MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, PR China; Netherlands Institute of Ecology (NIOO-KNAW), Department of Aquatic Ecology, PO Box 50, 6700 AB Wageningen, The Netherlands.
MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, PR China.
Environ Pollut. 2018 Jun;237:339-347. doi: 10.1016/j.envpol.2018.02.026. Epub 2018 Mar 1.
Freshwater shallow lake ecosystems provide valuable ecological services to human beings. However, these systems are subject to severe contamination from anthropogenic sources. Per- and polyfluoroalkyl substances (PFASs), including perfluorooctanoic acid (PFOA) and perfluorooctane sulphonate (PFOS), are among the contaminants that have received substantial attention, primarily due to abundant applications, environment persistence, and potential threats to ecological and human health. Understanding the environmental behavior of these contaminants in shallow freshwater lake environments using a modeling approach is therefore critical. Here, we characterize the fate, transport and transformation of both PFOA and PFOS in the fifth largest freshwater lake in China (Chaohu) during a two-year period (2013-2015) using a fugacity-based multimedia fate model. A reasonable agreement between the measured and modeled concentrations in various compartments confirms the model's reliability. The model successfully quantifies the environmental processes and identifies the major sources and input pathways of PFOA and PFOS to the Chaohu water body. Sensitivity analysis reveals the critical role of nonlinear Freundlich sorption, which contributes to a variable fraction of the model true uncertainty in different compartments (8.1%-93.6%). Through additional model scenario analyses, we further elucidate the importance of nonlinear Freundlich sorption that is essential for the reliable model performance. We also reveal the distinct composition of emission sources for the two contaminants, as the major sources are indirect soil volatilization and direct release from human activities for PFOA and PFOS, respectively. The present study is expected to provide implications for local management of PFASs pollution in Lake Chaohu and to contribute to developing a general model framework for the evaluation of PFASs in shallow lakes.
淡水浅水湖泊生态系统为人类提供了有价值的生态服务。然而，这些系统受到人为来源的严重污染。全氟和多氟烷基物质（PFAS），包括全氟辛酸（PFOA）和全氟辛烷磺酸（PFOS），是受到广泛关注的污染物之一，主要是因为其大量应用、环境持久性以及对生态和人类健康的潜在威胁。因此，使用建模方法了解这些污染物在浅水淡水湖泊环境中的环境行为至关重要。在这里，我们使用基于逸度的多介质命运模型，描述了 2013 年至 2015 年期间中国第五大淡水湖（巢湖）中 PFOA 和 PFOS 的归宿、迁移和转化。各种隔室中测量浓度与模拟浓度之间的良好一致性证实了模型的可靠性。该模型成功量化了环境过程，并确定了 PFOA 和 PFOS 进入巢湖水体的主要来源和输入途径。敏感性分析揭示了非线性 Freundlich 吸附的关键作用，它导致不同隔室中模型真实不确定性的可变部分（8.1%-93.6%）。通过额外的模型情景分析，我们进一步阐明了非线性 Freundlich 吸附的重要性，这对于可靠的模型性能是必不可少的。我们还揭示了这两种污染物排放源的明显组成，因为主要来源分别是间接土壤挥发和直接人类活动释放的 PFOA 和 PFOS。本研究有望为巢湖 PFAS 污染的当地管理提供启示，并为评价浅水湖泊中 PFAS 的一般模型框架做出贡献。
