| As urbanization and population growth, land resources is facing huge pressure, people’s impact on the environment is more and more big, people to relationship became more and more complex.This may cause the soil pollution, not only can lead to serious ecological threat also affect people’s health.Especially in the city, because of the population live, all kinds of industrial pollution, waste water, waste gas is more likely to affect human health.Therefore, the urban soil environmental monitoring has become one of the important contents of today’s environmental science research.On urban soil environment monitoring in addition to the chemical method, biological repair, environmental magnetism due to its fast, does not destroy samples, the advantages of convenient as a new method of new urban soil pollution.Environmental magnetism principle is measuring soil, sediment, rocks and natural material such as atmospheric dust from human activity to produce various magnetic parameters of magnetic materials, so that the environment change information was extracted.To understand the impact of human activities on the environment in the process of natural, predict long-term environmental change trend.Can reveal human activities in the process of urbanization, industrialization on the quality of the soil.Based on soil of Shanghai city as the research object, this paper adopts the statistical method to the study area of soil magnetic susceptibility and frequency magnetic susceptibility spatial characteristics is analyzed, at the same time with the study area soil Cu, Cr, Mn, Pb, zinc and Fe, the6kinds of heavy metal element content, soil particle size and spatial distribution characteristics of organic matter, explore the spatial relationship between them, by studying the main conclusions are as follows:1, Sample belt from downtown xuhui district and minhang district to urban fringe area fengxian area, spatial distribution of soil magnetic susceptibility has "high-low-high" characteristics, the minimum value in fengxian,9.802X10-8/m3kg-1peak appeared in minhang district,299.761X10-8/m3kg-1, averages48.624X10-8/m3kg-1;Frequency magnetic susceptibility peak appeared in minhang pujiang farmland is5.877, the lowest in minhang district industrial zone of0.103.2, Space structure analysis, the results showed that sample with xuhui district soil in soil with frequency magnetic susceptibility index model, comply with spherical model, minhang district, the district to comply with the gaussian model, the whole sample area obey exponential model.Low frequency magnetic susceptibility and frequency magnetic susceptibility variation coefficient were80.426%and55.230%respectively, the frequency of magnetic susceptibility has strong variation, frequency magnetic susceptibility variation of medium.3, The different functional areas soil magnetism characteristic statistics show that low frequency magnetic susceptibility minimum appeared in xinzhuang park is14.501×10-8/m3kg-1, peak appeared in the industrial zone,315.610×10-8/m3kg-1averages48.624X10-8/m3kg-1;Different functional areas of low frequency magnetic susceptibility average order from large to small is traffic green (72.934×10-8/m3.kg-1), industrial zone (67.512×10-8/m3.kg-1), residential area (48.619×10-8/m3kg-1), pujiang farmland area (39.240×10-8/m3.kg-1), xinzhuang park (30.375×10-8/m3kg-1).4, Industrial zone,86.2%sampling point of low frequency magnetic susceptibility of soil<2%, especially in the industrial factory building and industrial areas on both sides of the road surface layer soil, show how for MD industrial zone of magnetic particles in the soil, but seldom from the SP.Industrial zone soil magnetic particles mainly comes from human activities, rather than soil.Traffic green land, farmland and industrial zone across the pujiang near the road side is low frequency magnetic susceptibility in the area of the xinzhuang parks and residential gateway, is obviously low.5, Function scales, the traffic green space, industrial zone, pujiang farmland, residential areas and xinzhuang park sample of magnetic susceptibility is greater than100×10-8/m3.kg-1sample points which are respectively26.67%,16.92%,4.55%,3.33%and4.55%;Minhang district district scale, magnetic susceptibility is greater than100×10-8/m3kg-1sample points which is8.51%;Sample with which8.46%.Frequency magnetic susceptibility, green transportation, xinzhuang parks, residential areas, and pujiang frequency magnetic susceptibility is less than3%of farmland sample points respectively account for93.33%of the total number of the sample piece of sample,86.84%,76.67%and72.73%, green traffic and industrial polluted soil is higher.6, Multi-scale time study, according to the characteristics of soil district scale scale, and each function of soil magnetic susceptibility nugget coefficient are less than 25%, with a strong spatial correlation, mainly structural variation;Belt scale coefficient of soil magnetic susceptibility piece of gold is100%, the space correlation is weak, give priority to with random variation.Function scales, the traffic greenbelt, xinzhuang park, residential areas and pujiang farmland soil magnetic susceptibility semivariance function model to comply with the spherical model, industrial zone soil magnetic susceptibility to comply with the gaussian model.District scale to comply with the spherical model, sample soil magnetic susceptibility to comply with the linear model with scale, form for pure gold, and showed that the sample belt scales, each sample point of soil magnetic susceptibility showed a greater independence and randomness.7, Belt scales, soil heavy metal Cr, Mn and Fe variation coefficient was0.142,0.178and0.142, respectively, belong to the weak intensity variation;Cu, Pb, and Zn variation coefficient was0.384,0.569and0.384, respectively, belong to moderate intensity variation.Minhang district district scale, soil heavy metal Cr, Mn and Fe variation coefficient is0.15,0.16and0.14respectively, belongs to the weak intensity variation;Cu, Pb, and Zn variation coefficient was0.33,0.62and0.33, respectively, belong to moderate intensity variation.Cu and Pb in the soil, Zn by interference is more significant, spatial differentiation is bigger, may be due to transportation, industrial and commercial the intense human activity such as urban construction land.8, Sample belt soil magnetic susceptibility and Cu, Cr, Mn, Pb, Zn, Fe correlation coefficient were0.250,0.207,0.039,0.393,0.416,0.056, and the correlation coefficient size order for Zn>Pb>Cu>Cr>Mn> Fe.Under the different functional areas, traffic greenbelt, xinzhuang park, residential and industrial area of soil Cu, Cr, Pb, Zn and other heavy metal with magnetic susceptibility has significant positive correlation.Frequency magnetic susceptibility and no obvious correlation between soil heavy metal content.Urban soil Cu, Zn and Pb content increased, the soil magnetic susceptibility also will increase, therefore, urban soil magnetic susceptibility size of Cu in the soil, Zn, Pb and other heavy metals pollution condition.9, City size and magnetism of soil characteristics, soil silt samples with the average percentage is79.995%, soil particle size powders minhang district average percentage is79.885%, belt and minhang district silt soil dominant, silt variation coefficient is the smallest. Sample with soil magnetic susceptibility and sand group was significantly positively related to particle content, contents of grains and powders has significant negative correlation.Industrial zone and pujiang farmland soil magnetic susceptibility and soil sand content was significantly positive correlation, the correlation coefficient was0.493and0.493, respectively, traffic and xinzhuang park green space, neighborhood no obvious correlation between magnetic susceptibility and sand content in the soil,Traffic green space, industrial zone, and pujiang farmland soil magnetic susceptibility and soil silt content has significant negative correlation, the correlation coefficient is0.276,0.245and0.245respectively, residential areas and xinzhuang park soil magnetic susceptibility and silt content correlation is not obvious.Pujiang farmland soil magnetic susceptibility χlf and soil texture clay content has significant negative correlation, the correlation coefficient is0.514, other functional areas and no obvious correlation between soil clay content.10, Urban soil organic matter and the characteristics of the magnetism of soil organic carbon average of11.35g/kg,0.66variation coefficient of organic carbon, belongs to the moderate intensity variation.Sample with average total nitrogen is1.4g/kg, total nitrogen content in the range of0.6-3.57g/kg, the variation coefficient is0.33, belongs to the moderate intensity variation.Sample with soil organic carbon content and soil total nitrogen content of the correlation coefficient is0.443, correlation is obvious.Sample with soil organic carbon content and soil magnetic susceptibility was significantly positively related, organic carbon and magnetic susceptibility correlation coefficient is0.402. |
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