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Excessive input of nutrients such as nitrogen and phosphorus into natural water bodies is an escalating factor that leads to eutrophication.As a critical limiting nutrient for the growth of aquatic biomass,phosphorus is mainly from human activities of the socio-economic system.Hence,quantifying the pathway of phosphorus throughout the socio-economic system is essential for the selection of appropriate measures to mitigate phosphorus discharge.The study develops a framework for analyzing phosphorus flows in socio-economic at county which divides the life-cycle of phosphorus flow into four stages: extraction,fabrication and manufacturing,use,and waste management.Meantime,we subdivide the stage of use into five major subsystems: agriculture,large-scale livestock breeding,domestic breeding,rural consumption,and urban consumption.Furthermore,based on principle of mass conservation,we develop formulas for calculating phosphorus flows which is mainly expressed in three kinds: constant equations,dependent equations and balance equations.In addition,we apply our framework and calculation formulas to quantify the anthropogenic phosphorus flows of Hanshan County in 2008.Hanshan county located east of Chaohu Lake.Our data mainly come from questionnaire,face-to-face interviews,official statistics,published literature,and expert consultation.The data of phosphorus content of the products are collected from published literature and expert consultation.The data of phosphorus product consumption per capita are acquired through questionnaire and face-to-face interviews.The other data,such as planting area and rural and urban population,come from official statistics. The results show that,in 2008,the total input of phosphorus in Hanshan county is 5324 tons,of which,59% is imported from outside with purchased fertilizers.The total output of phosphorus in Hanshan County is 3023 tons,and 22% is exported outside.In terms of phosphorus loss,there was 1592 tons of phosphorus discharged into local surface water in Hanshan county,which primarily comes from agriculture(77%) and rural consumption(18%),and the other subsystems contribute only 5% of the total phosphorus loss into watercourses.Moreover,agricultural subsystem accounts for the largest proportion of the phosphorus input with the lowest phosphorus use efficiency(45%) due to excessive phosphorus loss.At the same time,intensive input of fertilizers in agricultural practices was identified as the most important source of phosphorus load on local surface water.Based on our above analysis,we propose that the eutrophication of local water bodies could be addressed by optimizing agricultural structure,promoting rational fertilization and scientific farming,encouraging the appropriate disposal of livestock manure,enhancing residents' environmental consciousness and improving the waste management system.Limitations of the methodology and data are also discussed.We will simulate and analyze the policies and control programs with the substance flow model and scenario analysis in future study.

Although prediction model AERMOD has been widely applied for atmospheric impact assessment in China and abroad, the considerable difficulty of getting the hourly surface meteorological data and upper data in one or more years hinders the development of atmospheric environment assessment in China. By coupling with relevant kernel (AERMOD, AERMAP, BPIPPRM) of AERMOD, AERSCREEN can capture the meteorological conditions and concentration results for the worst case without any input of meteorological data. In this paper, a comparison of atmospheric prediction on the flat terrain between AERMOD and AERSCREEN is made by setting several scenarios in condition of different underlying surfaces and source parameters. Then, a new method of atmospheric impact prediction without meteorological data based on AERSCREEN, as well as suggestions, is put forward in the end of the paper.