长白山自然保护区道路影响域土壤Zn和Pb分布及污染分析

分别在长白山自然保护区北坡的阔叶红松林、针叶林和岳桦林等3种森林中不同利用强度的6个路段,垂直于道路设置长50 m、宽10 m采样断面,在距路基4、12、20、28、40和48 m随机采集表层0~20 cm土壤,利用ICP-ES测定土壤样品中Zn和Pb的含量。研究不同森林类型、不同利用强度道路50 m路域范围土壤重金属含量、分布特征和污染状况。结果表明:随道路利用强度增强,在阔叶红松林和岳桦林带,路域50 m范围土壤Zn和Pb含量增加明显;在针叶林带,路域50 m范围土壤Pb含量增加明显;随道路利用强度增强,Pb在阔叶红松林带路域土壤中积累范围为12~28 m,在针叶林带路域中积累范围为20~40 m,在岳桦林带路域0~50 m范围积累都明显;与阔叶红松林带土壤相比,岳桦林带路域土壤Pb含量变化对道路产生的Pb污染更敏感;利用强度强的岳桦林带路域土壤Zn和Pb的污染分指数最大,分别为1.49和1.52,都为轻度污染。

Assessment of Contamination and Spatial Distribution of Zn and Pb in Roadside Soils of Changbai Mountain Nature Reserve

The concentration,distribution pattern and contamination of heavy metals in roadside forest soils within 50 m adjacent to main roads were studied in Changbai Mountain Nature Reserve.Soil samples were collected from six sites along six roads with different use intensity in different types of forests(broad-leaved Korean pine forest,coniferous forest and Betula ermanii forest).At each site,topsoil samples(0-20 cm) were taken at different distances from road edge within the transect(50×10 m) parallel and perpendicular to the roadway.Total concentrations of Zn and Pb were determined using the ICP-Emission Spectrometry.The results showed that: with the increase of utilizing intensity of roads,the concentration of Zn in soils at every soil sampling point was enhanced significantly within 50 m from roadside in broad-leaved Korean pine forest and Betula ermanii forest.Within 50 m from the roadways with high use intensity,the accumulations of Pb in soils in broad-leaved Korean pine forest and coniferous forest were significant from 12 m to 28 m,20 m to 40 m,respectively.However,in Betula ermanii forest,the concentrations of Pb in soils at all sampling points within 50 m from the road edge with high use intensity were higher than that with low use intensity.Compared to the soils in broad-leaved Korean pine forest,the roadside soils in Betula ermanii forest were sensitive to the pollution of Pb caused by road traffic.Among the six sites,the contamination index(P(i)) values for Zn and Pb in soils collected within 50 m of the road with high use intensity in Betula ermanii forest were the highest.And the area was classified as a slight pollution zone.