霍侯一级路两侧土壤磁化率空间分布及其对重金属污染指示意义

Spatial Distribution of Magnetic Susceptibility and Its Implication as Indicator of Heavy Metal Pollution in Roadside Soils along Huohou Road

以霍侯一级路表层土壤为对象,测定土样的磁化率、重金属(Pb、Cu、Zn)含量和理化指标,利用统计分析对重金属来源进行分析并对污染做出评价.结果表明:公路两侧土壤的低频和频率磁化率均值分别为77×10^(-8) m^3kg^(-1)和5.46%,土壤中超顺磁颗粒含量较少,磁化率的高值主要由人为活动产生的磁性颗粒沉积造成.随着到公路距离的增大,低频磁化率减小,而频率磁化率增大.Pb、Cu、Zn的含量分别为33.76-150.45mg/kg、18.41-67.86mg/kg和40.53-240.67mg/kg,都不同程度的超过山西土壤背景值.低频磁化率与pH、频率磁化率呈显著负相关,与砂粒含量正相关,而频率磁化率与粘粒含量呈负相关,有机质与磁化率表现弱相关,三种重金属之间相关性也很高.污染评价表明重金属的污染程度由强至弱依次为:Pb>Zn>Cu,土壤环境总体处于中度污染.另外,基于磁化率的土壤分级标准得出的土壤污染程度也符合积累指数计算得到的结果,但此法的适用范围还有待于进一步的研究.

In order to identify and evaluate the pollution of heavy metals caused by road trans- portation,the physio-chemical indicators, content and spatial distribution of heavy metals （Pb, Cu and Zn）,magnetic susceptibility level of the roadside soils along Huohou Road were investigated in this study. The results showed that, the average values of low frequency magnetic susceptibility and frequency magnetic susceptibility are 77 × 10^-8 m^3kg^-1 and 5. 46%, respectively, which indicated that the high value of magnetic susceptibility was caused by traffic since the contents of superpara- magnetic （SP） in soil samples are relatively low. The means of magnetic susceptibility were decrea- sing and the frequency magnetic susceptibility were increasing with the sample plots＇ distance to the road expanding. The contents of Pb, Cu, Zn in the soils were 33. 76- 150. 45mg/kg, 18. 41- 67.86mg/kg and 40.53-240.67mg/kg,respectively,which were all higher than the basic values of soil in Shanxi Province. The low frequency magnetic susceptibility was negative correlated with pH and frequency magnetic susceptibility. The correlation between magnetic susceptibility and O. M is very weak, basically did not exist on the soil genetic link. Moreover, the correlation between the three metals was significant. The pollution levels of the three metals were Pb〉Zn〉Cu. Generally, the soils in study area were under moderate pollution condition. The grading standard which based on the magnetic susceptibility was consistent with the results obtained by accumulation index calcu- lation. But this idea was proposed preliminarily and its scope of application needs further investigation.