关键词: 西洞庭湖, 扩张, 影响因子, 时空特征, 杨树人工林

Abstract: Aiming at the distribution characteristics of heavy metals in surface sediments of Qinghai Lake, 99 surface (0-20 cm) sediment samples were collected from 11 plots to measure the heavy metals (Zn, Cu, Pb, Ni, Cr, and Fe) contents. Geo-accumulation index and potential ecological risk index were adopted to evaluate the enrichment status of these heavy metals, and correlation analysis and factor analysis were conducted to approach the sources of these heavy metals. At tourist sites (dock 151 and Jiangxigou dock), surface sediments were slightly polluted by Zn and Cu; in Buha River, surface sediments were slightly polluted by Cr; while in the other plots, no pollution was observed. All the plots had a slight potential ecological risk. There existed significant positive correlations between the Cr, Fe, and TOC in the sediments. The Cr and Fe played significant roles in factor one (endogenous factor), and were mainly from sedimentary parent materials. The river water into the Lake also played an important role in Cr input. Both Pb and Zn had weak correlations with the other heavy metals, which represented the transferring and transformation patterns of factor two (agricultural activity) and factor three (tourist and traffic emission factors). The Pb and Zn were mainly affected by human activities. The Cu accumulation in surface sediments was related with endogenous, agricultural, and tourism emission factors. The Ni distribution was mainly affected by endogenous factors and tourist and traffic emission factors. Our results suggested that the heavy metals pollution and its potential ecological risk of surface sediments in Qinghai Lake were slight. In addition to endogenous factor, the agricultural activities around the Lake and the tourist and traffic emissions contributed to the pollution sources of the heavy metals.

Key words: West Dongting Lake, expansion, influential factors., poplar plantation, spatio-temporal characteristics