滇池福保湾沉积物不同形态磷的垂向分布

应用SMT连续提取法分析滇池福保湾柱状沉积物的磷(P)形态,探讨P形态的垂向分布特征.沉积物中总磷 (TP)含量高,最高达4　200 mg/kg, 无机磷 (IP)是TP的主要部分,占TP的52%～91%, 铁/铝结合态磷 (Fe/Al-P)是IP的主要部分,占IP的55%～94%.同一湖区不同采样点的沉积物P形态的垂向变化不同，湖湾北端近河口处和南端远离河口处的沉积物中Fe/Al-P, IP, 有机磷 (OP)和TP含量随深度增加而增加,6～11 cm 层的含量最高,这与近年来入湖河流污染负荷削减和河堤阻隔导致P入湖量减少有关.河口处沉积物的钙结合态磷 (Ca-P)含量随深度增加而增加,最南端沉积物的Ca-P含量随深度增加而减少.离河口较远的沉积物中,Fe/Al-P, IP, OP,TP和Ca-P均随深度增加而减少.各点沉积物P形态的变化受该点人类活动带来的入湖污染物量的影响较大,距河口最远处的沉积物中P形态随深度变化不如其他点明显. 

Vertical Distribution of Various Forms of Phosphorus in the Sediments of Fubao Gulf, Dianchi Lake

SMT continuous extracting method was used for the analysis of the phosphorus (P) forms of columnar sediments from Fubao Gulf, Dianchi Lake. The vertical distribution of P forms in sediments was then discussed. The sediment has high total phosphorus (TP) content, with maximum value of 4　200　mg/kg. inorganic phosphorus (IP) is the major part of TP, which is about 52%～91% of TP. P bound to Al, Fe and Mn oxides and hydroxides (Fe/Al-P) is the major part of IP, which is about 55%～94% of IP. The vertical distribution of P forms in the same lakearea has various regularities. In the river mouth and the south endpoint of the gulf, the content of Fe/Al-P, IP, organic phosphorus (OP) and TP decreased as the depth of sediment increased. The content of Fe/Al-P, IP, OP and TP inthese points was largest in the layer from 6 to 11 cm under the water/sediment interface. This maybe caused by the reduction of pollutants load entering the river and the partition of pollutants load entering the lake by the river levee. The P associated with Ca (Ca-P) content increased as the sediment depth increasedin the river mouth area but decreased as the sediment depth increased in the south of the gulf. This illustrated that the change of P forms in sediment of every site was affected by the pollutants load entering the lake by the anthropogenic action. And the change of P forms in sediment of the southmost point in the gulf was less than other points.