玄庙观水库表层沉积物磷形态及正磷酸盐释放风险特征研究

在高磷矿区域深大水库缺乏相关研究与报道的背景下,为给深大水源水库的管理提供科学依据,对宜昌市黄柏河流域玄庙观水库的沉积物及其上覆水的理化特征进行了研究。结果表明:(1)玄庙观水库表层沉积物总磷(TP)含量变化范围为5 356.0~9 631.5 mg/kg,各磷形态含量表现为:钙磷(Ca-P)"有机磷(OP)"铁铝磷(Fe/Al-P),其中,Ca-P为TP的主要成分,占TP的86.4%~93.0%;(2)受外源磷矿输入的影响,TP和总碳(TC)表现出相同的整体变化趋势,即从库首到库尾逐渐增大,而有机质(TOC、TN、OP)的来源类似于深大湖泊,主要源自内生生物的沉积作用,各采样点无显著性差异;(3)沉积物-水界面存在明显的正磷酸盐(PO_4~(3-)-P)浓度梯度,释放通量为0.41±0.09~0.86±0.14 mg/(m~2·d),数据统计分析表明内源磷释放通量与TP、Ca-P浓度具有显著正相关性,且为该区域的第一主成分因素。

Phosphorus Fraction and Orthophosphate Diffusion Flux from Surface Sediments of Xuanmiaoguan Reservoir

There is little information on deep reservoirs with phosphate mining and their management. Physical and chemical characteristics of sediment and its interactive water in Xuanmiaoguan Reservoir of Huangbai River basin,located in Yichang City,were studied. The results showed that (1) the total phosphorus (TP) contents ranged from 5 356. 0 - 9 631. 5 mg /kg. The P-fraction concentrations were ranked in the following order: P associated with calcium (Ca-P) "Organic P (OP) "P bound to aluminum,ferrum oxides and hydroxides (Fe /Al-P). Ca-P,accounting for 86. 4％ - 93. 0％,was the main component of TP. (2 ) Due to the input of phosphate ore from exogenous,TP and total carbon (TC) increased from the head to the end of the reservoir. The organic matter (TOC,TN,OP) are mainly derived from the deposition of endogenetic organisms,which is more similar to deep lakes. (3) A gradient of the orthophosphate (PO3-4 -P) occurred at the sediment-water interface and its diffusion flux ranged from 0. 41±0. 09-0. 86±0. 14 mg /(m2·d),which indicated a great ecological risk of the reservoir. Statistical analysis showed that P diffusion flux was the first component of this basin,which was related to TP and Ca-P contents.