[Characteristics of heavy metal pollution in the sediments from Shahe Reservoir, the upper reach of the North Canal River].

Shahe Reservoir, in the upper reach of the North Canal River, was selected for researching on sediments heavy metals pollotion. History of the sediments was build and six heavy metals (Cr, Cu, Mn, Ni, Pb, Zn) were analyzed for distribution characteristics, the resoures of heavy metals were also studied by sediments enrichment factor and the relationship between heavy metal contents and socio-economic development in this region. The results showed that the 30 cm depth of the sediments represented the year of 1960, the time when Shahe Dam was built. The average contents of Pb and Mn from Shahe Reservoir central sediments were 30.6 mg x kg(-1) and 735.1 mg x kg(-1). While Cr, Cu, Ni and Zn had a centainy accumulation and their contents were all over 2 times higher respectively comparing to the background values of Beijing soil. From 1960 to mid-1980s, the contents of Cr, Cu, Ni and Zn had a sligtly change and their average contens were 51.2 mg x kg(-1), 36.0 mg x kg(-1), 31.5 mg x kg(-1) and 121.6 mg x kg(-1). However, during the period of next 20 years, the contents of these four heavy metals were elevated and their average contents were 1.4, 2.1, 2.8 and 4.3 times comparing to the foremost 20 years, which indicated that the enrichment of heavy metals was obvious during that time. While for spatial distribution, the sediments from the center of the reservoir had higher contents of heavy metals than the sediments from the estuary of the reservoir. In terms of the sources of heavy metals in the sediments from Shahe Reservoir, it was recognized that Cr, Cu, Ni and Zn were influenced by anthropogenic activities while Mn and Pb were mainly originated from natural soureces.