| The serious shortage of water resources in our country, especially in the arid and semi arid areas in northern, sewage irrigation has a special significance, the most township and rural which close to river have the habit of use of water for irrigation. The use of water for irrigation can not only ease the shortage of water resources situation, also can bring certain N, P and organic matter to soil and crop, increasing crop fertilizer source. Due to the unreasonable sewage irrigation has caused a series of environmental problems and agriculture problem, heavy metal pollutants in wastewater and some organic pollutants have the characteristics of stability,refractory and persistence,will cause harm to human body health.The effect of sewage irragation on soil,crop and human health has become one of the hot spot in the current.Regard sewage irrigated farmland in Linfen section of Fen Riv er as the research object, through field work and indoor test, obt ained the the physical and chemical properties and heavy metal c ontent data of the farmland of sewage irrigation area in Linfen se ction of Fen River, and on the basis of using of SPSS software an d using correlation analysis and factor analysis analyze the sourc es of pollutants; Using the cumulative index,potential ecologicalrisk index, the single factor pollution index and the comprehensive pollution index to research the comprehensive pollution assessment of soil in the area; Using the Arcgis software to descrip thespatial distribution characteristic of heavy metal content and physical and chemical properties.The main results were as follows:(1) Soil samples in the study area, the content of total nitrogen,available phosphorus,organic and rapidly-available potassium ofsome sample point have significant spatial differences difference,shows that its affected by human activities; variation coefficient ofpH is small, and three smaller regional differences, that is influencedby soil parent material and soil formation. Sewage irrigation andwater irrigation has obvious differences on soil nutrient accumulation(2) The results of the content of soil heavy metals characteristicsin the study area showed that, sewage irrigation farmland soil has avariety of heavy metal accumulation, but different levels in Linfensection of Fen River. In addition to Cr, Ni, the average content ofother heavy metals exceed the soil background values in ShanxiProvince, but the average contents of nine kinds of heavy metals arenot meet the limit of the secondary standard of national soilenvironmental quality.(3) using the factor analysis method to analysis the source ofheavy metals of surface farmland soil of sewage irrigation in Linfen section of Fen River,the result show that involved nine typesof heavy metal pollution can be divided into three categories: natural causes, industrial pollution, agricultural pollution. Therefore the local government and farmers should fundamentally control th e soil pollution combined with the source of heavy metal pollution, improving the farmland soil environment quality of irrigation area in Linfen section of Fen River.(4) Base on cumulative pollution index method, the soilenvironment of sewage irrigation in Linfen section of Fen River belongto no and intensity pollution, the enrichment of Cd, Pb and Hgpollution level is higher; According to potential ecological harm index,the soil environment is exist intensity pollution hazards,including Hgpollution hazard is most serious.(5) Based on single factor pollution index method, the soilbackground values in Shanxi Province as the evaluation standard,many kinds of heavy metal elements have a certain degree ofpollution,incuding the pollution of Hg，Cd, Pb is most serious. Basis onnational secondary standard of soil environmental quality, the soil inthe study area in a clean state as a whole, part of the element has asmaller degree of pollution. The comprehensive pollution indexshowed that if based on soil background values in Shanxi Province,the area suffered serious soil pollution; If use the national soilenvironmental quality second criteria to evaluate, the farmland soil inthe study area is still in the alert range, and not cause certain effectson the soil organisms and human life,but people should attach greatimportance.(6) The space difference analysis results of soil physical andchemical properties, content of heavy metal element of sewageirrigation farmland in Linfen section of Fen River show that due to thesoil parent material and unreasonable matter of production and livingof human,the degree of heavy metals pollution in sewage irragation is various,the sample points with more inflience factors have thecharacteristics of high content of the physical and chemicalproperties, severe pollution, diversification pollution. |
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