云南安宁磷矿区水系沉积物磷赋存形态及分布特征
Chemical Forms and Distribution Characteristics of Phosphorus in the Sediments of the Anning Phosphate Mining Area, Yunan Province
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摘要: 磷污染是水污染的重要组成部分，因其可造成水体富营养化、水质下降，从而引起人们的广泛关注。研究沉积物中不同磷赋存形态及其分布特征有助于了解沉积物中磷的行为特征及迁移能力，从而为水体富营养化防治提供支撑。磷矿的开采、冶炼对矿区内水资源环境可能产生严重影响，本文以安宁磷矿区内河流、水库为研究区域，分析了不同水系沉积物磷元素赋存形态及分布特征，并对其生态风险进行评估。采用X射线荧光光谱法测定研究区水系沉积物总磷（TP）含量，并基于顺序提取及Hupfer改进的磷形态分析方法，将研究区各水系沉积物中磷分为弱吸附态磷（NH4Cl-P）、可还原态磷（BD-P）、金属氧化物结合态磷（NaOH-P）、钙结合态磷（Ca-P）、残渣态磷（Res-P）等5种形态，采用单因子污染指数法对其进行生态风险评估。结果表明：研究区水系沉积物样品中TP含量范围为567.6~48115.5mg/kg，NH4Cl-P含量范围为0.07~115.2mg/kg，BD-P含量范围为8.84~802.5mg/kg，NaOH-P含量范围为21.3~3129.5mg/kg， Ca-P含量范围为12~45098mg/kg，Res-P含量范围为28.5~515.4mg/kg。研究区各水系沉积物样品磷形态具有相似的分布特征，即磷主要以Ca-P和NaOH-P形态存在，其他磷形态的相对含量大小顺序为NH4Cl-P<BD-P<Res-P。单因子污染指数评价结果表明，各水系沉积物中磷以重度污染为主。生物有效磷（BAP）污染评价结果表明，各水系沉积物中磷污染程度有所降低，但河流沉积物中磷仍以重度污染为主，磷释放风险较大，建议加强对磷矿区河流磷污染的监测与评估。Abstract: The chemical forms and content of phosphorus in sediments are the important basis for exploring bioavailability, migration, and transformation of phosphorus in sediments accurately. To assess and evaluate phosphorous pollution from a phosphate mine, the phosphorus chemical forms in the sediment were determined by a suggested combined method and studied by the phosphorus classification method. The results show that the total phosphorus content all reached the lowest level of ecotoxic effect, and 56.7% of samples reached the serious level of ecotoxic effect. Therefore, it is suggested to strengthen the monitoring and assessment of river pollutants in phosphate mining areas. The BRIEF REPORT is available for this paper at http://www.ykcs.ac.cn/en/article/doi/10.15898/j.ykcs.202209050164.
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