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991.
Distribution and contamination assessment of heavy metals in sediment of the Second Songhua River, China 总被引:2,自引:0,他引:2
The Second Songhua River was subjected to a large amount of raw or primary effluent from chemical industries in Jilin city
in 1960s to 1970s, resulting in serious mercury pollution. However, an understanding of other trace metal pollution has remained
unclear. The objective of this study was to investigate trace metal contamination in the sediment of the river. Bottom sediment
samples were taken in the river between Jilin city and Haerbin city in 2005. An uncontaminated sediment profile was taken
in the Nen River at the same time. Total concentrations of Al, Fe, Mg, Ca, K, Na, Ti, Mn, V, Sc, Co, Cu, Cr, Ni, Pb and Zn
in the sediment samples were measured by ICP-MS or ICP-OES, following digestion with various acids. Concentrations of Co,
Cu, Cr, Ni, Pb and Zn in the surface sediments were 5.1–14.7, 18.5–78.9, 2.4–75.4, 7.2–29.0, 13.5–124.4, and 21.8–403.1 mg/kg,
respectively, generally decreasing along the course of the river from Jilin city to Haerbin city. Background concentrations
of trace metals were reconstructed by geochemical normalization to a conservative element scandium. Results showed that concentrations
of Co, Cr, and Ni in the sediment were generally only slightly higher than or equal to their background values, while concentrations
of Cu, Pb, and Zn in the some sediment samples were significantly higher than their background values. In detail, the sediment
at Jilin city was moderately contaminated by Cu, and the sediment of the Second Songhua River was moderately contaminated
by Pb and Zn. The top layer (0–10 cm depth) and bottom layers (30–46 cm depth) of one sediment profile at Wukeshu town were
generally moderately polluted by Pb and Zn. Synthetically, the surface sediment in the studied river section was classified
as natural sediment without ecological risk by the sediment pollution index (SPI) of Cu, Cr, Ni, Pb and Zn. Only the 30–45 cm
depth of the sediment profile at Wukeshu town was classified as low polluted sediment by the SPI of these metals, recording
a historical contamination of the river in the 1960s to 1970s. This buried contamination of trace metals might pose a potential
risk to water column under disturbance of sediment.
Foundation item: The National Basic Research Priorities Program of China (2004CB418502) 相似文献
992.
关于旅游城市化问题的初步探讨——以长江三角洲都市连绵区为例 总被引:12,自引:0,他引:12
城市化发展的动力带动 ,城市旅游资源的富集 ,人口、经济的集聚与扩散 ,旅游供需关系的结合 ,旅游者对城市旅游目的地的选择行为 ,政策的导向 ,旅游业的发展和交通设施的完善等因素 ,导致了旅游城市化现象的产生。以长江三角洲都市连绵区为例 ,分析了旅游城市化进程中还存在发展思路不明 ,破坏旅游景观和生态环境 ,旅游规划与城市规划、城市发展不相适应 ,人口管理比较混乱 ,用地功能分区不明显 ,土地资源浪费严重等问题。提出了旅游城市化的发展对策 相似文献
993.
Distribution and migration of 95Zr in a tea plant/soil system 总被引:3,自引:0,他引:3
(95)Zr is a primary radionuclide in the radioactive liquid efflux from a pressurized water reactor and one of the main radionuclides released after nuclear accidents. The fission yield of (95)Zr is as high as 6.2%, however, its environmental behavior has not been well documented. An experiment was conducted to evaluate the accumulation and distribution of (95)Zr in a tea plant/soil system. (95)Zr was accumulated primarily in the trunk of tea plants after being taken up from the soil. The radioactivity concentration of (95)Zr in the trunk increased slowly with time, then it reached a dynamic equilibrium 14 days after application. The radioactivity concentration of (95)Zr in the other parts of the tea plant was very low; only slighter greater than the detection limit. The results indicated that (95)Zr was not readily translocated in the tea plant. About 98.9% of applied (95)Zr was found to concentrate in the upper 5 cm layer after being sprayed onto the soil surface. The results indicated that (95)Zr could not readily move downwards with percolating water due to strong adsorption to surface soil. 相似文献
994.
Indicators to distinguish between fecal coliforms of human and animal origin were investigated in water from storm sewer outfalls to a coastal lake during wet and dry weather. The ratio of fecal coliform relative to fecal streptococci count was used as the microbiological indicator. Concentrations of human-activities originated caffeine, anionic surfactant, fluoride, and fluorescence whitening agent (FWA) were used as chemical indicators. The ratio of fecal coliform to fecal streptococci ranged from 0.2 to 3.0, during wet weather making it difficult to interpret the origin of fecal pollution. However, concentrations of caffeine, anionic surfactant, fluoride, and FWA in storm water outflow during wet weather were much higher than those in the lake water during dry weather, indicating the presence of human waste at storm water outfall. Strong correlation between fecal coliform counts and chemical parameter values further indicated the human contribution to the fecal coliform count. In addition, a strong correlation among the chemical parameters suggested that only one of them is needed as chemical tracer to detect the presence of human input. 相似文献
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Adsorption of Pb and Cd in the presence and absence of organochlorine pesticides (OCPs) on natural surface coatings (NSCs), which were collected in the Nanhu Lake in Changchun, China, was measured in order to investigate the effect of the OCPs on the adsorption of heavy metals on the NSCs. Adsorption of Pb/Cd was carried out under controlled laboratory conditions (mineral salt solution with defined species, ionic strength 0.05 mol/l, 25 degrees C and pH 6.0) with initial Pb and Cd concentrations ranging from 0.2 to 2.5 mol/l. The classical Langmuir adsorption isotherm was applied to estimate the equilibrium coefficients of the adsorption of Pb and Cd on the NSCs. Adsorption interference between Pb/Cd and the OCPs on the NSCs indicated that the adsorption of Pb/Cd on the NSCs was influenced by the OCPs, and competitive adsorption between Pb and the OCPs was observed while adsorption of Cd was enhanced by addition of the OCPs. Adsorption data fit the Langmuir isotherm well for the NSCs treated with the OCPs at different equilibrium concentrations. The results showed that the amount of adsorbed Pb decreased by more than 40% while the amount of adsorbed Cd increased by over 60% with an increase in the initial concentrations of the OCPs ranging from 0 to 5.0 microg/l and that adsorption of Pb/Cd on the NSCs was strongly affected by the OCPs. This preliminary study highlights the importance of the OCPs on the NSCs in controlling the transport, fate, biogeochemistry, bioavailability and toxicity of trace metals in aquatic environments. 相似文献
1000.