Institution of Water and Environment Research, Dalian University of Technology, Dalian, 116024, China.
Institution of Water and Environment Research, Dalian University of Technology, Dalian, 116024, China; Key Laboratory of Coastal Science and Integrated Management, Ministry of Natural Resources, Qingdao, 266061, China.
Environ Pollut. 2022 Nov 1;312:120025. doi: 10.1016/j.envpol.2022.120025. Epub 2022 Aug 26.
Reservoirs located in middle and high latitudes freeze for months in winter, where the accumulation characteristics of pollutants are changed by superimposed influence of salt exclusion from ice on the surface and pollution release from sediments at the bottom. Taking total nitrogen (TN) of Biliuhe reservoir in Northeast China as an example, we developed a model to simulate TN accumulation characteristics influenced by ice and sediments during the freezing period (NACISF), and quantified contributions of TN from ice and sediments. Model parameters of ice and sediments were determined by laboratory freeze-up simulation experiment and sediment release flux simulation experiment, and water quality data were obtained from field investigations. Results showed that the annual average amount of TN input during the ice-covered period from 2015 to 2020 was 220.77 t, the output was 400.11 t, and the accumulated amount was 589.52 t. TN excluded from ice and released from sediments contributed 8.12% and 7.17% of the total TN inputs in winter, respectively. Analysis showed that the TN excluded from ice was positively correlated with ice thickness and initial TN concentration. The maximum ice thickness of Biliuhe reservoir had a 13 year cyclic feature, and the proportion of TN excluded from ice to the total TN inputs in different periods ranged from 10.68% to 17.30% (mean 13.18%). Meanwhile, TN accumulated seasonally as summer > autumn > winter > spring. The TN exclusion effect in 2050 would be weakened when considering the combined effects of climate change and human activities, with a reduction of about 40.85% compared to the current. It is concluded that the NACISF model took into account the influences of both ice and sediments, which provided a detailed understanding of the accumulation characteristics of TN during freezing period, and had important reference significance for water quality management in winter.
以中国东北的碧流河水库为例，我们开发了一个模型来模拟冰冻期（NACISF）受冰和沉积物影响的总氮（TN）积累特征，并量化了来自冰和沉积物的 TN 贡献。冰和沉积物的模型参数通过实验室冻结模拟实验和沉积物释放通量模拟实验确定，并从现场调查中获得水质数据。结果表明，2015 年至 2020 年封冰期的年平均 TN 输入量为 220.77t，输出量为 400.11t，积累量为 589.52t。冰排除的 TN 和从沉积物中释放的 TN 分别占冬季总 TN 输入量的 8.12%和 7.17%。分析表明，冰排除的 TN 与冰厚和初始 TN 浓度呈正相关。碧流河水库的最大冰厚具有 13 年的周期性特征，不同时期冰排除的 TN 占总 TN 输入量的比例在 10.68%至 17.30%（平均值为 13.18%）之间。同时，TN 季节性积累，夏季>秋季>冬季>春季。考虑到气候变化和人类活动的综合影响，到 2050 年，碧流河水库的 TN 排除效应将会减弱，与当前相比，减少约 40.85%。综上所述，NACISF 模型考虑了冰和沉积物的影响，提供了对冰冻期 TN 积累特征的详细了解，对冬季水质管理具有重要的参考意义。
