外源砷输入对沉积物磷释放及形态转化的影响研究

选取云南阳宗海湖滨湿地沉积物为研究对象，外源砷浓度为0.00、0.01、0.05、0.10、0.25、0.50、1.00 mg/L，实验时间设置为短期（1～72 h）和长期（7～15 d），探究外源砷输入对沉积物磷释放及形态转化的影响规律特征。结果表明：外源砷浓度为0～0.25 mg/L时，沉积物对砷的吸附速率较快，以物理吸附为主；在0.25～1 mg/L时，沉积物对砷的吸附速率减缓，以化学吸附为主。随外源砷的浓度升高沉积物磷的释放量先升后降，外源砷浓度为0.25 mg/L时，沉积物磷的释放量达到最大值为0.092 mg/L，超过了地表水质量环境标准Ⅲ类水标准值。外源砷浓度的增加使沉积物中磷形态由惰性态向活性态转化，Al-P和Fe-P含量的增加与外源砷浓度呈显著相关性。外源砷进入会导致沉积物中磷的释放量增加及磷形态由非活性态向活性态转化，增加砷和磷的生态风险。

Effects of Exogenous Arsenic Input on Phosphorus Release and Morphological Transformation in Sediments

Selecting the sediments of Yangzonghai Lakeside Wetland in Yunnan as the research object. The concentration of exogenous arsenic was selected from 0.00, 0.01, 0.05, 0.10, 0.25, 0.50, and 1.00 mg/L. The experimental time was set to short-term (1−72 h) and long-term (7−15 d). Exploring the influence of exogenous arsenic input on phosphorus release and morphological transformation of sediments. The results show that when the concentration of exogenous arsenic is 0−0.25 mg/L, the sediment adsorption rate of arsenic is faster, mainly based on physical adsorption. At 0.25−1 mg/L, the adsorption rate of arsenic by sediments is slowed down, mainly by chemical adsorption. With the increase of exogenous arsenic concentration, the release amount of phosphorus in the sediment increase first and then decrease. When the concentration of arsenic is 0.25 mg/L, the maximum amount of phosphorus released from sediment is 0.092 mg/L, exceeding the standard value of Class III water standard for surface water quality and environmental standards. The increase of exogenous arsenic concentration causes the phosphorus form in the sediment to change from inert to active. The increase of Al-P and Fe-P content is significantly correlated with the concentration of arsenic. The entry of exogenous arsenic leads to an increase in the release of phosphorus from the sediment and the conversion of the phosphorus form from inactive to active, increasing the ecological risk of arsenic and phosphorus.