中文摘要：

酸可挥发性硫化物（AVS）与同步提取的重金属（SEM）之间的比例关系是控制缺氧性沉积物中重金属生物有效性及毒性的主要因素。采用野外采样及室内测定方法，对包头市南海湖表层沉积物和柱状沉积物的AVS、SEM、[SEM]/[AVS]进行了作图和分析比较。结果表明，黄河补水的污染、历史及现有生活污水排放、城市径流以及游船排放均提高了南海湖的重金属含量，并形成重金属含量高值区。水深的增加和现有生活污水的排放以及挺水植物的影响形成南海湖下游区域AVS明显高于上游。南海湖AVS垂向分布出现极大值下移和多个极大值的现象，不同于一般淡水湖泊。南海湖表层和垂向沉积物中AVS含量均远高于SEM含量，初步评价得出南海湖沉积物重金属是安全的。

英文摘要：

The ratio of acid volatile sulfide （AVS） to simultaneously extracted metals （SEM） is the key factor affecting the bioavailability and toxicity of heavy metals in anoxic sediments. By analyzing the variation of AVS, SEM and [SEM]/[AVS] of sediment in Nanhai Lake of Baotou city, it was found that the content of heavy metals in sediment of Nanhai Lake increased due to the water pumped from Yellow River, domestic sewage, municipal run-off and yacht waste release, thus forming the pattern of heavy metal distribution at present. Water depth increasing, domestic sewage influx and hydrophyte booming made the level of AVS in lake higher on downstream than upstream area. The vertical distribution of AVS in lake sediment core is different from the other fresh water lakes in China. The ratio of [SEM]/[AVS] in the surface and vertical sediment of Nanhai Lake was more less than 1, indicating that the sediment and the water in Nanhai Lake has not been contaminated by heavy metals.