Evaluation And Source Identification Of Heavy Metal Pollution In Urban Rivers

This study investigated the occurrence and morphological characteristics of heavy metals?Pb,Cr,Zn,Cu,As,Fe and Ni?in Huangpu River,Shanghai.Through the use of a variety of pollution assessment means to analyze their pollution degree and use of a variety of source analysis means to analyze the pollution sources of heavy metals such as As,Ni,Cu,Pb,Zn,Cr,Sr,Cd,Mn,Fe and P?non-metal?to better explain the influences of population,traffic,industrial distribution and urbanization process on the huangpu river.The main conclusions of the research were summarized as follow:?1?On the whole,heavy metal pollution such as Pb,Cr,Zn,Cu,As,Fe and Ni were mainly concentrated in the middle and downstream areas in Huanpu River and their pollution more serious in spring.The evaluation results of single factor and nemero composite index show that Fe was seriously polluted with grade V in the four seasons,while Pb was seriously polluted with heavy metals in the spring.The water pollution assessment results of heavy metals such As,Zn,Cu,Cr were all grade I.This means they did not produce any pollution to the water environment.?2?The average seasonal concentrations of As,Pb,Zn,Cu,Cr and Ni in the sediments were as follows:in spring,Zn>Cr>Ni>Cu>Pb>As;in summer,Zn>Ni>Cr>Cu>Pb>As;in autumn and winter,Zn>Cr>Pb>Cu>Ni>As.Moreover,the sampling points with high proportion of oxidizable state,reducible state,acid extractable state and residual state are mainly concentrated in the lower reaches of the huangpu river basin according to season and spatiotemporal factor change obviously.Among them,the F3 states of Zn,Pb and Cr are strongly correlated with TOC in spring.Cu has the greatest correlation in winter.The correlation of Ni in summer,autumn and winter is larger.?3?According to the analysis results of various pollution assessment methods,as for the total amount of heavy metals,Pb pollution in the Huangpu River is the most serious,followed by Cu,Cr,As,Zn and Ni.Their levels of pollution vary according to time and space change;As for the form of heavy metals,the pollution of Zn and Pb is moderate pollution which has a high risk of ecological pollution.However,Ni,Cu and Cr are all in the non-pollution to the moderate pollution level.Their pollution situation is relatively weak.The potential ecological risk degree of each element in autumn and winter is greater than theirs in spring and summer.?4?The source analysis results of multivariate statistical analysis indicated that Zn,Sr,Cu,Cr and Pb in the sediments of Huangpu River were affected by both industrial and traffic sources.Fe,P and Ni were from agricultural and natural sources.Cd,Mn and As were mostly related to industrial sources and natural causes.Fe,P and Ni were from agricultural and natural sources.Cd,Mn and As were mostly related to industrial sources and natural causes.The analysis results of?⁶⁵Cu and?⁶⁶Zn isotope source further indicated that the Cu in the water samples was mainly from traffic aerosol?large amount?,construction and industrial coal emission.The Zn in sediments was mainly from the sources of traffic aerosol and tyre wear.The Cu in sediments was mainly from the sources of shipbuilding,shipping and transportation,industrial smelting of coal and metal.Importantly,the combined tracing results of?⁶⁵Cu and?⁶⁶Zn indicated that the pollution was the result of the interaction between human and natural sources.