The Research Of Heavy Metals Environmental Capacity In Main Soil Types Of Yellow River Delta

The environmental capacity is one of the basic problems in the research of environmental science,which used mathematical models to calculate the values in different environmental units or different materials,the results can provide favorable directive effects for the constitute of environmental standard,controlling and the target of management and the environmental impact review.With the development of environmental science,the classification of environmental becomes more detailed.According to the different environmental units,different styles of pollutants,different aims of evaluation,it has different assortment.The major characters of the environmental capacity include objectivity,stability,modifiability,finiteness and controllability.For the research of environmental capacity,the important development trend is the accurate quantitative description,especially for the formation of migration and transformation in environmental media and self-purification of various contaminants that part of the extra capacity calculation,need more detailed scientific research.In addition,according to the characteristics of different environmental units,it is also one of the main trends that how to grasp the regional characteristics,so make the results more meaningful.Soil is the direct source of grain crops for people life,the safety of the soil quality is very close to human health.With the development of econony,different kinds of pollutants transferred into the soil by different ways,which caused a serious menace to the soil environment.The land source,as a most basically component of an environment area,to use it reasonable or not,it will cause significant influence on the social economy and ecological environment.To research the soil environmental capacity can provide favorable application value for considering a soil environment standard,an irrigating water standard in farming,rational development and utilization of land source and the controlling of the amounts of pollutant.The Yellow River Delta has a large area of land to be developed,rich in land reserve resources.However,due to its special geographical location,the ecological environment is fragile,but with the development of economy,to development and utilize the sources of this place,the production of human life was not on the premise of sustainable development,which brings great influence to the local land sources allocation and soil health,then a serious of problems produced,such as the soil salinization,the lack of fresh water source and so on.So,this article chose the Yellow River Delta which is a representative area in Shandong Province to research the soil environmental capacity.We chose three major soil types in the area,saline soil,fluvo?aquic soil and paddy soil;seven major heavy metals include Cu,Zn,Pb,Cd,As,Hg,Cr to evaluate the environmental capacity.We used the existing mathematical models to calculate and statistic the results of environmental capacity.The data was obtained by relative experiments and referred from literatures and books.We calculated the static environmental capacity and the dynamic environmental capacity with background value and existing value respectively,then compared the differences,the results showed that:For the static environmental capacity,without considering the dynamic changes about the pollutant in soil,most of the heavy metals had higher environmental capacity in saline soil and fluvo-aquic soil,while the paddy soil is lower than them,showed remarkable or quite remarkable difference.Especially,the environmental capacity of Zn in saline soil and fluvo-aquic soil,it is 2.5 times higher than paddy soil,the environmental capacity of Pb is 1.5 times higher than saline soil and 6 times higher than paddy soil.The saline soil and fluvo-aquic soil occupies the most part of land source in Yellow River Delta,controlling the content of heavy metal.in this two soils is very important,however,for paddy soil,controlling the input and administration is the case measure.The value of the static environmental was affected by the original 'value of heavy metals in soil,the physic-chemical properties and the properties of heavy metals themselves.Therefore,the results of the static environmental have:important significance to evaluate the simple soil support pollutant ability and the absorbed ability of heavy metals.For the dynamic environmental capacity,considering the dynamic changes about the pollutant in soil,we added the years in the calculation,the results showed that:with the increase of the years,the value of dynamic environmental capacity became quite stable gradually,which showed the regular of dynamic balance,when the years decreased,the average dynamic annual capacity increased,but the whole capacity decreased,while when the years increased,it showed the opposite phenomena.We chose the results of 10 years of the dynamic environmental capacity to analysis and compared with the results of the static environmental.There are obviously differences between them,the environmental capacity of Cd,Hg in paddy soil showed the obviously increasing,which confirmed that for the unstable and easily element,the extra environmental capacity brought by the dynamic changes in soil is an important part in the whole environmental capacity,which used to evaluate the soil conditions.On the whole,the saline soil and fluvo-aquic soil still hold advantage on the land source,how to improve the extra environmental capacity which produced by the motion of heavy metals in soil is a case problem for this two soils,then make the soil clean better,producing excellent land source and optrimizing the use of land source.For the paddy soil,we should supervised the concentration of heavy metal in crops,underground water and the soil in deep layer,to prevent the second pollution and the threaten to human health.The dynamic environmental capacity was mainly affected by the properties of heavy metal themselves and the different dynamic progress in soil.The results of the dynamic environmental capacity can better reflected the ability of support pollutant for an area,also,can evaluate more extensive aspects.For the static environmental capacity,the value based on the background and existing showed some differences,so different evaluate scopes and targets should choose different original values.However,the dynamic environmental capacity was not affected by the original values,especially with the years increased,the values were become equal gradually,therefore,the mathematic model of dynamic environmental capacity was more flexible in practical application.