Knowing the development stage of urban agglomerations is a precondition for studying or planning and constructing it. Taking into consideration that the fact the standard of dividing the development stage of urban agglomerations isn't unified for the academy, and by drawing lessons from the domestic and international methods of dividing development stages of urban agglomerations and imitating the regulation of life growing up, the development stages of urban agglomerations are divided into four stages, those are the rudiment development stage, the speediness development stage, the tend towards maturity stage and the maturity development stage. The features of the different development stages of urban agglomerations are also generalized. Based on the features of the different development stages of urban agglomerations, the index system and the standard of dividing the development stages of urban agglomerations are designed. Finally, Changzhutan urban agglomeration and Pan Changzhutan urban agglomeration as cases are evaluated by the methods of fuzzy comprehensive evaluation and analysis of hierarchy procedure. The result of evaluation shows that Changzhutan urban agglomeration has entered the speediness development stage, but Pan Changzhutan urban agglomeration is still in the rudiment development stage.

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Nonpoint source (NPS) pollution of particulate phosphorus (PP) has recently become an important environmental concern in Three Gorges Reservoir. This study aims to identify the contributing zones of sediment and PP pollution in the upstream watershed of Three Gorges Reservoir and quantify the pollution by simulation method. Firstly, a mathematical model of annual sediment yields was proposed based on the Universal Soil Loss Equation（USLE）. The proposed model introduced a coefficient according to the influence of hydrology condition and human activities on sediment yield. The spatial and temporal distribution of sediment delivery ratio (SDR) in the model was got by topography index interpolation method. Then, an annual load model of PP pollution was established on the basis of the sediment model. The PP pollution in 1990~2006 was simulated by the model integrated with GIS. The simulation results show that subbasins of middle and lower reaches of Jinsha River, Yalong River and Dadu River are the main sources of the NPS pollution of PP, and the Jialing River subbasin has a relatively low degree of soil and particulate nutrients loss due to the “key erosion prevention project in the upper Yangtze River” program began in 1989. The PP pollution imported into the reservoir has declined since the implementation of the soil loss prevention program. Annual average load in the last five years is 16 482 t/a, which have reduced by about 37 % compared with that of in 1990.

Law of preventing and controlling polluted soil in Russia has its own features.The author concluded seven features of the law construction and puts forward the necessity and urgency of constructing Law of Preventing and Controlling Polluted Soil in China according to the present situation of the soil pollution in China.We can conclude that it is important to construct specialized Law of Preventing and Controlling Polluted Soil in China，establish the law concept，set up the specific standards of soil protection，establish the system of polluted soil predicting and repairing，strengthen the managing system of national supervision and permission on soil，emphasize the system of environmental evaluation and information opening and enlarge citizens' rights of public participation and so on.

In order to find out whether methylmercury concentrations will increase by building new reservoirs,this study concerns two new reservoirs (Hongjiadu and Suofengying Reservoirs) built in Wujiang River in Guizhou Province.Methylmercury concentrations of different seasons in the water columns about these two reservoirs were determined by distillationethylation GCCVAFS technique,the minimum level has been established as 0.009 ng/L.Influences on the distribution of Methylmercury from water quality parameters and the characteristic of methylmercury in the water columns were discussed.The results were as follows：For Hongjiadu reservoir,in summer total methylmercury concentrations averaged 0.11 ng/L,in autumn averaged 0.08 ng/L,and in winter,averaged 0.10 ng/L;For Suofengying reservoir,in summer total methylmercury concentrations averaged 0.11 ng/L,averaged 0.07 ng/L in autumn,and averaged 0.09 ng/L in winter.The results showed that methylmercury concentrations were relatively low in the water columns,and below the limits for Chinese environmental quality standards.Methylmercury levels were comparable to data reported in other uncontaminated reservoirs.It indicated that methylmercury concentrations in the water were no change with depth.In summer the methylmercury concentrations were higher than in autumn and winter,as a result of higher temperature and more rainfall.At the same time,low methylmercury levels may be due to a low concentration of organic matter in submerged soil and other environmental factors (eg.higher pH concentrations and lower DOC concentrations).Lower mercury methylation was expected in these two reservoirs.With the development of reservoir,it is possible that the methylmercury concentrations will increase due to autochthonous and extraneous organic materials,and methylmercury may be released due to thermal stratification.But this was not confirmed.

The compositions of sulfur isotopes were investigated in cascade reservoirs with different running ages (Hongjiadu Reservoir, Dongfeng Reservoir and Wujiangdu Reservoir) along Wujiang River. Water samples in the front of dams were collected along water column, and other river water samples were collected at 0.5m below water surface in July, 2007. The sulfur isotopic compositions (δ34S) along water column varied from +0.3‰ to +3.1‰ in Hongjiadu Reservoir, -7.5‰ to -5.5‰ in Dongfeng Reservoir, and -4.3‰ to -0.6‰ in Wujiangdu Reservoir, respectively. The δ34S in the release water of these three reservoirs were -0.7‰, -6.8‰, and -2.9‰, respectively. The results indicate that the changes in sulfur isotopic compositions mainly reflect the biogeochemical processes and the different sources of sulfur entering into reservoirs. Sulfur isotopic compositions in surface water and along water column showed a variation in different reservoirs. The δ34S in surface layer was controlled by the sulfur isotopic compositions of the input water, while the δ34S along water column decreased with the increase in depth, reflecting an influence of biological function and organic sulfur oxidation.

Water samples were monthly collected in inflows and outflows of cascade reservoirs in Wujiang River from January to December in 2006.Total mercury and methyl mercury concentrations were analyzed by cold vapor atomic fluorescence spectrometry and aqueous phase ethylation,GC separation,and CVAFS detection.The results were as follows:(1) Annual volumeweighted mean concentrations of total mercury were 317 and 2.34 ng/L,and methyl mercury concentrations were 014 and 0.18 ng/L in inflows and outflows,respectively.There were different mercury distribution characteristics in inflows and outflows of different reservoirs.(2) Total mercury concentrations in inflows were significantly lower than those in outflows,and showed an obvious seasonal variation in Puding and Hongjiadu Reservoir which was the first cascade reservoir in Sancha River and Liuchong River,respectively.However,markedly seasonal variations of methyl mercury were observed in outflows,and their concentrations were obviously higher than those in inflows only in older reservoirs (Puding Reservoir,Dongfeng Reservoir,Wujiangdu Reservoir).(3) Correlation analysis showed total mercury and methyl mercury concentrations in inflows were influenced by suspended matter,and their correlation with water volume varied with the location of reservoir.There was significant positive correlation in the upstream Puding and Hongjiadu reservoirs,and negative correlation in other reservoirs.

This study investigated the water chemistry of Wujiangdu Reservoir and its response to river damming.Results showed that major ionic chemistry of the reservoir dominated by HCO-3,SO2-4,Ca2+ and Mg2+,which account for about 90% of the total solutes in the water.It is concluded that limestone weathering,among silicate rock and evaporation weathering,are the most important controls on the water chemistry.The reservoir showed clear temperature stratification,and hence induced different chemical composition of major ions in the water of different water layers.Accordingly,dissolved components appeared different distribution characteristics along the water column.Si and Chlorophyll showed a negative correlation with each other in the vertical profile,due to biological function such as algal absorption.Concentration of HCO-3 decreased from surface water to 30 m in depth and then increase downwards,controlled by both photosynthesis and organic decomposition.River damming and the ways of water discharge of the reservoir can change the water chemistry of the reservoir and discharged water.In Pianyan River and Xifeng River Ca2+,SO2-4,HCO-3 Mg2+,K+,Na+ and Cl- have contributions to Wujiangdu Reservoir.Fish feeding,sewage inputs,fertilizer use and acid rain deposition are the possible contaminant sources for the reservoir water.

The study investigated the phosphorus retention effects of cascade reservoirs of Maotiao River in summer,which had been entirely exploited by 1960s.In order to find out the rules of phosphorus' retention effects,the water samples in the front of the dams by layers and outflow water of each reservoir were collected in cascade reservoirs in Maotiao River from July to September,2007.The total phosphorus and dissolved PO4P were analyzed in the laboratory.Results showed that the changes of total phosphorus are similar to dissolved PO4P in each reservoir,while the concentrations of dissolved PO4P and total phosphorus in release water were higher than that of their surface water.The concentrations of phosphorus in Hongfeng and Baihua reservoirs were higher than the other reservoirs，the P concentration was gradually reduced from upstream to downstream.Meanwhile,this characteristic was similar to the index of eutrophication.As Maotiao River's concerned,the exploitation of cascade reservoirs do have a certain retention effects on phosphorus.

In order to make clear that what kind of impacts the cascade reservoirs play on the nitrogen biogeochemistry circle in the river, we sampled water by different layers in front of the each dam and outflow water in the cascade reservoirs of Maotiao River, Guizhou Province, Southwest China. The water chemistry of the cascade reservoirs is discussed in terms of the physical and chemical parameters, together with N2O distribution in summer. The results indicate that discontinuity layers of temperature plays an important role in production and distribution of N2O in reservoirs of Maotiao River. The N2O distribution in the layer above the SDL (secondary discontinuity layer) in the four cascade reservoirs is dominated by nitrification, while between the SDL and PDL (primary discontinuity layer) is controlled by both of nitrification and denitrification. As two main processes that affect the production of the N2O, nitrification and denitrification change the distribution of N2O in cascade reservoirs. The contents of N2O in reservoirs are higher than that in the atmospheres. This suggests that high contents of the N2O in the reservoir are the N2O source of the atmosphere. However, N2O contents decrease at depth below 15 m with low contents of DO indicates that denitrification produced N2 by consuming a large part of N2O. The water discharge from bottom of cascade reservoirs along Maotiao River released large amount of N2O into atmosphere, which should be taken into account for improving environmental protection of waters in cascade reservoirs when hydroelectric power will be developed.

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