Study On Heavy Metal Pollution In Sediment Of River In Typical Industrial Area,Agricultural Area,Living Area Of Tiaoxi River

River sediments are not only the carrier of heavy metal pollutants and potential source of secondary pollutants in water,but also indicator of heavy metal pollution of water environment. Research on heavy metal pollution in river sediments has vital significance for heavy metal pollution control.In this paper, the surface and five core sediment samples in three typical areas were taken as the object of the research. Base on analyzing the physic-chemical properties, heavy metal contents and morphological characteristics,the pollution degree of soils were evaluated in the three typical areas of Tiaoxi River.Environmental 137Cs and 210Pb dating techniques were applied to determine depositionrates and era of heavy metal pollution.The conclusions were as follows:(1) Content of heavy mental were studyeded in surface sediments of each typical areas in Tiaoxi River;Base on geo-accumulation index results, The sediment of Three typical areas was light pollution, Cu,As and Cd was polluted in agricultural area of Xitiaoxi River.Cu,As and Cd were polluted.Based on the potential ecological risk assessment results,the sediment was at medium potential ecological risk level in industrial area of Dongtiaoxi River and light potential ecological risk in other areas.Cd was polluted in industrial area of Dongtiaoxi River,agricultural area of Xi tiaoxi River and living area of Tiaoxi River.(2)Identified pollution characteristics of Heavy metal in core sediments in three tyical areas of Tiaoxi River. The degree of heavy metal pollution of core sediment in Dongtiaoxi River was greater than Xitiaoxi River, the degree of heavy metal pollution of core sediments in industrial area was greater than agricultural area and living area and was severe pollution.Base on enrich factor assessment results, As Cu, As, Cd, Pb had certain pollution or enrichment in core sediment of Tiaoxi River.(3) Combining with the dating results and sediment deposition of heavy metals enrichment factor,this paper expounds heavy metals accumulation process in the sediments of each typical area.Since 1940s,Cu,Cd,As and Pb pollution in living area of Tiaoxi River began to aggravate.Since mid-1990s, Pb and Cu pollution began to aggravate. Cd has been severe pollution since 2007 in Xitiaoxi River.Since mid-1970s, the content of heavy metals in sediments from agricultural area of Dongtiaoxi River agricultural area with interannual variability remained stable. Cd,Cu and As all have been polluted.Since the late 1970s, Pb in sediments from industrial area of Dongtiaoxi River were in the moderate pollution.Cu,Cd,As and Hg were in the severe pollution. In the recent years, As pollution began increasingly serious.