Pollution Characteristics And Source Analysis Of Heavy-metal Elements In Xingqiao River

Tongling is one of the most important copper industry city in China. Themining activities got huge benefit, however, caused the serious environmentalpollution. The heavy metals can enrich in the organism and human’s body easily,and harm the human’s health indirectly or directly. If the heavy metals enter to theriver, they can stay in the sediments of river and produce the secondary pollutions.So it’s important for controlation and elimination of environmental pollution toknow the pollution characteristics of sediments and the source apportionment ofheavy metals. In this paper, we studied the sediments and water of the XinqiaoRiver. Based on the measured concentration of heavy metals of sediments and thespeciation characteristics of heavy metals, we evaluated the pollution degree ofthe Xinqiao River. The XRD and SEM-EDS technology, principal componentanalysis(PCA), lead and sulfur isotopes were used to find out the sources of heavymetals in the sediments. The conclusions are below:The mining activities lead to the pollution of some part of the river. The majorcontaminated metal elements include Pb and Cd. The concentrations of Cu, Znand As of some samples exceed the environmental quality standard for surfacewater. The concentration of Hg is lower than the limit of detection.The concentrations of Cu, Zn, Pb, Cd, As and other heavy metal elements insediments are high and influenced by the mining activities obviously, but notcontrolled by the distance increasing. The order of average concentrations of heavymetals is Zn>Cu>Pb>As>Cd>Hg.The Geo-accumulation Index shows that the sediments are polluted by miningactivities. The degrees of pollution of Cu and Cd are highest, that of As is higher,those of Pb and Zn are moderate, and the sediments are not polluted by Hg. ThePotential Ecological Risks Index shows that the order of potential ecological risksof heavy metals are Cd>As>Hg>Cu>Pb>Zn, and the Cd is the main pollution, itcontributs more than50%to the risk index.The speciations of heavy metals are varied. The active form of Cd is highest,so Cd has the highest ecological risk.As has little harm. The Fe-Mn oxides formsand organic forms of Pb, Cu and Zn are higher, and the ecological risks of these elements are controlled by the oxidation-reduction condition and pH.The XRD and SEM-EDS analyses show that the minerals of the no polluted orless polluted sediments include quartz and feldspar mainly which are therock-forming minerals, and some Berlinite and Sidorenkite which come formgranite and sedimentary. The minerals of the polluted sediments are complex,including goethite,goethite,despujolsite,hentschelite.The PCA analysis can discern the source of Pb, Zn and As. The results showthat the Pb came from the lead-zinc ores and Cu-Au-S ores,The Zn came from thelead-zinc ores and domestic wastewater,The As came from Cu-Au-S ore mainly.The lead and sulfur isotopes results indicate that the Pb and S are mainlycontrolled by the mining of Xinqiao mine. The binary mixing modeling show that85%of the sediment Pb in the middle and lower Xinqiao River came from the oresof Xinqiao mine.