State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China.
China University of Petroleum-Beijing at Karamay, Karamay 834000, China.
Int J Environ Res Public Health. 2019 Jan 23;16(3):303. doi: 10.3390/ijerph16030303.
Dam construction changes the nutrient transport of a river system. Phosphorus is an important fundamental material in the global biochemical cycle and is always a limiting factor in the primary productivity of reservoirs. Extending the study of phosphorus in reservoirs is necessary given the dam construction in southwest China. Zipingpu Reservoir was chosen as the research site in this study. The form and distribution of phosphorus in the reservoir's surface sediments and overlying water were analyzed. The results showed that overall, the total phosphorus (TP) content of surface sediments in the Zipingpu Reservoir decreased from the tail to the front of the dam. The TP content ranged from 682.39 to 1609.06 mg/kg, with an average value of 1121.08 mg/kg. The TP content at some sampling points was affected by exogenous input. Inorganic phosphorus (IP) was the main form of phosphorus in surface sediments and had a proportion of 89.38%. Among the forms of IP, the content of Ca-P was larger than that of O-P; Ex-P, Fe-P, and Al-P had the lowest contents. Particulate phosphorus (PP) was the main form of phosphorus in the overlying water of the Zipingpu Reservoir and was strongly affected by hydrodynamic conditions. The content of total dissolved phosphorus (TDP) in the overlying water was relatively low. To further understand the risk of phosphorus release in the surface sediments in the reservoir, the rate and flux of phosphorus exchange at the sediment-overlying water interface were investigated through laboratory experiments. The results showed that both water temperature and pH significantly affected the sediment release rate, but the influence of water temperature was more significant. Acidic and alkaline conditions were conducive to the release of phosphorus from sediment, while a neutral environment was not. The release rate significantly increased with increasing water temperature, and a positive linear relationship was found between these two parameters. The sediment exhibited absorption characteristics when the water temperature was extremely low and exhibited releasing characteristics at a high temperature. These results could provide a theoretical basis for the management and protection of reservoir water environments.
水坝建设改变了河流系统的养分输送。磷是全球生物地球化学循环中的重要基础物质，一直是水库初级生产力的限制因素。鉴于中国西南地区的大坝建设，有必要对水库中的磷进行扩展研究。本研究选择紫坪铺水库作为研究地点。分析了水库表层沉积物和上覆水中磷的形态和分布。结果表明，总体而言，紫坪铺水库表层沉积物的总磷（TP）含量从坝尾向坝前逐渐降低。TP 含量范围为 682.39-1609.06mg/kg，平均值为 1121.08mg/kg。部分采样点的 TP 含量受到外源输入的影响。无机磷（IP）是表层沉积物中磷的主要存在形式，占 89.38%。在 IP 各形态中，Ca-P 的含量大于 O-P；Ex-P、Fe-P 和 Al-P 的含量最低。颗粒态磷（PP）是紫坪铺水库上覆水中磷的主要存在形式，强烈受水动力条件的影响。上覆水中总溶解磷（TDP）的含量相对较低。为了进一步了解水库表层沉积物中磷释放的风险，通过实验室实验研究了沉积物-上覆水界面磷交换的速率和通量。结果表明，水温和 pH 值都显著影响沉积物的释放速率，但水温和 pH 值对沉积物释放速率的影响差异较大。酸性和碱性条件有利于磷从沉积物中释放，而中性环境不利于磷的释放。随着水温的升高，释放速率显著增加，二者之间存在显著的正线性关系。当水温极低时，沉积物表现出吸附特征，而在高温时表现出释放特征。这些结果可为水库水环境保护的管理和保护提供理论依据。
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