漫水河清远流域磷污染特征及富里酸对沉积物释磷的影响

探讨了漫水河清新区境内流域上覆水和沉积物中磷的空间分布特征，以及富里酸含量对沉积物释磷的影响。结果表明：5条农灌渠水体总磷质量浓度为0.87~2.83 mg·L⁻¹，超过地表水环境质量标准Ⅴ类水浓度限值；沉积物样本取自12个采样点，测得总磷含量为593.35~2 973.00 mg·kg⁻¹，其中铁结合磷(Fe-P)占比最高，为19.54%~64.47%；沉积物各采样点生物有效磷分布差异较大，占总磷比例平均为57.73%，说明研究农灌渠的沉积物潜在释磷能力大。相关性分析结果表明，TP含量与Fe-P、闭蓄态磷(Oc-P)、自生磷(De-P)含量间呈显著正相关，表明外源磷输入是导致沉积物磷含量升高的主要原因。投加外源富里酸的模拟实验结果表明，富里酸浓度升高会提高沉积物对磷的吸附能力，进而促进Fe-P的形成。

Characteristics of phosphorus pollution in Manshui River and the effects of fulvic acid on phosphorus release from sediments

In this study, the spatial distribution of phosphorus in the overlying water and sediments in the Qingxin District of the Manshui River was explored, and the effect of fulvic acid concentration on phosphorus release from sediments. The results showed that the total phosphorus concentrations at the 5 agricultural irrigation canals were 0.87~2.83 mg·L−1, which exceeded the surface water environmental quality standard V class water concentration limit; sediment samples were taken from 12 sampling points, the measured total phosphorus contents were 593.35~2 973.00 mg·kg−1, iron-bound phosphorus(Fe-P) accounted for the highest proportion of total phosphorus, which was 19.54%~64.47%; the distribution of biologically available phosphorus at each sampling point of the sediment was quite different, accounting for 57.73% of total phosphorus on average, which indicated that the potential release capacity of phosphorus from the sediments of the studied agricultural irrigation canals was large. The correlation analysis results showed that the significant positive correlations occurred between the content of TP and the content of Fe-P, closed storage state phosphorus(Oc-P), and authigenic phosphorus(De-P), indicating that the external source phosphorus input was the main reason for the increase of the phosphorus content of the sediment. The simulation experiment results of adding exogenous fulvic acid showed that the increase of the fulvic acid concentration could increase the adsorption capacity of the sediment for phosphorus, leading to Fe-P formation.