杞麓湖表层底质营养盐的时空分布特征及评价

Spatiotemporal Distribution Characteristics of Surface Sediments Nutrients in Qiluhu Lake and Their Pollution Status Evaluation

通过现场调查和实验室分析方法对杞麓湖水体及表层底质各形态营养盐的时空分布特征进行研究。结果表明,在冬季和夏季杞麓湖底质及水体各营养盐浓度及分布具有较大差异。底质及水体中总氮浓度表现出湖周高、湖心低,且西南比东北高的分布特征;总磷浓度呈现出由西南向东北递增的趋势;无机磷浓度高于有机磷;无机磷中各形态磷的浓度由高到低依次是Ca-P>Fe/Al-P>NH4Cl-P。底质有机质浓度非常丰富,呈现出由湖周向湖心逐渐降低的趋势。有机指数和有机氮评价结果显示,杞麓湖各采样点有机指数相当高,全湖都处于严重污染状态,且整个湖体有机氮污染严重,西部湖湾为污染最严重的区域。杞麓湖底质营养盐浓度的控制刻不容缓。

The spatiotemporal distribution characteristics of the nutrients from overlying water and surface sediments in Qiluhu Lake were analyzed by field survey and laboratory analysis. The results showed that there were big differences in the content and distribution between nutrients in surface and water body in winter and summer. The contents of total nitrogen were high in lakeside, low in the center of the lake and decreased from southwest to northeast in surface and water body. The contents of total phosphorus （TP） increased from southwest to northeast. Inorganic phosphorus （IP） was the main fraction of TP. The contents of phosphorus fractions in IP from high to low were Ca-P, Fe/A1-P, NH4C1-P. The concentration of organic matter of sediments was abundant, which had the tendency declining from lakeside to the center. By organic matter index and organic nitrogen evaluation standards, the organic matter index at each sampling station in the lake was high and the lake was at the serious pollution category; the pollution of organic nitrogen in the whole lake was serious and the western bay of the lake was the most seriously polluted area. It is thus an urgent task to control the nutrients concentration of sediments in Qiluhu Lake.