太湖湖滨带底泥氮、磷、有机质分布与污染评价

Nitrogen,phosphorous and organic matter spatial distribution characteristics and their pollution status evaluation of sediments nutrients in lakeside zones of Taihu Lake

采集了环太湖湖滨带表层(0～10cm)底泥,研究分析了湖滨带底泥中有机质(OM)、总氮(TN)、总磷(TP)的空间分布特征,并对太湖湖滨带底泥进行营养评价.结果表明,湖滨带底泥中OM含量在1.42%～9.96%之间,空间分布趋势为:东太湖>竺山湾>贡湖>梅梁湾>南部沿岸>东部沿岸>西部沿岸;TN含量在458～5211mg/kg之间,空间变化趋势为东太湖>竺山湾>东部沿岸>贡湖>南部沿岸>梅梁湾>西部沿岸;TP含量在128.56～1392.16mg/kg之间,空间变化趋势为竺山湾>梅梁湾>东太湖>南部沿岸>贡湖>东部沿岸>西部沿岸,OM与TN分布趋势相似,TN与OM之间极显著正相关(r=0.903,P<0.01),TP与OM之间弱相关(r=0.073,P<0.332).结合综合污染指数和有机指数评价法可知,太湖湖滨带底泥环境质量整体较好,氮、磷污染除东太湖和竺山湾属重度污染外其他各区属轻中度污染;有机污染除东太湖外大部分区域属较清洁区.

Top layer（0~10 cm） samples in the lakeside zones of Taihu Lake were collected.The content of organic matter（OM）,total nitrogen（TN）,and total phosphorus（TP） were measured,and finally pollution assessment for top layer sediments was made.The results showed that the OM levels in top layer sediments in lakeside zones of Taihu Lake ranged from1.42% to 9.96%.The spatial change trend of OM content of the top layer sediment in the decrease order as follows： Eastern Taihu Lake,Zhushan Bay,Gonghu Bay,Meiliang Bay,South shore,East shore,and West shore.TN content of the top layer sediment had a similar spatial distribution regularity with OM,ranged from 458mg/kg to 5211mg/kg.The spatial change trend of TN in the decrease order as follows： Eastern Taihu Lake,Zhushan Bay,East shore,Gonghu Bay,South shore,Meiliang Bay and West shore.TP content of the top layer sediment ranged from 128.56mg/kg to 1392.16 mg/kg.The spatial change trend of TP in the decrease order as follows： Zhushan Bay,Meiliang Bay,Eastern Taihu Lake,South shore,Gonghu Bay,East shore and West shore.OM content and TN content had very significant positive correlation（r=0.903,P0.01）,but no obvious correlation with TP content（r=0.073,P0.332） in the top layer sediments.Based on comprehensive pollution index and organic index,the environmental qualities of sediments in the whole lakeside zones still belonged to clean category.Except for Eastern Taihu Lake and Zhushan Bay seriously polluted by N,P and the other areas were mild-to-moderate pollution.The organic pollution of most areas was under lower pollution level except East shore.