嵩山景区旅游活动对土壤组成性质和重金属污染的影响

Impacts of tourist activities on components,properties and heavy metal pollution of soils in the Songshan scenic area

沿嵩山景区登山路线,在嵩阳书院(455m)、老母(715m)、石船(930m)和天爷庙(1490m)采集混合土壤样品,在离景点200m以外的受旅游活动影响微弱的地方采集对照土壤样品。根据我国土壤常规分析方法或国家标准分析方法开展土壤组成、性质和重金属(Cu、Zn、Pb、Ni、Cd和Cr)含量分析。与对照样相比,景点土壤具有以下特征:①黏粒含量高,质地偏细,相对紧实、干燥,根系分布少,颜色浅。②CEC小,盐基饱和度大,pH高。③有机质含量下降,速效养分减少,肥力衰退。④黏粒部分CaO含量高,SiO2含量相对下降,Saf减小,出现"假淋溶风化现象"。⑤土壤重金属含量高于对照样,大部分超过我国棕壤和褐土背景值。土壤Cu和Ni没有发生污染,其它重金属污染程度的次序为:Zn>Pb>Cd>Cr;不同景点重金属污染程度的次序为:嵩阳书院>老母洞>天爷庙>石船。

The mixed soil samples were collected at the main tourist sites with different altitude such as Songyang College,Laomu Cave,Stone Ship and Tianye Temple along the mountain-climbing path of the Songshan scenic area,Henan province.At the same time,the control soil samples were collected at the sites 200 m away from the scenic sites,where the impacts of tourist activities on soils are very weak.Total chemical composition of soil clay,physicochemical properties,and the concentration of heavy metals（Cu,Zn,Pb,Ni,Cd and Cr）in soils were measured for the prepared soil samples,using the common methods offered by the Institute of Soil Science,CAS,Nanjing,and the standard methods of China.The results show that tourist activities have a substantial impact on the soils in the Songshan scenic area.Compared with the control soil samples,scenic soil samples have following characteristics：（1）Soil clay contents in the scenic samples are higher,soil textures are heavier,soils are relative solider and more dry,root densities in soil surface layer are smaller,soil colors are lighter than that of in the control samples.（2）Cation exchange capacities（CEC）in the scenic samples are smaller,base saturation percentages（BSP）and pH values are higher than that of in the control samples.（3）Soil organic matter（SOM）and available nutrients（K,N,P）in the scenic samples are less than that of in the control samples.（4）The concentrations of CaO in clay part of the scenic samples are much higher,the SiO2 and silica-sesquioxide ratios（Saf）are smaller than that of in the control samples.The ＂pseudo weathering eluviations＂ occur in the scenic samples,not in the control samples.（5）The concentrations of most heavy metals in the scenic samples are higher than that of the background values of the brown soils and the cinnamom soils in China,and that of in the control samples.Cu and Ni in the scenic samples were not polluted based on the first reference values for soil pollution specified in the GB15618-1995,but the others were polluted from medium to heavy degrees.The pollution order of the heavy metals in the scenic samples is Zn〉Pb〉Cd〉Cr,and the pollution order of the scenic spots studied is Songyang Collage〉Laomu Cave〉Tianye Temple〉Stone Ship.