• 关键词：环境磁学  重金属污染  河流沉积物  粒度  富集因子  义乌江

• 基金项目：河口与海岸学国家重点实验室开放基金项目(No.SKLEC-KF201205);国家自然科学基金(No.41371206)

• 李文
• 浙江师范大学地理与环境科学学院, 金华 321004

• 胡忠行
• 浙江师范大学地理与环境科学学院, 金华 321004

• 吉茹
• 浙江师范大学地理与环境科学学院, 金华 321004

• Nguyen Thi Thu Hien
• 华东师范大学河口海岸学国家重点实验室, 上海 200062

• 刘晋嫣
• 华东师范大学河口海岸学国家重点实验室, 上海 200062

• 白雪莘
• 华东师范大学河口海岸学国家重点实验室, 上海 200062

• 葛灿
• 华东师范大学河口海岸学国家重点实验室, 上海 200062

• 张曼
• 浙江师范大学地理与环境科学学院, 金华 321004

• 张卫国
• 华东师范大学河口海岸学国家重点实验室, 上海 200062

• 摘要：对浙江省金华市义乌江采集的边滩沉积物柱样,进行了系统的环境磁学、粒度、地球化学分析,以探讨环境磁学方法诊断河流沉积物重金属污染的可行性.结果表明,柱样磁性特征由亚铁磁性矿物主导,其垂向变化受到粒度和早期成岩作用的一定影响.柱样中重金属Cr、Ni、Cu、Zn、Cd、Pb含量及其富集因子除底部外,自下而上呈增加趋势,指示了柱样上部存在人为来源的重金属污染.柱样沉积物磁性特征与重金属含量及其富集因子的垂向变化存在相似性,其中磁化率(χ)、频率磁化率(χ_fd%)和硬剩磁(HIRM)与Cr、Cu、Zn、Cd、Pb的含量具有显著的正相关关系,反映了磁性矿物与重金属具有相同的来源,或者细颗粒磁性矿物对重金属的吸附作用.上述结果表明,磁学方法可用于指示义乌江的重金属污染.但由于义乌江属于开放性的河流环境系统,磁性特征变化受多重因素影响,增加了利用磁学手段定量诊断重金属污染的复杂性.

• Abstract：In order to explore the feasibility of using magnetic properties as indicators for heavy metal pollution, magnetic, granulometric and geochemical analyses were conducted on a floodplain short core from Yiwu River in Jinhua City, Zhejiang Province, China. The results indicate that ferrimagnetic mineral dominates magnetic properties of the core. Particle size and early diagenesis influence the down-core changes in magnetic properties. Except the bottom layer, contents and enrichment factors of Cr, Ni, Cu, Zn, Cd and Pb show upward increasing trend due to anthropogenic input in the upper part of the core. It is found that variations of magnetic properties show similar patterns as those of heavy metals and their enrichment factors. In particular, magnetic susceptibility (χ)、frequency magnetic susceptibility (χ_fd%) and hard remanent magnetization (HIRM) show significant positive correlations with Cr, Cu, Zn, Cd and Pb contents. It is suggested that magnetic minerals may share a common source with heavy metals, or fine-grained magnetic minerals can absorb heavy metals. Therefore, magnetic parameters can be used as qualitative proxies of heavy metal pollution in sediments of the Yiwu River. However, due to the location of Yiwu River in an open river system, magnetic properties of sediments are influenced by a number of factors in addition to pollution input, which complicates the use of magnetic properties as quantitative indicators of heavy metal pollution.

• Key words：environmental magnetism  heavy metals pollution  river sediments  particle size  enrichment factor  Yiwu River

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