武汉东湖不同湖区底泥总磷含量及变化的研究

THE CONCENTRATION AND DYNAMICS OF SEDIMENT PHOSPHORUS IN VARIOUS LAKE REGIONS OF LAKE DONGHU

以武汉东湖为对象 ,研究了 1 998.0 3— 1 999.0 2期间不同营养水平湖区底泥中 (0—5cm ,5— 1 0cm)总磷的含量及季节动态。 6个站平均总磷含量为 1 .1 5mg/g ,同 80年代初相比 ,Ⅰ、Ⅱ站底泥中总磷含量分别增高 1 .42倍和 1 .0 3倍。受污水排放影响较重的 0站磷含量高达 2 .78mg/g,而受污水排放影响较小的Ⅳ、Ⅴ站仅分别为 0 .52mg/g和 0 .50mg/g。东湖底泥中磷年平均含量与湖水中磷年平均浓度相关系数极高 (r=0 .997,n =5,p <0 .0 2 )。通过对不同湖泊的底泥磷含量、水柱磷含量和外源负荷的比较和相关分析可以看出 ,水柱中磷含量较高 ,磷负荷较大的湖泊底泥中磷含量也高。可以预测 ,即使东湖的外源负荷得以控制 ,巨大的底泥磷内源负荷将会继续对东湖水质构成威胁。

The concentration and seasonal dynamics of phosphorus in the sediment (0—5cm,5—10cm) of Lake Donghu were studied at six stations with different nutrient levels. The sampling was taken by a core sampler monthly from March 1998 to February 1999. On the annual average of the six stations,P content in the sediment was 1.15mg/g. The P content in the sediment at Station Ⅰ(Ⅱ) in the present study was 1.42(1.03) times that in the early 1980s. At Station 0 where there was heavy sewerage discharge,the sediment P content was as high as 2.78mg/g,while at the less affected Stations Ⅳ and Ⅴ,it was only 0.52mg/g and 0.50mg/g,respectively. There was a good relationship between the P content of the sediment and the P content of the lake water (r= 0.997 ,n=5,p<0.02). By comparing the P content of the sediment and water column,and external P loading in some Chinese lakes,it appears that if the P content of the water column is high and external P loading is large,the P content in the sediment is generally also high. Predictably,the great P pool in the sediment will still be a threat to the water quality of the lake ecosystem even if the external loading is under control.