长江源区主要河流表层沉积物及沿岸土壤重金属分布特征及来源

采用电感耦合等离子体质谱仪和原子荧光分光光度计测定了长江源区主要河流沉积物及周边土壤中14种重金属的含量,并采用富集因子法评价了长江源区主要河流沉积物及土壤中重金属富集程度,同时分析了河流沉积物及沿岸土壤中重金属分布特征及来源。研究结果表明:长江源区主要河流表层沉积物中,除Ni、Pb、Cd、Hg四种重金属外,其他元素含量均低于中国沉积物的平均含量;沉积物中Hg、Ni和Cd存在一定富集;与长江源区其他河流沉积物中重金属相比,沱沱河Cd含量相对较高,楚玛尔河重金属含量均相对较低,而通天河Hg和Fe含量相对较高;沉积物中重金属主要受自然因素影响。土壤中Ni、Pb、Cd、Ti略高于青海省土壤背景值,但重金属富集程度均较低;与长江源区其他河流沿岸土壤中重金属相比,当曲Cr、Ni、Cu含量相对较高,沱沱河Pb、Cd、Sb和Tl含量相对较高,而通天河V含量相对较高;重金属主要受自然因素影响,但部分重金属可能受交通因素影响。研究成果可为长江源区生态环境保护提供基础支撑。

Distribution Characteristics and Sources of Heavy Metals in Surface Sediments and Bank Soils of Major Rivers in Source Region of Yangtze River

The concentrations of 14 heavy metals in sediments and surrounding soils of major rivers in the source region of the Yangtze River were detected by using inductively coupled plasma mass spectrometry and atomic fluorescence spectrophotometer. The accumulation of heavy metals was evaluated by enrichment factor method, and the distribution characteristics and sources of heavy metals were also analyzed. Results unraveled that except for Ni, Pb, Cd, and Hg, all other heavy metals in river sediments were lower than the background values of sediments in China; however, Hg, Ni, and Cd were enriched in sediments. Compared with other rivers in the source region, Tuotuo River suffered from a relatively high concentration of Cd, Tongtian River was subjected to high concentrations of Hg and Fe, while Chumar River boasted a low concentration of all heavy metals. The heavy metals in sediments were mainly affected by natural factors. In terms of bank soils, the concentrations of Ni, Pb, Cd, and Ti were slightly higher than the background values of soils in Qinghai Province, yet with light enrichment.Compared with the soils along other rivers in the source region, the bank soil along Dangqu River had high concentrations of Cr, Ni, and Cu, and Tuotuo River Pb, Cd, Sb, and Tl, whereas Tongtian River saw a high concentration of V. The heavy metals in bank soils along rivers were mainly affected by natural factors, and also some affected by traffic factors. The research achievements offer fundamental support for the eco-environmental protection in the source region of the Yangtze River.