明湖湿地表层底泥中氮、磷和有机质污染水平及分布

Spatial Distribution and Pollution Assessment of TN、TP And TOM in Surface Sediments of Minghu Wetland

为了研究明湖湿地公园湖区内表层底泥中氮、磷营养盐和有机碳污染水平及分布现状,对明湖湿地5个区域26个采样点的表层(0~10 cm)底泥中总氮(TN)、总磷(TP)和总有机质(TOM)进行了测定、分析,结果表明:表层底泥TN含量介于285~4500 mg/kg间,均值为1779.6 mg/kg,分布趋势为西南(MS)区>东南(ME)区>东北湖响水河口(HK)>湖中心(MC)区>西北(MN)区;TOM含量介于17.13~189.30 g/kg间,均值为55.99 g/kg,空间分布与TN相似的格局;TP含量介于261~709 mg/kg间,均值为639 mg/kg,分布与TN、TOM有差异,最大值出现在HK区。TN与TOM二者间呈极显著正相关(r=0.951^*,p<0.01),TP与TOM之间关联性不明显(r=0.627)。结合有机指数(OI)和综合污染指数(FF)评价结果知,研究区内表层底泥营养盐已达中度污染水平,其中TN超标率较高,是明湖湿地表层底泥富营养化的主控因子。且湿地南部底泥中氮、磷营养盐及有机质污染属严重级别,污染程度超过最低生态毒性效应级别,存在较高的生态风险。

The contents of total nitrogen(TN),total organic matter(TOM)and total phosphorus(TP)in surface sediment of 26 sampling sites in five regions of Minghu Wetland were measured.The spatial distribution of nitrogen,phosphorus nutrients and organic matter in sediment of selected region(0-10 cm)were studied and analyzed,and the pollution status(level)was also evaluated.The results show that the TN content in surface sediment ranges from 285 to 4500 mg/kg,with an average value of 1779.6 mg/kg and the spatial distribution are MS>ME>HK>MC>MN.The TOM content ranges from 17.13 to 189.30 g/kg,with an average value of 55.99 g/kg,and the spatial distributions are similar to TN.The TP content ranges from 261 to 709 mg/kg,with an average value of 639 mg/kg,and the spatial distribution of TP are different with TN and TOM,which was shown as HK>ME>MS>MC>MN.There is a significant positive correlation between TN and TOM with a high homology between them.Comparatively,the coupling correlations of TP with TN and TOM are weaker,which indicates that the source and accumulation of TOM and TP in sediment are different.With the comprehensive analysis of organic and pollution index,the surface sediment of the whole lake has been polluted by nitrogen and phosphorus nutrients,especially in the southern region of the Wetland,in which the nitrogen,phosphorus nutrients and organic matter pollution in surface sediment belong to a serious level,and the pollution degree exceeds the lowest ecological toxicity effect level,with high ecological risks.Therefore,great attention should be paid to the follow-up research and prevention work.