金华市武义江沉积物磁性特征及其对重金属污染的指示意义

Magnetic characteristics of the sediments of Jinhua Wuyi River and their environmental implication

对浙江省金华市武义江边滩柱样沉积物进行了系统的环境磁学、地球化学、粒度和总有机碳分析,探讨河流沉积物磁性特征的影响因素及其环境意义.结果表明:1)武义江沉积物磁性特征为磁铁矿主导,沉积动力分选和沉积后的次生变化对磁性特征的垂向变化产生影响;2)武义江沉积物中各类重金属元素含量高于背景值水平,存在不同程度的人为因素的污染和富集;3)武义江沉积物磁性参数与重金属含量存在一定正相关关系,反映了磁性矿物与重金属具有相同的来源,或者磁性矿物对重金属的吸附作用,表明河流沉积物磁性特征可定性地指示重金属污染.

Environmental magnetism,geochemistry,grain size,and total organic carbon analyses were conducted on a short core from the Wuyi River in Jinhua,Zhejiang province. It was aimed to investigate the magnetic properties of the river sediments and its environmental implication significance. The results indicated that: 1) The magnetic properties of sediments were dominated by ferrimagnetic mineral magnetite. Particle size sorting and post-depositional alteration had impact on the vertical variations of magnetic properties. 2) Heavy metals showed different degrees of pollution and enrichment. 3) There were positive correlations between magnetic parameters and heavy metal content. It reflected that magnetic minerals and heavy metals might have the same origin,or the fine particles of magnetic minerals might adsorp heavy metals. It showed that magnetic properties of sediments could be used as a qualitative indication of heavy metal pollution in river sediments.