龙感湖小流域元素时空分布及湿地拦截功能探讨

Temporal and spatial distribution of chemical elementsin small catchment, and buffer function of wetland inLongganhu Lake, China

众所周知,湖滨湿地是湖泊环境的屏障,它对流域入湖物质具有吸收与拦截作用。通过长江中游龙感湖湖滨湿地和湖泊沉积物中元素含量在时间序列上的对比研究,发现湖滨湿地对入湖主要重金属元素确有明显拦截作用;但对于化学性质活跃,易以溶液态迁移的元素如Fe、Mn等不具备明显的拦截功能。人类活动对湿地的破坏,减弱了湿地对流域入湖物质的拦截功能,加速了湖泊生态环境的恶化。

Wetland is the conjunction of lake and terrene where materials pass by and human activity is concentrated . From the aspect of material transportation and cycling in terrene-lake system, wetland is the buffer area where sand and mud, heavy metals, pollutants and nutrients are carried. In this paper, we provide a case study of wetland buffer function. In Wanglinghe catchment, a small sub-catchment of Longganhu Lake in middle reach of Yangtze River, we took three cores L7, L3 and LH represents alluvial, wetland and lake sediment respectively. Variations of chemical elements concentration in three cores show the temporal and spatial distribution of the elements in the sub-catchment. Based on it, we have found that it is significantly for major heavy metal such as Cr, Cu et al. in wetland buffers area, but it has a little buffer function to some active elements such as Fe and Mn which are always transported as solution. Human activity not only influences the elements distribution, but also weakens the buffer function of wetland.