渤海莱州湾沉积物REE与重金属污染特征及物源判别

基于莱州湾32个典型站位的表层沉积物样品，系统分析了稀土元素(REE)组成和分布特征以及重金属污染程度和污染来源；探讨了影响重金属和稀土元素分布的环境因素，并从重金属潜在源区、化学蚀变指数(CIA)和REE特征3个角度分析了莱州湾表层沉积物来源。研究表明，稀土元素总量自莱州湾东南部向北部递增，部分稀土元素（Eu、Gd和Tb）含量主要与细粒级的黏土矿物和有机碳含量相关，受化学风化的影响很小。研究区部分站位受到了Cd和Hg的污染，且主要是人类活动富集的；Cu、Pb、Zn可能源于地壳自然风化产物，其中Cu和Zn还与人类活动密切相关；Cr则受自然风化和人类活动的双重影响而富集；大部分重金属含量的累积还受湾内水动力的影响。沉积物源的判别结果显示，研究区CIA平均值为50.83，接近黄河沉积物的CIA值（50.9～59.7），低于中国黄土；研究区稀土元素配分模式和特征参数也与黄河十分接近，表明黄河是莱州湾表层沉积物的重要来源；广利河与潍河-弥河三角洲仅对南部和西南部海域沉积物有贡献，而黄土和山东省土壤对莱州湾沉积物的贡献量相对更少。

CHARACTERISTICS OF REE AND HEAVY METALS IN THE SURFICIAL SEDIMENTS OF LAIZHOU BAY,BOHAI SEA AND THEIR IMPLICATIONS FOR PROVENANCE

With the surface sediment samples collected from the 32 stations of Laizhou Bay, some critical environment problems, such as the composition and distribution patterns of rare earth elements (REE) and heavy metals, heavy metal pollution degree and the sources of pollutants are studied in this paper. Upon the basis, we made discussion on such environmental factors as the distribution of heavy metals and rare earth elements by means of heavy metal provenance, chemical alteration index (CIA) and REE characteristics. The results show that the total amount of rare earth elements increases from southeast to north in the bay, and the contents of some rare earth elements, such as Eu, Gd and Tb, are obviously related to fine grained clay minerals and organic carbon, and little affected by chemical weathering. Some stations in the study area are polluted by Cd and Hg obviously enriched by human activities; Cu, Pb and Zn might be the products of natural weathering of the earth crust; and Cu and Zn are also closely related to human activities; while Cr is influenced by both natural weathering and human activities; the accumulation of most heavy metals is affected by the hydrodynamic forces of the bay. Provenance discrimination results suggest that the average value of CIA in the study area is 50.83, close to the value of the Yellow River sediments (50.9～59.7), but lower than the value of the Chinese loess; the REE distribution pattern and characteristic parameters of the study area are also very close to the Yellow River, which indicates that the Yellow River is the most important source of surface sediments of Laizhou Bay; The Guangli River and Weihe-Mihe delta only contribute some sediments in the south and southwest, while the contribution of the Chinese Loess and the local soil in Shandong Province is relatively little.