论文部分内容阅读
During last years big attention is given to studying of a soil cover and application of a magnetic susceptibility (MS) for the defmition of its technogenic changes.Magnetic properties of technogenic and natural soil were investigated by Babanin V.,etc.,1995,Magiera T.,et al.,2002,Caggiano R,DEmilio M.,2003,Kapi(c)ka A.,Petrovsky E.et al.,2005,H.Lecoanet,F.Leveque et al.,2006,etc.Method of detailed studying of MS distribution of Moscow soil cover was developed.Field,laboratory,cartographical and statistical methods were applied for this purpose.Thus,160 nodes (in each 1-5 plots) and 395 plots (on each 13 measurements) were characterized; about 8000 values of MS were obtained.The statistical processing data set obtained for the MS showed,that the distribution of (e) is described by lognormal distribution function.This distribution often describes the phenomena related to the return of technogenic products of manufacture in an environment.The main cause of increase of MS values are regular dust fallouts from permanent sources (factories,highways and railways,etc.) and casual,local (various technogenic and man-caused artifacts) which are manifested by abnormally high values of MS.Values of an average and a dispersion are usually used for an estimation of distribution of received data.It is offered to expand the group of statistical parameters of MS by use of minimal-(a)min and maximal-(a)max values for each unit.The (a)min values are indicative of the least changes in a soil sample at a specific surface point,Abnormally high (a)max values,a high variance σ(a)2,and low (a)av values obtained for a test plot of soil indicate the presence of technogenic artifacts in some of its points.The plots with abnormally high (a)max values,high (a)av values,and relatively low variance σ(a)2 are subjected to the most intense action of contaminating factors.Moderate (a)av values and a low variance σ(a)2 indicate predominantly aerosol contamination,and the variance or difference ((a)max--(a)min) characterizes the degree of heterogeneity of the plot.Magnetic measurements were also offered to use for an estimation of degree technogenic loading of areas of urban soil.For this purpose statistical regularity of lognormal distribution of MS-f((a)i) was used," specifically the presence of critical points-a maximum and excesses on the curve.The scale of 4 gradation was worked out depending on certain range of MS value:technogeniccally not loaded areas low-,medium-and strongly technogeniccally loaded soil areas which are defmed by value of (a)av from less 0,46 up to more 1,0 up to 10.10-3SI.We also proposed concept of contrast of soil areas according technogenic pollution.The degree of contrast allows indicating the degree of homogeneity of technogenic pollution.We develop 4 mark estimation of contrast according the difference of values (a)max and (a)min from low-contrast up to strong-contrast soil areas.On this basis,three sketch maps were drawn for distributions of MS ((a)min,(a)av и (a)max) in the surface horizon of Moscow soils.Also sketch maps of contrasting and loading of soil by teclmogenic deposits were drawn.As it is known,areas with increased MS (>1·10-3SI) in the territory of Moscow correspond to the areas of large metal-processing plants,heavy engineering industries,construction industries,and large railway junctions.But it is important,that also considerable areas (about 30% of the whole city) of local territories corresponding various old-contaminated territories have been revealed.The average values of the magnetic susceptibility for the areas of parks,forests,recreation zones,and residential quarters correspond to the reference values (> 1.10-3 SI) for soils of this zone.It is revealed,that in Moscow on a share oftechnogeniccally not loaded areas is about 40 %,and low-,medium-and strongly technogeniccally loaded-22 %,17 %,21%,accordingly.Non-contrast areas on the studied territory-12 %,and low-,medium-and strongly contrasted -15 %,16 % and 57 % accordingly.Thus,the offered method allows to estimate detail distribution of tectnogenic pollution of soils in the city.It is offered to use the minimal and maximal values besides average values and dispersions that allows to reveal local areas of pollution.