利用柱状沉积物采样器和Peeper间隙水采集器分别获取南四湖不同湖区原位柱状沉积物和间隙水,在分析沉积物磷形态和间隙水PO4 3-P空间分布特征的基础上,比较离心法和Peeper法获取间隙水的差异性,并探讨其沉积物各磷形态组分与间隙水PO4 3-P的相关性.研究表明,南四湖4个湖区沉积物各磷形态含量由大到小的顺序是IP〉Ca.P〉Fe/A1.P〉OP〉L-P,其中,IP平均含量最高,约占TP的71%~90%在空间分布上,不同湖区各磷形态组分含量差异显著,尤其以Fe/Al-P含量差异最大,总体呈现由北向南依此递减的趋势,这与南四湖北部距离济宁市区较近,受污染较重有关.各磷形态组分在垂向分布上比较复杂,既有随深度增加的,也有随深度减小的,规律性不明显,这可能与南四湖本身是一个航运型和季节性湖泊,常年受大型航运船只的扰动、季节性降水、洪涝灾害以及突发性污染事件等各因素的影响有关.Peeper法及离心法获取间隙水的研究结果表明,南阳湖区(NSHl)间隙水PO4 3-P含量最高,平均值约0.4mg·L-1,4个不同湖区,PO4 3-P含量在垂直方向均具有先增加后降低的趋势,且浓度均高于上覆水浓度,具有向上覆水释放的趋势.Peeper法获取间隙水中PO4 3-P的平均含量比传统离心法高出约20%,且相关性很好,两种方法获取间隙水的研究结果一致表明,南四湖沉积物Fe/A1.P和Ca.P与间隙水PO4 3-P的含量具有显著正相关.
Interstitial water and intact sediment were collected by cylindrical sampler and Peeper from different zones of Nansi Lake. Sediment phosphorus forms and PO4 3-P in interstitial water were measured and pore water obtained by centrifugation and Peeper method was compared. Correlation between sediment phosphorus forms and PO4 3-P concentrations in interstitial water was then analyzed. Results showed that the descending order of different phosphorus fractions in sediments of the four sub - lakes was IP 〉 Ca-P 〉 Fe/A1-P 〉 OP 〉 LP, and the average contents of IP was the highest, accounting for Tl% -90% of the TP. Contents of sediment phosphorus forms were different significantly in space, especially the Fe/A1-P, which generally decreased from north to south. This was due to the pollution from the nearby Jining city to the north Nansi Lake. The vertical distributions of phosphorus fractions did not have a consistent distribution pattern. This may be due to the disturbance of large shipping vessels, seasonal variation in precipitation, flooding events, accidental environmental pollution accidents, etc. Results of pore water obtained from Peeper and centrifugation showed that the contents of PO4 3-P in Nanyang Lake ( NSH1 ) were the highest, and the average value was about 0.4 mg· L - 1. The concentrations of PO4 3-P increased and then decreased, and concentrations in pore water were higher than those of overlying water, reflecting a possible diffuse trend for PO4 3-P in the four zones of Nansi Lake. In addition, average PO4 3-P concentrations in interstitial water from Peeper method were about 20% higher than those from centrifugal method with good relevancy. In conclusion, results from the two methods both indicated that contents of sediment Fe/AI-P and Ca-P positively correlatedwith PO43 - -P in the interstitial water of Nansi Lake.