贵州草海湿地植物根际沉积物磷素形态特征

为分析草海湿地植物根际沉积物磷素形态特征,对24个根际沉积物样品中不同磷形态——Fe/A1-P(铁铝磷)、OP(有机磷)、Ca-P(钙磷)和Res-P(残渣态磷)的分布特征及其与金属、有机质的相关性进行了研究. 结果表明:湿地植物根际沉积物中w(Fe/A1-P)>w(OP)>w(Ca-P)>w(Res-P). w(TP)为114.2~863.9mg/kg,其中w(Fe/A1-P)为60.8~529.9mg/kg,占w(TP)的47.2%~83.5%,Fe/A1-P是磷的主要存在形态；w(OP)为12.2~195.1mg/kg,w(Ca-P)为6.1~205.7mg/kg,w(Res-P)为5.4~23.6mg/kg. 统计分析表明,w(TP)与w(Fe/A1-P)相关性较好(R=0.932,P<0.01)；而w(LOI)(LOI为烧矢量)与w(OP)相关性较弱(R=0.343). 主成分分析表明,草海湿地植物根际沉积物中磷主要来自生活污水和农业面源污染；磷素存在的形态特征主要受湿地植物根系泌氧及沉积物中w(Fe)、w(Mn)影响,其次是偏碱性水体. 

Study on Speciation of Phosphorus in Rhizosphere Sediments from Caohai Wetland in Guizhou Province

The phosphorus speciation and its relationships with the concentrations of some metals and organic matter were conducted. Totally 24rhizosphere sediment samples were collected from Caohai wetland in Guizhou Province. The results demonstrated that the concentrations in different phosphorus forms for sediment samples decreased as:Fe/A1-P>OP>Ca-P>Res-P. Concentrations of TP ranged from 114.2to 863.9mg/kg, and Fe/A1-P was the main speciation of phosphorus in the sediments with the concentration of 60.8-529.9mg/kg, accounting for 47.2% to 83.5% for TP. The contents of OP, Ca-P and Res-P ranged from 12.2to 195.1, from 6.1to 205.7and from 5.4to 23.6mg/kg, respectively. The statistical analysis showed a significant correlation between TP and Fe/A1-P (R=0.932, P<0.05), while the relationship between LOI (loss of ignition) and OP was not significant. The principle component analysis revealed that the pollution of phosphorus in rhizosphere sediment of Caohai wetland was mainly affected by the urban sewage and agricultural non-point sources. The prominent factor affecting phosphors speciation characteristics was associated with the oxygen secretion by the roots of the wetland plants and geochemical ingredients such as Fe and Mn. In addition, the alkalescent water in Caohai wetland was another factor affecting phosphorus speciation characteristics since alkalescent environment might accelerate the deposition of Ca.