滇池湖泊磷负荷及其对水环境的影响

PHOSPHORUS BURDEN ON WATER BODY OF DIANCHI LAKE AND ITS IMPACT ON WATER ENVIRONMENT

磷是滇池湖泊富营养化的限制性营养元素。滇池湖泊磷负荷来源一般可分为外环境发生源输入的磷负荷和内环境发生源输出的磷负荷两大类。累积在滇池湖泊内的磷,主要分布在水体与底部沉积物中,滇池湖泊水体中总磷浓度由北向南含量降低,底部沉积物中P2O5含量分布由北向南呈递增趋势。底部0-3m的沉积物P2O5含量由上至下呈明显递减趋势,表明滇池湖泊磷负荷逐年加重。近几年资料显示滇池湖泊单位面积磷负荷达1.52g/m2·a,超过总磷公认允许负荷量中危险值的11.7倍,滇池已成为富营养型湖泊。控制滇池富营养化,在解决入湖磷外负荷的同时,对湖泊底部沉积物中磷内负荷也应予以高度重视。

Phosphorus stands as a controlling element of the nutrition of the water body of Dianchi lake to become a burden on it. The phosphorus burden is derived, as a rule, from two channels, input of phosphorus from the peripheral environment and output of phosphorus from the lake itself. Phosphorus is generally deposited in the water body and bottom sediments of the lake. The depositional level lowers progressively from north to south in the water body while elevates gradually from north to south in the bottom sediments. P2O5 contents of the 03m sediment of the lake bottom decrease evidently from top to bottom, suggesting that the phosphorus burden is aggravating yearly. According to newly data, the phosphorus burden of unit area in the lake has reached 1.52g/m2, 11.7 times more than acceptable limit, meaning that Dianchi has become a richly nutrient lake. Consequently, only by attaching importance to both the peripheral phosphorus input and the phosphorus output of the lake itself can its phosphorus nutrition be controlled.