水库季节性锰污染的生物地球化学模拟研究

Water pollution in water supply is harmful for resident health and industrial products. Many reservoirs in China appear seasonal manganese pollution in recent years, threatening the drinking water safety and industrial benefits. The reservoir manganese pollution has become an urgent water resources and environmental problems. The manganese pollution release and migration involve complex biogeochemical reactions, which are affected by the reservoir hydrology, water quality and aquatic ecological processes. Reservoir manganese pollution models are useful tools for manganese pollution impacts analysis and manganese pollution predictions. In this study, we aim to develop a reservoir manganese pollution model, and apply it in a Qingdao drinking water sources - Wangjuan reservoir. This study has three parts: ①Dynamic monitoring of nutrients, algae and manganese in layers were planned to analyze the temporal and spatial distribution of manganese pollution and provide verification for modelling. ②A one-dimensional manganese biogeochemical model was planned to be developed with improving manganese release modelling by experiments. ③Quantitative evaluation of impacts on reservoir manganese pollution of hydrological regimes, water intaking ways, nutrients and algae were planned. This study can address key scientific issues of biogeochemical simulation of reservoir manganese pollution, provide scientific supports for reservoir manganese pollution control and governance, which is of great significance in water environmental science and great value in water pollution control application.

水源中的锰污染对人体健康和工业产品生产有严重危害。近年来，我国许多水库出现了季节性锰污染现象，成为了日益突出的水资源和水环境问题。锰污染的产生和运移涉及到复杂的生物地球化学反应，受到水库水文、水质和水生态过程的影响。水库锰污染的数值模型可以用于锰污染的影响因素分析和发展趋势预测，是水库锰污染研究和治理的重要工具。本课题以构建水库锰污染生物地球化学模型为目标，选取青岛市饮用水源地--王圈水库作为研究对象，研究内容包括：①对水库锰污染和相关水质指标进行动态监测，分析锰污染的时空分布规律，为数值模拟提供可靠验证；②构建水库锰污染的生物地球化学模型，结合室内模拟试验改进沉积物锰释放的模拟；③利用模型定量计算水库水文情势、取水方式、氮磷污染和藻类等环境因素对锰污染的影响。课题研究可以解决水库锰污染的生物地球化学模拟的关键科学问题，为水库锰污染控制和治理提供科学依据，具有重要的科学意义和应用价值。

水库的季节性锰污染现象是近年来日益突出的水资源和水环境问题。锰污染的产生和运移涉及到复杂的生物地球化学反应，水库锰污染的数值模型可以用于锰污染的影响因素分析和发展趋势预测，是水库锰污染研究和治理的重要工具。本课题以构建水库锰污染生物地球化学模型为目标，选取青岛市饮用水源地--王圈水库作为研究对象，取得了以下研究成果：（1）总结了水库锰污染的时空分布规律，夏季丰水期时水深较深处形成水温分层，底层的可溶性Mn、氨氮和总磷含量显著增加，锰污染严重，水库Mn含量超标的主要原因是在水库水深较大的区域，由于水体出现温跃层，上下水体之间缺乏交换，底层水体中的DO逐渐被耗尽使得底层水体从氧化环境转变为还原环境，营养盐以及可溶性Fe、Mn等污染物从沉积物释放到间隙水，进而扩散到上覆水中，造成底层水体污染物含量升高；（2）对沉积物样品做了锰吸附-解吸动力学实验，分析了不同因素对锰释放的交互影响，建立了3D响应曲面和2D的等高线图，得到促进Mndiss和Mn(III)释放的最优环境条件为：pH 6.0，DO浓度0.0 mg/L，温度30.0℃和DOC浓度10.8 mg/L，并基于CE－QUAL－W2模型构建了锰污染的生物地球化学模型；（3）在王圈水库应用构建的锰污染模型，利用实测资料进行了模型率定和验证，结果表明模型对于王圈水库夏季水温分层和锰污染现象都很好的模拟效果；（4）利用王圈水库锰污染模型，设置不同的模拟情景，分析了气温、水深、风速和风向对锰污染形成和扩散的影响，气温升高、水位升高、风速减小和逆水流方向的风向可以增加锰污染浓度，气温降低、水位降低、风速增大和顺水流方向的风向可以减小甚至消除锰污染浓度。研究成果为水库管理部门预警和防治锰污染提供了科学依据。