Distribution Characteristics Of Heavy Metals And Microbial Biomass Carbon On Greenway Soils

Soil and plant samples were collected according to the land-use types along Huning expressway and No.209 provincial expressway,the effect of traffic to heavy metal pollution in soils and the protective function of greenway construction to heavy metal pollution.The results indicated:1.The heavy metal(Cu,Pb and Zn)contents in different soil layers along Hurting Expressway and No.209 provincial expressway were ruleless;the amount of soil microbial biomass carbon in 0～10cm soil layer was higher than that in 10～25cm soil layer.2.The relationships between heavy metal(Cu,Pb and Zn)contents and the increase of distance from soil sampling spots to road were not the simple negative correlations.The trends were:heavy metal contents increased with the distance to road at first,and then decreased with the distance,the peak values appeared from 10 m to 50 m of the distance to the road.3.Greenway constriction was positive in weakening heavy metal pollution in soils,which indicated in lowering the peak and mean values of heavy metal contents. However,the protective function of greenways was greatly affected by the structure, breadth.Soil microbial biomass carbon along Huning expressway and No.209 provincial expressway increased with distance increase from soil sampling spots to road.4.Different plant leaves have different ability in heavy metal enrichment.The enrichment coefficients to Cu,Pb of populus leaves were apparently larger than those of cinnamomun camphcra leaves;the opposite was true concerning to Zn, which showed that the enrichment ability to Cu,Pb of populus leaves and the enrichment ability to Zn of cinnamomun camphcra leaves were stronger, respectively.5.The heavy metal(Cd,Cu,Pb,Zn)contents of populus leaves along Huning expressway decreased with the distance increase from soil sampling spots to road, and the heavy metal(Cd,Cu,Pb,Zn)contents of cinnamomun camphcra leaves along the No.209 provincial expressway increased with the distance.The amount of heavy metals in crops along Huning expressway and No.209 provincial expressway decreased with distance increase from soil sampling spots to road.6.Heavy metal contents correlated negatively with soil microbial biomass carbon along Huning Expressway,while along No.209 provincial expressway,heavy metal contents correlated positively with soil microbial biomass carbon.Positive correlations were found between Pb and Cu,Zn and Cu,Zn and Pb along Huning Expressway,Pb and Cu along No.209 provincial expressway.Heavy metal contents in soil did not correlated positively with the metal contents in plants.