Analysis Of Dust Retention And Stagnation Of Heavy Metals Of Leaves In Common Tree Species In Different Regions

In order to evaluate the effect of leaves of common tree species to retain dust and absorb heavy metals,this study investigated the dust collection data of seventeen common greening tree species in fourty-three cities and absorption of heavy metals of eight tree species in twenty-four cities through a large amount of literature research in the normal weather,these data were compared,analyzed and discussed the differences in dust retention and heavy metal content in different tree species leaves under multiple urban environments and their influencing factors.The results show:(1)The dust retention effect of the leaves of seventeen tree species in descending order:Buxus sinica>Platycladus orientalis> Sabina chinensis> Buxus megistophylla> Cedrus deodara> Prunus cerasifera> Lagerstroemia indica> Platanus hispanica> Magnolia grandiflora> Osmanthus fragrans> Ligustrum lucidum> Pinus tabulaeformis> Cinnamomum camphora> Sophora japonica> Koelreuteria paniculata>Ginkgo biloba> Salix babylonica,but Ligustrum lucidum has the greatest dust retention potential.(2)The tree species with the largest heavy metals stagnation for Pb,Cd,Cu,and Zn are Ginkgo biloba,Cinnamomum camphora,Sophora japonica,and Cinnamomum camphora,and the tree species with the largest stagnation potential for Pb,Cd,Cu,and Zn are Sophora japonica,Platanus hispanica,Sophora japonica,Sophora japonica.The stagnation of Pb and Cd in the leaves of Cinnamomum camphora was less affected by regional environmental changes,and it was more applicable in southern China than other seven tree species.The stagnation of Cu and Zn by Ligustrum lucidum leaves was affected by regional environment changes and was more universal than the other seven tree species.(3)The dust retention effect of leaves of shrub species is greater than that of arbor species.The dust retention effect of coniferous species is greater than that of broad-leaved species.(4)The dust retention of leaves of most tree species is greater in southern cities than that of northern cities.In general,the stagnation of Cu of leaves of the four tree species of Ligustrum lucidum,Platanus hispanica,Ginkgo biloba,and Koelreuteria paniculata are lower in southern cities than in northern cities,and there is no significant difference in the stagnation amounts of Pb,Cd,and Zn.In terms of seasonal dust retention,the leaves of the studied tree species have their own characteristics of dust retention in summer and autumn,and there is no obvious tendency for seasonal dust retention.The stagnation of Pb by leaves of the five tree species of Ligustrum lucidum,Platanus hispanica,Magnolia grandiflora,Cinnamomum camphora and Sabina chinensis are lower in summer than in autumn,and there is no significant difference in the stagnation amounts of Cd,Cu,and Zn.(5)Except for Platanus hispanica,the average dust retention of Ligustrum lucidum,Magnolia grandiflora,Cinnamomum camphora and Koelreuteria paniculata are lower in provincial capital cities than in prefecture-level cities.All in all,the stagnation of Pb and Cu by leaves of the five tree species of Ligustrum lucidum,Platanus hispanica,Magnolia grandiflora,Cinnamomum camphora,and Koelreuteria paniculata are lower in provincial capital cities than in prefecture-level cities,and there is no obvious difference in the stagnation amounts of Cd and Zn.The influence of a single urban development parameter on the amount of dust retention and heavy metal stagnation of tree leaves is limited,a variety of factors work together to determine the dust retention effect and heavy metals stagnation effect of tree leaves.In the future,the dust retention of leaves of the whole tree species and the differences in heavy metal stagnation of different parts of tree species(roots,trunks,branches,etc.)can be explored.providing more accurate scientific basis,when city departments selecting green tree species.