5、3.0、3.5、4.5的酸雨处理小麦种子,观察种子的萌发率、平均萌发天数和萌发势。结果表明:酸雨对种子的萌发率和平均萌发无显著影响,但对种子萌发势有显著影响。 相似文献
4.
钢铁冷锻加工中的磷化工序一般采用酸洗法去除毛坯上的氧化膜。现介绍用抛丸处理工艺替代酸洗方法,可以大幅度减少工业污染,降低生产成本,提高工艺质量。 相似文献
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6.
海洋气溶胶对沿海地区降水组成的贡献 总被引:2,自引:0,他引:2
以青岛地区为对象,对沿海地区大气气溶海洋因子对降水组成的贡献,进行了研究分析。结果表明,1)夏季受海洋影响要比冬季明显得多;(2)降水中主要的碱性物质,不论是夏季或冬季,99%来自大陆气溶胶,海洋的影响可忽略;(3)海洋影响的程度和离海边的距离有关,离海愈远,受海洋影响就愈小,离海愈近,受其影响就愈大。 相似文献
7.
氢氟酸的污染与防治 总被引:1,自引:0,他引:1
方慧萍 《石油化工环境保护》1997,(1):52-54
综述氢氟酸烷基化装置,运行过程中氢氟酸的危害,污染源的分析,防治措施及取得效果. 相似文献
8.
BP神经网络在降水酸度预测中的应用 总被引:5,自引:0,他引:5
本文利用南昌市城市大气中SO2、NOX、TSP等浓度数据及降尘数据建立了BP神经网络的降雨酸度预测模型,结果表明:BP神经网络的预测模型不仅能较好地反映致酸因素与降水酸度的相互关系,而且预测精度也高于多元回归等模型。 相似文献
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