过水性湖泊自净能力的动态变化

Self-purification ability of a water-carrying lake

通过对过水性湖泊骆马湖1991—2003年出、入湖口附近主要水质指标监测资料的分析,研究了湖泊湿地自净能力的变化情况。结果表明:1991—2003年,各采样点水质指标无显著变化,但出、入湖口水质差异显著,表明骆马湖目前尚有较强的自净能力;各采样点间主要水质指标的变异系数逐渐减小,表明湖泊对水体总氮、溶解氧、挥发酚、非离子氨、砷等主要富营养化物质和污染物的净化能力不断减小,湿地生态系统的自净能力显著下降。总氮、溶解氧及部分外源污染物指标在不同采样点间的变异系数可作为湿地生态系统自净能力与健康状况的重要参考指标。

By using the 1991-2003 monitoring data of water quality at 5 sampling locations distributed nearby the 2 entrances and 3 exits of the luoma Lake river ways, the self-purification ability of the lake was studied. The results showed that on the whole, the water quality near the exits was better and more steady-going than that near the entrances, indicating that the lake still had strong self-purification ability. The coefficients of variation of the water quality indices among the 5 sampling locations decreased gradually, suggesting that the purification rates of total nitrogen, dissolved oxygen, volatile hydroxybenzene, non-ionic ammonia, and arsenic in water body reduced remarkably, and the self-purification ability of the lake was weakened. The coefficients of variation of total nitrogen and dissolved oxygen and some exogenous pollutants among various sampling locations could be used as the reference indices of self-purification ability and health status of wetland ecosystems.