Kaushal Sujay S, Reimer Jenna E, Mayer Paul M, Shatkay Ruth R, Maas Carly M, Nguyen William D, Boger Walter L, Yaculak Alexis M, Doody Thomas R, Pennino Michael J, Bailey Nathan W, Galella Joseph G, Weingrad Aaron, Collison Daniel C, Wood Kelsey L, Haq Shahan, Johnson Tamara A Newcomer, Duan Shuiwang, Belt Kenneth T
Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA.
US Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, Corvallis, Oregon, 97333, USA.
Freshw Sci. 2022 Sep 1;41(3):420-441. doi: 10.1086/721469.
We investigate impacts of Freshwater Salinization Syndrome (FSS) on mobilization of salts, nutrients, and metals in urban streams and stormwater BMPs by analyzing original data on concentrations and fluxes of salts, nutrients, and metals from 7 urban watersheds in the Mid-Atlantic U.S. and synthesizing literature data. We also explore future critical research needs through a survey of practitioners and scientists. Our original data show: (1) sharp pulses in concentrations of salt ions and metals in urban streams directly following both road salt events and stream restoration construction (.., similar to the way concentrations increase during other soil disturbance activities); (2) sharp declines in pH (acidification) in response to road salt applications due to mobilization of H from soil exchange sites by Na; (3) sharp increases in organic matter from microbial and algal sources (based on fluorescence spectroscopy) in response to road salt applications likely due to lysing cells and/or changes in solubility; (4) significant retention (~30-40%) of Na in stormwater BMP sediments and floodplains in response to salinization; (5) increased ion exchange and mobilization of diverse salt ions (Na, Ca, K, Mg), nutrients (N, P), and trace metals (Cu, Sr) from stormwater BMPs and restored streams in response to FSS; (6) downstream increasing loads of Cl, SO , Br, F, and I along flowpaths through urban streams, and P release from urban stormwater BMPs in response to salinization, and (7) a significant annual reduction (> 50%) in Na concentrations in an urban stream when road salt applications were dramatically reduced, which suggests potential for ecosystem recovery. We compared our original results to published metrics of contaminant retention and release across a broad range of stormwater management BMPs from North America and Europe. Overall, urban streams and stormwater management BMPs consistently retain Na and Cl but mobilize multiple contaminants based on salt types and salinity levels. Finally, we present our top 10 research questions regarding FSS impacts on urban streams and stormwater management BMPs. Reducing diverse 'chemical cocktails' of contaminants mobilized by freshwater salinization is now a priority for effectively and holistically restoring urban waters.
我们通过分析美国中大西洋地区7个城市流域盐类、养分和金属浓度及通量的原始数据，并综合文献数据，研究淡水盐碱化综合征（FSS）对城市溪流和雨水最佳管理措施（BMPs）中盐类、养分和金属迁移的影响。我们还通过对从业者和科学家的调查，探索未来关键的研究需求。我们的原始数据显示：（1）在道路撒盐事件和溪流修复建设之后，城市溪流中盐离子和金属浓度出现急剧脉冲（……，类似于其他土壤扰动活动期间浓度增加的方式）；（2）由于钠从土壤交换位点置换出氢离子，道路撒盐导致pH值急剧下降（酸化）；（3）道路撒盐后，微生物和藻类来源的有机物质（基于荧光光谱）急剧增加，可能是由于细胞裂解和/或溶解度变化；（4）盐碱化导致雨水BMP沉积物和洪泛区中钠的显著截留（约30 - 40%）；（5）FSS导致雨水BMP和恢复溪流中多种盐离子（钠、钙、钾、镁）、养分（氮、磷）和痕量金属（铜、锶）的离子交换和迁移增加；（6）沿城市溪流流动路径，下游的氯、硫酸根、溴、氟和碘负荷增加，以及盐碱化导致城市雨水BMP中磷的释放；（7）当道路撒盐量大幅减少时，城市溪流中钠浓度每年显著降低（> 50%），这表明生态系统有恢复的潜力。我们将我们的原始结果与北美和欧洲广泛的雨水管理BMPs中已发表的污染物截留和释放指标进行了比较。总体而言，城市溪流和雨水管理BMPs持续截留钠和氯，但根据盐类类型和盐度水平会迁移多种污染物。最后，我们提出了关于FSS对城市溪流和雨水管理BMPs影响的前10个研究问题。减少淡水盐碱化所迁移的各种污染物“化学混合物”，现在是有效和全面恢复城市水体的当务之急。
