Characteristics Of Heavy Metal Pollution In Soils Of Main Function Areas Of Xiamen And Pb And Sr Isotopic Tracers

In recent years, heavy metal contamination in soil has increasedsignificantly and endangered human health. In this paper, soil samples,including9topsoils and3vertical profiles, were collected from Xiamen city.In order to know about the distribution of heavy metals in soil, concentrationsand the distribution characteristics of chemical speciation of heavy metals inthe soil samples have been investigated. Pb and Sr isotopes and multivariatestatistical analysis were used to trace the sources of heavy metals in soil. Theresults showed:The concentration of most heavy metals in the topsoil of traffic area decreasedalong with the increase of distance. The minimum values were found at31mor127m from the highway. Most of heavy metals in the soil profiles presenteddownward trend.The chemical speciation of heavy metals in the samples was analyzed by BCRsequential extraction method. The results showed that Cr and Cu in topsoil oftraffic area mainly existed in oxidizable fractions, Zn mainly existed in acidextractable fractions, and Ni, Pb, Fe, Mn and Sr mainly existed in residualfractions. Comparison of the concentration of each species of elements (Cu,Zn, Pb, Fe and Mn) were conducted between dryland soil from Xiamen andpaddy soil from Quanzhou. The results showed that Pb, Fe and Mn in paddy soilwere more mobile and bioavailable than dryland soil.The Nemerow integrated pollution index, geoaccumulation index andratio of secondary phase to primary phase (RSP) were used to assess theenvironment risk of heavy metal pollution in soil. The result showed that soilwas polluted seriously by Cd except of the soil profile in traffic area. The resultalso showed that the pollution of Cu in traffic area was severe and thepollution of Mn in agricultural area was slight or severe.The analysis of Pb pollution sources and the corresponding anthropogenic Pb contributions in soil by Pb isotopic tracing showed that, thecontribution rates of anthropogenic Pb source in the topsoil and the soil profilesfrom the intense traffic area in Xiamen were43.22%and39.81%, respectively,while the soil profiles from the intense traffic area and agricultural area inQuanzhou were63.51%and80.17%, respectively.The sources of heavy metals in the soil were investigated by using Pband Sr isotopes and multivariate statistical analysis. The result showed thatCu, Zn, Cd and Pb in the intense traffic area were mainly from traffic pollution,Mn in the agricultural area was mainly from manure, Cu and Zn were mainlyfrom pesticides, and Cd was mainly from phosphorus fertilizer.