简介：NinePlatanusacerifolia(Ait),Willd.treesgrowingintheNanjingChildrenTeacher'sSchool,Nanjing,China,wereselectedtodeterminethecontentsof13chemicalelementsbothinthe1994'sgrowthrings,C(Z,t),andinthesoilsneartheroots,C′(Z,t),ofthetrees,Theresultsshowedthattherelationshipbe-tweenC(Z,t)andC′(Z,t)followedthelogarithmiclinercorrelationmoedl.lgC′(Z,t),=a(Z)+b(Z)lgC(Z,t),Basedonthismodelthechrono-sequencesofchemicalelementcontentsinthesoilswerereproducedfromtthoseihthetreerings;i.e.,thedynamicvariationsinthechemicalelementcontentsofthesoilsatthesitesweretrced.Inthisstudythechrono-sequencesofthechemicalelementsincludingCd,Pb,Mn,CoandZninthesoilsneartherootsofaPlatanusacerifoliatreefrom1957to1994wereestablished,andthebackgroundvaluesofCd,Pb,Mn,CoandZninthesoilwerecalcuatedbytakingthelowestvaluesofthechrono-sequencesoftheelementconentsasupperlimitsofthebackgroundvalues.