Iwanyshyn M, Ryan M C, Chu A
Department of Civil Engineering, University of Calgary, 2500 University Drive NW Calgary, Alberta, Canada T2N 1N4.
Sci Total Environ. 2008 Feb 1;390(1):205-14. doi: 10.1016/j.scitotenv.2007.09.038. Epub 2007 Oct 31.
Diurnal variations in physical and chemical concentrations, including nutrients, are observed in river ecosystems. Understanding these cycles and separating the effects of physical loading (from point and non-point sources) and biogeochemical processes are necessary for water management and the TMDL process. A chloride mass balance approach is used to separate the relative influences of physical loading and biogeochemical processes in the Bow River through Calgary, Canada, which has a significant influence on the river water chemistry. Sampling campaigns were conducted in December 2005, when minimal photosynthesis and respiration occur, and in July 2006, when river discharge is high and some photosynthesis and respiration activity is present. Samples in each campaign were collected at point source input and output along the river reach through the city every hour for a 24-hour period, allowing for time of travel. The two wastewater treatment facilities within the city contributed the majority of physical mass loading to the river, with temporal variations in effluent discharge, chloride, and nutrient concentrations. Wastewater effluent chloride to nutrient (as well as other parameter relationships) concentrations also varied diurnally. An hourly chloride mass balance was achieved, within 0.5% (average, S.D.=4.4) for December and 7.7% (average, S.D.=4.2) for July, between estimated cumulative sum values from all inputs and measured values at the river output downgradient of the city, allowing for the investigation of other parameter conservativeness. Some slight diurnal variations associated with photosynthesis and respiration were observed even with limited productivity in the river. Nitrate mass fluxes appeared to be most strongly influenced by photosynthesis and respiration processes, with phosphate being less influenced. Ammonia mass fluxes appeared to be most strongly influenced by wastewater effluent loading. Physical loading can mask or enhance biogeochemical diurnal fluctuations, creating errors in river process interpretations. Chloride was a useful tracer in the mass balance to distinguish between and assist in separating physical loading and biogeochemical processes in the river.
在河流生态系统中，可观测到包括营养物质在内的物理和化学物质浓度的日变化。了解这些循环并区分物理负荷（来自点源和非点源）和生物地球化学过程的影响，对于水资源管理和总最大日负荷（TMDL）过程而言是必要的。采用氯化物质量平衡方法来区分流经加拿大卡尔加里的弓河（Bow River）中物理负荷和生物地球化学过程的相对影响，这对河水化学性质有重大影响。在2005年12月（此时光合作用和呼吸作用最少）以及2006年7月（此时河流流量大且存在一些光合作用和呼吸作用活动）开展了采样活动。每次采样活动中，在24小时内每小时沿着流经城市的河段在点源输入和输出处采集样本，以考虑水流时间。城市内的两个废水处理设施对河流的物理质量负荷贡献最大，其废水排放、氯化物和营养物质浓度存在时间变化。废水排放中的氯化物与营养物质（以及其他参数关系）浓度也呈现日变化。实现了每小时的氯化物质量平衡，12月时在所有输入的估计累积总和值与城市下游河流输出处的测量值之间的偏差在0.5%以内（平均值，标准差 = 4.4），7月时为7.7%（平均值，标准差 = 4.2），从而能够研究其他参数的守恒性。即使河流生产力有限，也观察到了一些与光合作用和呼吸作用相关的轻微日变化。硝酸盐质量通量似乎受光合作用和呼吸作用过程影响最大，而磷酸盐受影响较小。氨质量通量似乎受废水排放负荷影响最大。物理负荷可能掩盖或增强生物地球化学的日波动，在河流过程解释中产生误差。氯化物是质量平衡中一种有用的示踪剂，可用于区分并协助分离河流中的物理负荷和生物地球化学过程。
