• 关键词：河流底泥  任港河  重金属污染  磁学诊断  粒度

• 基金项目：国家自然科学基金(No. 41001355, 40771201);江苏省高校自然科学基金(No. 09KJD170001);南通市科技创新计划项目(No. S2009040)

• 董艳
• 1. 华东师范大学河口海岸学国家重点实验室, 上海 200062;
  2. 南通大学地理科学学院, 南通 226007;
  3. 南通大学地理工程技术研究所, 南通 226007

• 张卫国
• 华东师范大学河口海岸学国家重点实验室, 上海 200062

• 钱鹏
• 1. 南通大学地理科学学院, 南通 226007;
  2. 南通大学地理工程技术研究所, 南通 226007;
  3. 华东师范大学地理系, 地理信息科学教育部重点实验室, 上海 200062

• 蒋庆丰
• 1. 南通大学地理科学学院, 南通 226007;
  2. 南通大学地理工程技术研究所, 南通 226007

• 刘莹
• 华东师范大学河口海岸学国家重点实验室, 上海 200062

• 董辰寅
• 华东师范大学河口海岸学国家重点实验室, 上海 200062

• 摘要：以江苏省南通市任港河底泥柱样为研究对象,在系统的环境磁学、粒度、重金属及总有机碳含量分析的基础上,探讨了沉积物重金属污染的环境磁学诊断的可行性.结果表明,表层12 cm以上样品中重金属Pb、Zn、Cu、Ni含量超出江苏省土壤背景值,剔除粒度影响后,重金属含量"上高下低"的特征仍很明显.该底泥柱样沉积物的磁性特征为亚铁磁性矿物所主导,亚铁磁性矿物含量在表层12 cm 以上沉积物要高于下部沉积物,其含量在沉积物上部的升高受到污染的影响.磁化率(χ)、饱和等温剩磁(SIRM)和非磁滞剩磁磁化率(χ_ARM)与Pb、Zn、Cu、Ni含量有显著的正相关关系(r≥0.74,p<0.01,n=54),可用于定性评价任港河底泥的重金属污染程度.但因受到磁性矿物的来源和成岩作用等因素影响,表层沉积物亚铁磁性矿物与重金属含量升高不尽一致,利用磁性参数定量诊断重金属含量仍需慎重.

• Abstract：To explore the feasibility of using magnetic properties as indicators for heavy metal pollution, magnetic properties, particle size, heavy metal concentrations and total organic carbon contents were investigated for a sediment core from the Rengang River in Nantong City, Jiangsu Province. The results indicate that Pb, Zn, Cu and Ni contents are enriched in the top 12 cm layer, which are higher than the soil background values of Jiangsu Province. After normalizing the effect of particle size, heavy metal contents are still higher in the upper part than the background values. It is found that ferrimagnetic mineral dominates the magnetic properties in the sediment core. Magnetic mineral contents are higher in the upper 12 cm of the sediments than those below due to anthropogenic input. Magnetic susceptibility (χ), saturation isothermal remanent magnetization (SIRM) and susceptibility of anhysteretic remanent magnetization (χ_ARM) display significant positive correlations with Pb, Zn, Cu and Ni concentrations(r≥ 0.74,p<0.01,n=54), suggesting that magnetic parameters can be potentially used as qualitative proxies of heavy metal pollution in the river sediments. However, the changes in magnetic mineral contents are not consistently synchronous with heavy metal concentrations in the upper 12 cm of the sediments, due to the effects of their sources and diagenesis. Therefore, it should be cautious to examine heavy mental contents quantitatively using these magnetic parameters.

• Key words：river sediment  Rengang River  heavy metal pollution  magnetic diagnosis  particle size

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