中文摘要：

采用放射性核素^210Pb和^137Cs计年方法,建立了长江中游网湖近代沉积物的年代序列,并对网湖沉积物的粒度组成、磁性参数、重金属元素、花粉组合以及营养盐含量等指标进行了分析。根据沉积指标垂直分布的综合特征,结合湖区史料,重建了网湖100年来沉积环境的演变过程。通过对沉积指标与湖区人口变化、工农业产值等数据的比对,发现中华人民共和国成立以后沉积物中TOC和TN浓度与人口变化存在较高的相关性,相关系数分别达到0.8892和0.8928（P〈0.001）;沉积物中重金属元素富集序列、营养盐富集序列与孢粉含量的变化序列与湖区人类活动具有较好的耦合性。表明网湖沉积指标可以敏感地反映湖区的人类活动。

英文摘要：

The environmental evolution and human activities in the catchment of Wanghu Lake in the middle reaches of the Yangtze River was investigated by analyzing a 72 cm sediment core obtained in the centre of the lake. Dating sequence of the core was established based on radioisotopes ^137Cs and ^210pb. The proxies of the core sediments, such as grain-size, magnetic parameters, heavy metal, pollens, total organic carbon （TOC）, total nitrogen （TN）, and total phosphorus （TP）, were tested. The features of sediment vertical distribution in the core were compared with the records from historical social development documents of the surrounding areas, including population size, total industrial and agricultural output value. The results show that since 1878, the Wanghu Lake environment has evolved in three stages. （1） Before the 1950s, both TOC and TN concentrations were low and stable, which indicates that the TOC and TN of sediment were mainly from the natural soil nutrient cycling in surroundings. The lake environment continued the process of natural evolution, and basically maintained the original eco-environment. （2） From 1950 to 1970, traces of human activities were evidently found in the natural sediments of the lake. During the period, the average grain-size of the sediments became larger, and TOC and TN concentrations increased substantially. High value of TP concentrations is observed, and pollen concentration increased as well. （3） After 1970, the lake was disconnected from the river, so it was transformed from an open lake to a closed one. The evolution of the lake environment was then dominated by human activities which has been reflected in the indicators of the sediments： the average grain-size of the sediments increased continuously; TOC and TN concentrations increased substantially; shrub and herb pollen concentrations in the pollen combination mutated and increased; and the proportion of Myriophyllum and Pediastrum, which indicate the level of lake nutrients, increased significantly.