广州市主要湖泊沉积物磷的赋存形态

沉积物中磷的富集及其形态学特征是导致城市水体富营养化的重要因素之一。2016年-2017年对广州市8个主要城市湖泊花都湖、白云湖、东山湖、流花湖、天河湖、海珠湖、荔湾湖、麓湖表层沉积物的总磷（TP）及各形态磷的含量与分布特征进行了研究，并运用单因子污染指数法和生物有效性指数法对沉积物磷污染程度进行了评价。结果表明:广州市湖泊表层沉积物TP含量范围为368~5276 mg/kg，平均值为3277 mg/kg，其分布特征表现为东山湖>白云湖>花都湖>流花湖>天河湖>荔湾湖>麓湖>海珠湖。TP中以无机磷（IP）为主要存在形式，占TP含量的67.56%~87.44%，IP中又以铁结合态磷（Fe-P）为主，占TP含量的32.77%~60.24%，均值为42.88%。相关分析表明TP与Fe-P和有机磷OP，Fe-P与De-P，Ca-P与OP呈显著的正相关关系，表明其来源的相似性。通过分析可将广州市湖泊分为受珠江干流直接影响、接纳河涌入水、相对封闭和无明显外源输入的四类湖泊，表明输入源是决定广州市湖泊沉积物磷含量与分布特征的主要因素，工业废水、生活污水是主要污染源。单因子污染指数与生物有效性指数评价结果显示广州市湖泊沉积物整体处于重度磷污染水平。本研究对于科学评估广州市城区湖泊环境状况、潜在生态风险，有针对性的进行生态修复具有重要的意义。

Phosphorus Speciation in Sediments of Major Lakes in Guangzhou City

The enrichment of phosphorus in sediments and its morphological characteristics are one of key factors leading to eutrophication of urban water. The contents and distribution characteristics of total phosphorus and various phosphorus forms in surface sediments of huadu Lake, Baiyun Lake, Dongshan Lake, Liuhua Lake, Tianhe Lake, Haizhu Lake, Liwan Lake and Luhu Lake were studied from 2016 to 2017. Moreover, the pollution degree of surface sediments were assessed using the single-factor pollution index and bioavailability index. The results showed that the content of total phosphorus in the surface sediments had a range of 368.08~5276.33 mg/kg, with an average of 3277.46 mg/kg. Its distribution pattern showed an order of Dongshan Lake > Baiyun Lake > Huadu Lake > Liuhua Lake > Tianhe Lake > Liwan Lake > Luhu Lake > Haizhu Lake. The main fractions of phosphorus in sediments was inorganic phosphorus, accounting to 67.56%~87.44% of total content of phosphorus. As for forms of inorganic phosphorus, the major form was Iron-bound phosphorus, accounting for 32.77%~60.24% of TP, with an average of 42.88%. The results of correlation analysis showed that iron-bound inorganic phosphorus and organic phosphorus, iron-bound inorganic phosphorus and residual phosphorus, calcium-bound inorganic phosphorus and organic phosphorus were positive correlated significantly, indicating their similar sources. Based on the results of analysis, the studied lakes in Guangzhou City were classified four types: lakes affected directly by the main stream of the Pearl River, lakes received influx of rivers, lakes separated from other water body, and lakes with no significant exogenous input, showing a gradually weak trend for pollution degree. The content and distribution of phosphorus in sediment of lakes of Guangzhou City were mainly controlled by inputting sources, especially by industrial wastewater and domestic sewage. Overall, the phosphorus of sediments in lakes of Guangzhou City was in serious pollution level. The results of present study has great significance for environmental status and potential ecological risk assessment, and targeted ecological restoration for lakes in Guangzhou City.