长潭水库沉积物磷分布特征及污染成因分析

摘要

The total phosphorus ( TP) and various forms of phosphorus in surface sediments were measured by the sediment phosphorus form analysis method of the standard measurement and test ( SMT ) during the period from October 2011 to July 2012 at five sampling sites in the Changtan Reservoir, in order to explore the distribution characteristics of phosphorus in the sediments of deep lakes and reservoirs. The results show that the sediments of the Changtan Reservoir were in restoration conditions, especially in the middle and lower reaches and in the summer. The water contents in the sediments and the TOC content were low in the upper reaches and high in the middle and lower reaches. The TOC content was high in the spring and summer. The average value of the TP content in the Changtan Reservoir ranged from 0.56 to 0.79 mg/g, with a spatial distribution of relatively higher levels in the middle reaches and lower levels in the upper and lower reaches. The content of Fe/Al-bound phosphorus ( Fe/Al-P) ranged from 27% to 48% of TP, with an average value of 41%. The content of Ca-bound phosphorus ( Ca-P) ranged from 16% to 25% of TP, with an average value of 19%. The content of organic phosphorus (OP) ranged from 35% to 52% of TP, with an average value of 40%. Fe/Al-P accounted for the highest content of all phosphorus forms, and it was available for algae in the water. The main source of phosphorus pollutants of the Changtan Reservoir was the settlement of overlying water.%为揭示深水湖库沉积物磷的分布特征,运用沉积物磷形态标准分析法SMT,于2011年10月至2012年7月对长潭水库库区5个采样点沉积物中的TP和各形态磷含量进行了分析。结果表明：长潭水库沉积物处于还原状态,有利于Fe/Al-P的还原溶解,其中中下游还原性比上游强,夏季还原性最强。沉积物含水率和TOC质量比上游较低,中下游较高；春季和夏季沉积物中TOC质量比较高。长潭水库TP质量比平均值在0.56~0.79 mg/g之间,其空间分布特征是中游较高,上游和下游较低。其中,Fe/Al-P在TP中占27%~48%,平均为41%,Ca-P在TP中占16%~25%,平均为19%,OP在TP中占35%~52%,平均为40%。可见,各形态磷中Fe/Al-P所占百分比最大,有利于水体中藻类吸收利用。长潭水库沉积物磷污染主要来源为上覆水体中磷的沉降。