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101.
This paper deals with the absorption,accumulation and distribution of several heavy metals in Avicennia marina community at Futian Nature Reserve in Shenzhen。China.The results showed that:(1)the contents of Cu,Ph,Zn,Cd,Cr,Ni and Mn in the topsoil(O---30cm in depth)were 38.3,28.7,11.4,0.136,7 97,25.0 and 537 μg/g respectively;(2)there were significant differences in the contents of heavy metals in different fractions of Avicennia marina,and the content ranges were 1.8—13.8 for Cu,0.4—3.51 for Pb;3.4—69.5 for Zn,0.013—0.295 for Cd,0.28—0.73 for Cr,0.43—7.65 for Ni and 25一1552 μg/g for Mn;(3)The enrichment coefficient (weighted mean) of the plants to topsoil was Cd>Mn>Zn>Cu>Ni=Cr>Pb;(4)the accumulation amounts of seven elements in standing biomass of this community were 53.70,19.27,187.89,0.72,6.06,20.76 and 1631.17 mg/m2 for Cu,Pb,Zn,Cd,Cr,Ni and Mn respectively.The net retention amount in the community(1993)were 4.06,1.32,16.36,1.43,107.98 rag/(m2.a)for Cu,Pb,Zn,Ni and Mn,60.21 and 431.8Oμg/(m2.a)for Cd and Cr respectively;(5)the potential amounts of the elements which existed in the residues of soil surface in the community were 2.09,1.96,5.05,1.54 and 405.54 mg/m2for Cu,Pb,Zn,Ni and Mn,and which of Cd and Cr were 19.30 and 78.00 μg/m2,respectively. 相似文献
102.
This paper presents the trends of total ozone at Beijing and Kunming areas during the period of 1979 to 1989.The SBUV ozone vertical profile data and the periodic oscillation in upper ozone layers over Beijing area are also described.The results show that the variation of Beijing and Kunming per decade are about-5%and-1.5%.respectively. 相似文献
103.
A simple laboratory device which simulates environmental factors that affect N2O emission from soil has been constructed. It is convenient to use it to observe the N2O emission dynamics from soil cores while simulating some factors such as different fertilizer sources,management,temperature.and chemical inhibitors,etc.The detect limit was 2.5mg N2O-N m-2.s-1 with maxinlum error about 10%, so it could be used for agricultural soils It was found that fertilizer source,fertilizer management and native soil type were preliminarily important factors on N2O emission fluxes in some of our experiments. 相似文献
104.
The relationships for the rate of the pyritic wastestone weathering and leaching amount,surface area of the wastestone weathering,oxidant in the weathering system and the acidity of weathering solution were simulated.Jt was found that,on the basis of the logarithmic relationship between releasing amount of sulfur and leaching amount,the weathering rate of sulfide in the pyritic wastestone was changed exponentially with leaching amount.The relationships between the rate and weathering surface area of the wastestone and the rate and oxidant were exponential.It was indicated that there was scarcely relationship between the rate and acidity of the weathering solution. 相似文献
105.
The sediment quality mapping of Cu.Zn.Pb and Cd in the<20μm fraction of surface sedi.ments ofthe Le An River·Poyang Lake area clearly proves that the mining activities ofDexing Copper Mine and nearby smaller Pb—Zn mines have already polluted the aquatic system to some extent.Although poilution indices of the Poyang Lake sediments are still close to background values,first results from sediment cores point to a definite trend of gradually increasing contamination. 相似文献
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108.
1 概述我国城市污水处理事业起步较晚,近10年来才有了一定的发展。目前全国已建成城市污水处理厂80余座,年处理污水能力达12亿m~3。苏州市根据城市建设发展的需要,建设了3座污水处理厂,日处理能力达1.25万吨。对保护和改善环境发挥了积极作用污水处理厂的污泥处理是一个十分关键的环节,以往常被忽视,或处理不当引起二次污染。随着工业生产的迅速发展和城市规模的日益扩大,污水量也相应增加,污水处理中的污泥问题也更为突出。 相似文献
109.