南漪湖沉积物磷的赋存形态及对上覆水的影响  

Characteristics of phosphorus fractions in sediments and its influence on the water quality of Lake Nanyi

作　　者：谢发之[1] 罗锟 朱元荣[2] 李海斌[1] 李国莲[1] 刘站 李婉璐 蔡格格 XIE Fa-zhi;LUO Kun;ZHU Yuan-rong;LI Hai-bin;LI Guo-lian;LIU Zhan;LI Wan-lu;CAI Ge-ge(Anhui Provincial Key Laboratory of Environmental Pollution Control and Resource Reuse,Anhui Jianzhu University,Hefei 230601,China;State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences,Beijing 100012,China)

机构地区：[1]安徽建筑大学,环境污染控制与废弃资源化利用安徽省重点实验室,安徽合肥230601 [2]中国环境科学研究院,环境基准与风险评估国家重点实验室,北京100012

出　　处：《中国环境科学》2022年第11期5318-5327,共10页China Environmental Science

基　　金：国家自然科学基金资助项目(42277075,41877380);国家重点研发计划项目(2021YFC3201005);安徽省重点研发计划项目(202004i07020006);住建部科学技术计划项目(2019-K-138)。

摘　　要：以宣城市南漪湖为例,采用改进的无机磷分级提取方法对全湖共39个点位沉积物中磷(P)赋存形态进行系统研究,并分析其与上覆水体、间隙水等相互关系.结果表明,南漪湖水体磷污染水平已经处于高位,沉积物间隙水磷与上覆水体磷空间分布特征具有密切关系.南漪湖沉积物中总磷(TP)含量变化范围为463.3~1016.6mg/kg,其中各形态磷空间分布具有明显的差异性,与外源磷输入等密切相关.赋存形态含量大小、相对比例顺序依次为:钙结合态磷(Ca-P)>铁结合态磷(Fe-P)>铝结合态磷(Al-P)>还原剂可溶性磷(RS-P)>残渣态磷(Res-P)>弱吸附态磷(L-P).沉积物中TP含量与Fe-P、RS-P、Res-P极显著正相关,与L-P含量显著正相关.外源磷输入和水产养殖对南漪湖沉积物内源磷中Fe-P和RS-P贡献可能较大.南漪湖沉积物内源磷对上覆水体的潜在风险较高,其中生物有效性较高的L-P、Al-P、Fe-P和Rs-P的总和相对比例可达60%左右.沉积物中磷形态与间隙水磷浓度关系较密切,其中Al-P、Ca-P对间隙水中磷迁移转化具有重要影响.南漪湖主要出入湖河口沉积物磷的吸附解吸平衡浓度(EPC0)变化范围为0.009~0.014mg/L,均表现为EPC0<总溶解性活性磷浓度(SRP),主要河口沉积物目前仍为外源磷输入的汇.Fractions of phosphorus(P)in sediments were investigated by using an improved sequential extraction procedure for inorganic P in 39 sampling sites from Lake Nanyi,Xuancheng city,Province of Anhui,China.The relationships between P fractions in sediments,concentrations of P in the overlying water and pore water were analyzed.Results show that the concentrations of total P(TP)in the overlying water of Lake Nanyi were in a high level,which were closely related with concentrations of TP in the pore water.Contents of TP in the sediments of Lake Nanyi ranged from 463.3 to 1016.6 mg/kg.Spatial distribution of P fractions in sediments was significant difference,which was closely related with the inputs of external P.Contents and their relative percentages were decreased in the order that calcium-bound P(Ca-P)>iron-bound P(Fe-P)>aluminium-bound P(Al-P)>reduced soluble P(RS-P)>residual P(Res-P)>loosely absorbed and dissolved P(L-P).Contents of TP in the sediments were significantly correlated with Fe-P,RS-P,Res-P and L-P.Input of external P and aquiculture was likely contributed large of internal Fe-P and RS-P in sediments from Lake Nanyi.The potential risk of internal load of P in sediments was high,which bioavailable P fractions including L-P,Al-P,Fe-P,and Rs-P accounted for 60%approximately.Concentrations of P in pore water were closely related with the spatial distribution characteristics of P fractions in sediments.The main compositions of P including Al-P and Ca-P have important influence on migration and transformation of P in the pore water.The zero equilibrium P concentration(EPC0)value of the sediments from the area of main river estuary ranged from 0.009 to 0.014 mg/L,which showed that the EPC0<Soluble Reactive P(SRP).This result showed that the sediments in the area of main river estuary were still the sink for the input of external P.

关 键 词：长江中下游 南漪湖 沉积物 磷赋存形态 迁移转化 富营养化风险 

分 类 号：X524[环境科学与工程—环境工程]