[Relationship Between Landscape Pattern and Spatial Variation of Heavy Metals in Aquatic Sediments in Headwaters Area of Yuqiao Reservoir]

Yuqiao Reservoir, an important adjusting reservoir in the project of diverting water from the Luanhe River to Tianjin City, is an important water resource for Tianjin City. Concentrations and spatial variation characteristics of Cd, As, Pb, Cu, Cr, and Zn from 33 sub watershed sampling sites of Yuqiao reservoir and the relationship to landscape pattern were discussed. The result showed that average concentrations of Cd, As, Cu, Cr in suspended particulate matter were higher than Chinese environmental quality standard Grade one for soils, and there were ecological risks for them because they could arrive at Yuqiao reservoir. The average concentrations of Cd, As, Pb, Cu, Cr, and Zn in surface sediments were 0.32 mg·kg^-1, 30.39 mg·kg^-1, 33.49 mg·kg^-1, 58.20 mg·kg^-1, 90.16 mg·kg^-1 and 94.80 mg·kg^-1 respectively. The average concentrations of Cd, As, Cu and the concentrations of Pb, Cr, Zn in partial samples exceeded Chinese environmental quality standard Grade one for soils. The average concentrations of Cd, Cr, Zn in surface sediments of three tributaries increased in the order of Linhe River >Shahe River >Lihe Rier, Cu decreased in the order of Linhe River < Shahe River < Lihe River, and As, Pb increased in the order of Shahe River >Linhe River >Lihe Ricer. Land use types in Yuqiao reservoir basin had some impact on the distribution of heavy metal concentrations in river surface sediments. Woodland and shrub grass land determined the natural distribution trend of heavy metals in surface sediments. Gardenland and industrial & mining land usage had impact on Cd, As, Pb, Cr distributions. Farmland and village & town land usage did not produce negative influence on heavy metal distribution.