合肥市南淝河不同排口表层沉积物磷形态分布特征

对合肥市南淝河不同排口处表层沉积物进行了采样,并采用修正后的标准测试程序SMT和钼锑抗紫外分光光度法测定了其中的总磷(TP)、无机磷(IP)、有机磷(OP)、铁/铝磷(Fe/Al-P)和钙磷(Ca-P),同时分析了各形态磷之间以及与沉积物有机质之间的相关性。结果表明,由于各排口附近不同的水动力条件,污染状况以及沉积环境,各排口表层沉积物总磷(TP)的质量分数存在显著差异,其值在771.23~3 065.36 mg/kg之间,除二里河排口(S15)沉积物磷以钙磷(CaP)为主外,其他采样点表层沉积物磷均以铁/铝磷(Fe/Al-P)为主,各形态P的最低值均在位于南淝河上游的S4点,TP、IP、Fe/Al-P的最大值均出现在位于望塘污水厂排口下游60 m处的S6点,潜在释放磷比例最大值在南淝河上游受农业面源污染影响较大的S3点。沉积物各形态磷之间存在着不同程度的相关性,各形态磷与有机质存在着显著的正相关。以上结果表明,南淝河沉积物磷形态分布特征受排口类型影响显著,其中城市污水处理厂尾水可能是受纳水体沉积物重要的磷源。

Distribution characteristics of phosphorus forms in the surface sediment from different discharging points along the Nanfei River in Hefei City, Anhui Province

Total phosphorus(TP), inorganic-phosphorus(IP), organic-phosphorus(OP), Fe/Al-bound phosphorus(Fe/Al-P) and Ca-bound phosphorus(Ca-P) in surface sediments of different discharging ports of Nanfei River in Heifei City, Anhui Province were measured based on the modified standard measurement and test(SMT) procedure and molybdenum-antimony spectrophotometry. The correlation between different phosphorus forms and organic matter content were also analyzed. The results show that the TP content in sediment varies from 771.23 to 3 065.36 mg/kg. Due to the differences of sedimentary environment, pollutant discharge and hydrodynamic condition in different discharging ports,the major phosphorus species of Erli River discharging points (S15) is Ca-P, others are Fe/Al-P. The minimum of all phosphorus species emerges at the upstream of Nanfei River (S4), the maximum of TP, IP and Fe/Al-P is at S6 located in 60 m away from the downstream of Wangtang discharging point, and the largest value of the potential release phosphorus is at S3 greatly influenced by agricultural non-point source pollution locating in the upstream of Nanfei River. Various forms of phosphorus in the sediments show different correlations each other, while the correlations between different phosphorus forms and organic matter contents are significantly positive. We concluded that the distributions of sediment phosphorus forms in Nanfei River was significantly influenced by the type of discharging points, and the effluent of municipal sewage treatment plant may be the important source of sediment phosphorus.