| With the industrialization and urbanization,the soil pollution is becoming more and more serious.The soil magnetic technologies is favorable used in the soil pollution monitoring in recent years because of its simplification,nondestructive to samples and low expense.By measuring magnetic parameters of soil sample,connecting parameters to soil heavy metals then studying the response of soil magnetic property to soil heavy metal pollution,then knowing the influence of human activities on soil environment,hereof,to predict the long-term change trend of soil environment.In this paper,topsoil samples were taken from Fuzhou city,the magnetic susceptibility parameters such as the low frequency magnetic susceptibility?Xlf?,the high frequency magnetic susceptibility?xhf?and the frequency magnetic susceptibility?Xfd?,and the concentrations of the heavy metals of Cu,Zn and Pb,were measured in the laboratory.By spatial analysis technology,the spatial pattern of the soil magnetic parameters and the heavy metals were demonstrated.The relationship analysis between the soil magnetic parameters and the heavy metals revealed the threshold series for assessing soil heavy metals by using of the low magnetic susceptibility.The important results of the analysis are listed as the following:?1?The characteristics of soil magnetization in Fuzhou:the variation ranges of Xlf,Xhf and Xfd were 3.39-1014.57×10-8 m3/kg,3.21?1006.29×10-8 m3/kg,0.02?35.28%.The average values of Xlf,Xhf and Xfd were 138.86×10-8m3/kg,136.13×10-8M3/kg,3.64%.The spatial structure analysis showed that the magnetic susceptibility accords with the exponential model,showing strong spatial autocorrelation and random variation.The high values of soil Xlf and Xhf were mainly in the southwest and northeast,the low values were both concentrated in the northwest and southeast,but the distribution of Xfd was opposite.One-way ANOVA showed that Xlf of farmland,forest land,grass land and construction land were different.There was significant difference between the Xlf of forest land soil and that of construction land.The result of Xhf variance analysis was consistent with that of Xlf,and there was no significant difference among the Xfd of five land types.?2?Heavy metal content of soil and spatial distribution:contents of Cu,Zn,Pb in soil were 6.09?94.6 mg/kg,2.2?383.13 mg/kg,13.95?121.7 mg/kg.The average values were 23.85 mg/kg,96.97 mg/kg,42.14 mg/kg.The average contents of Cu,Zn,Pb were 1.1 times,1.2 times and 1.2 times respectively as much content as background value of soil in Fujian Province.The average values of the three heavy metals were not higher than that of the second grade national standard of soil environmental quality.Spatial structure analysis indicated that Cu and Pb fitted linear model and Zn fitted Gaussian model.There were weak spatial correlation about Cu and Pb,Zn had strong spatial correlation.One-way ANOVA showed that there was significant difference among Cu content of farmland,forest land,grass land,horticultural land,and construction land.There was also significant difference among Pb content between farmland,forestland,grass land and construction land.The results of pollution load index calculation showed that the order of single factor pollution index average values of heavy metals in total soil samples were:Pb?1.21?.>Zn?1.17?>Cu?1.1?,mildly polluted.PLI of 0.74 was unpolluted.?3?Magnetic diagnostic value sequence of heavy metal pollution:when Xlf less than 33.42×10-8 m3/kg,soil is completely clean.When Xlf between 33.42?57.39×10-8 m3/kg,accumulation of Pb.When Xlf between 57.39?62.40×10-8m3/kg,accumulation of Pb and soil mildly polluted.When Xlf between 62.40?90.51×10-8m3/kg,accumulation of Pb,Zn and soil mildly polluted.When Xlf between 90.51-492.17×10-8 m3/kg,the soil is mild polluted.When Xlf between492.17?926.96×<10-8 m3/kg,the soil is moderately polluted.When Xlf more than 926.96×10-8m3/kg,the soil is highly polluted.. |
PDF Full Text Request