太湖流域农村黑臭河流表层沉积物中磷形态的分布特征

为揭示太湖流域农村黑臭河流表层沉积物中磷形态的分布特征以及各形态磷之间的相关性,以宜兴市周铁镇掌下浜(北段)为例,沿河流从上游到下游河口共采集了13个表层沉积物样,应用欧洲标准测试委员会框架下发展的SMT分离方法对沉积物中磷形态进行分析,揭示了沉积物中磷形态的分布特征及相关性,并对表层沉积物中磷的生物有效性加以分析。结果表明:沉积物中总磷(TP)含量极高,平均含量为2 598.30 mg·kg^-1;无机磷(IP)是各采样点沉积物中磷的主要成分,占TP的72.95%~85.32%;钙磷(Ca-P)是沉积物中主要的无机磷形态,占IP的69.63%~84.03%。TP与Ca-P含量具有极显著的相关性(P<0.01,n=13),钙磷(Ca-P)和铁铝结合态磷(Fe/Al-P)含量分别与有机磷(OP)和无机磷(IP)含量均具有较好的相关性,两两均达到极显著水平(P<0.01,n=13),TP与Fe/Al-P+OP呈极显著正相关关系(P<0.01,n=13)。表层沉积物中高含量的TP除受外源性污染物影响较大外,与逐渐严重的内源磷负荷也有关。

Distribution Characteristics of Phosphorus Fractions in Surface Sediments from a Rural Malodorous Black River in Taihu Lake Watershed

In recent years, water eutrophication in the rural rivers in the Talhu Lake watershed has caused increasing public concerns. However, there is little information available on phosphorus fractions in the surface sediments. Herein, thirteen surface sediment samples were collected from the upper reach till the lower reach along the north section of Zhangxia River near Zhoutie Town, Yixing, a rural malodorous black river running into the Taihu Lake. Phosphorous fractionation was preformed following the SMT protocol. Bio-availability of phosphorous fractions was also assessed. The concentrations of TP were very high, with an average concentration of 2 598.30 mg·kg^-1. Inorganic P(IP) was the main fraction of TP, accounting for 72.95%~85.32%. Ca-P was 69.63%~84.03% of IP, which ranged between 1 064.09 mg·kg^-1 and 2 484.84 mg·kg^-1. TP was significantly correlated with Ca-P(P<0.01, n=13). Ca-P and Fe/Al-P had significant correlation with OP and IP(P<0.01, n=13), respectively. TP was also significantly and positively correlated with Fe/Al-P and OP(P<0.01, n=13). Our results suggest that high TP in surface sediments is due to both heavy exogenous P inputs and progressively intensified endogenous P pollution.