Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU), P.O. Box 7050, 750 07 Uppsala, Sweden.
Sci Total Environ. 2012 Aug 15;432:1-11. doi: 10.1016/j.scitotenv.2012.05.071. Epub 2012 Jun 15.
Surface waters are the main source of drinking water in many regions. Increasing organic carbon concentrations are a cause for concern in Nordic countries since both dissolved and particulate organic carbon can transport contaminants and adversely affect drinking water treatment processes. We present a long-term study of dynamics of total (particulate and dissolved) organic carbon (TOC) concentrations in the River Fyris. This river supplies drinking water to approximately 200000 people in Uppsala, Sweden. The River Fyris is a main tributary to Lake Mälaren, which supplies drinking water to approximately 2 million people in the greater Stockholm area. Utilities responsible for drinking water supply in both Uppsala and Stockholm have expressed concerns about possible increases in TOC. We evaluate organic carbon dynamics within the Fyris catchment by calculating areal mass exports using observed TOC concentrations and modeled flows and by modeling dissolved organic carbon (as a proxy for TOC) using the dynamic, process based INCA-C model. Exports of TOC from the catchment ranged from 0.8 to 5.8 g m(-2) year(-1) in the period 1995-2010. The variation in annual exports was related to climatic variability which influenced seasonality and amount of runoff. Exports and discharge uncoupled at the end of 2008. A dramatic increase in TOC concentrations was observed in 2009, which gradually declined in 2010-2011. INCA-C successfully reproduced the intra- and inter-annual variation in concentrations during 1996-2008 and 2010-2011 but failed to capture the anomalous increase in 2009. We evaluated a number of hypotheses to explain the anomaly in 2009 TOC values, ultimately none proved satisfactory. We draw two main conclusions: there is at least one unknown or unmeasured process controlling or influencing surface water TOC and INCA-C can be used as part of the decision-making process for current and future use of rivers for drinking water supply.
地表水体是许多地区饮用水的主要来源。在北欧国家，有机碳浓度的增加令人担忧，因为溶解态和颗粒态有机碳都可能携带污染物，并对饮用水处理过程产生不利影响。我们介绍了对菲里斯河总（颗粒态和溶解态）有机碳（TOC）浓度动态的长期研究。这条河为瑞典乌普萨拉的大约 20 万人提供饮用水。菲里斯河是梅拉伦湖的主要支流，为斯德哥尔摩大都市区的大约 200 万人提供饮用水。负责乌普萨拉和斯德哥尔摩饮用水供应的公用事业公司对 TOC 可能增加表示担忧。我们通过使用观测到的 TOC 浓度和模拟流量计算面积质量出口，以及通过使用动态、基于过程的 INCA-C 模型模拟溶解有机碳（作为 TOC 的替代品）来评估菲里斯流域的有机碳动态。在 1995-2010 年期间，TOC 从流域的输出量范围为 0.8 至 5.8 g m(-2) 年(-1)。年输出量的变化与影响季节性和径流量的气候变异性有关。2008 年底，出口量和排放量脱钩。2009 年观察到 TOC 浓度急剧增加，2010-2011 年逐渐下降。INCA-C 成功地复制了 1996-2008 年和 2010-2011 年期间的浓度年内和年际变化，但未能捕捉到 2009 年的异常增加。我们评估了一些假设来解释 2009 年 TOC 值的异常，最终没有一个证明是令人满意的。我们得出两个主要结论：至少有一个未知或未测量的过程控制或影响地表水 TOC，并且 INCA-C 可以用作当前和未来用于饮用水供应的河流决策过程的一部分。
