Water quality following extensive beetle-induced tree mortality: Interplay of aromatic carbon loading, disinfection byproducts, and hydrologic drivers
Water quality following extensive beetle-induced tree mortality: Interplay of aromatic carbon loading, disinfection byproducts, and hydrologic drivers
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DOI：
10.1016/j.scitotenv.2016.06.106
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发表时间：
2016-12-01
影响因子：
9.8
通讯作者：
Sharp, Jonathan O.
中科院分区：
文献类型：
--
作者：
Brouillard, Brent M.;Dickenson, Eric R. V.;Sharp, Jonathan O.
最近北美西部的树皮甲虫流行病可能会影响水质，因为有机碳释放量增加和与广泛的树木枯死相关的水文变化。对2004年至2014年的季度市政监测数据进行分析，并根据甲虫影响的程度对落基山脉的六个水处理设施进行离散化，结果显示，在高浓度范围内，总有机碳（TOC）和总三卤甲烷（TTHM）产量呈显着增加趋势。（大于或类似于50%的面积虫害）受甲虫影响的流域，而在影响程度较低的流域没有发现或发现微不足道的趋势。令人担忧的是，在最近两年的分析（2013-14）中，高影响地点的TTHM浓度趋势超过了监管的最大污染物水平。为了评估季节性差异，探索水质和水文过程的相互作用，并消除与市政报告相关的变化，这些处理设施的目标是更详细的地表水采样和表征。从高影响流域收集的地表水样品表现出显着更高的TOC，芳香签名，消毒副产品（DBP）的形成潜力比流域较低的侵扰水平。对地表水样品的光谱分析表明，这些升高的DBP前体水平是升高的TOC负荷和增加的芳香特性的函数。这种关联在高影响站点的降水和径流事件中得到了加强，支持了这样一种假设，即径流停止后几个月内，由于树木死亡而改变的水文流动路径会动员有机碳并提高DBP形成的潜力。这里发现的历史趋势可能低估了TTHM变化的全部程度，这是由于监测偏差，DBP前体的延长季节性释放增加了人类暴露的可能性。总的来说，我们的分析表明，虽然水质的影响继续上升近十年后，虫害，TOC动员和DBP前体的显着增加仅限于流域，经验丰富的树木死亡率。(C)© 2016 Elsevier B. V.版权所有。
The recent bark beetle epidemic across western North America may impact water quality as a result of elevated organic carbon release and hydrologic shifts associated with extensive tree dieback. Analysis of quarterly municipal monitoring data from 2004 to 2014 with discretization of six water treatment facilities in the Rocky Mountains by extent of beetle impact revealed a significant increasing trend in total organic carbon (TOC) and total trihalomethane (TTHM) production within high (greater than or similar to 50% areal infestation) beetle-impacted watersheds while no or insignificant trends were found in watersheds with lower impact levels. Alarmingly, the TTHM concentration trend in the high impact sites exceeded regulatory maximum contaminant levels during the most recent two years of analysis (2013-14). To evaluate seasonal differences, explore the interplay of water quality and hydrologic processes, and eliminate variability associated with municipal reporting, these treatment facilities were targeted for more detailed surface water sampling and characterization. Surface water samples collected from high impact watersheds exhibited significantly higher TOC, aromatic signatures, and disinfection byproduct (DBP) formation potential than watersheds with lower infestation levels. Spectroscopic analyses of surface water samples indicated that these heightened DBP precursor levels are a function of both elevated TOC loading and increased aromatic character. This association was heightened during precipitation and runoff events in high impact sites, supporting the hypothesis that altered hydrologic flow paths resulting from tree mortality mobilize organic carbon and elevate DBP formation potential for several months after runoff ceases. The historical trends found here likely underestimate the full extent of TTHM shifts due to monitoring biases with the extended seasonal release of DBP precursors increasing the potential for human exposure. Collectively, our analysis suggests that while water quality impacts continue to rise nearly one decade after infestation, significant increases in TOC mobilization and DBP precursors are limited to watersheds that experience extensive tree mortality. (C) 2016 Elsevier B.V. All rights reserved.