Effects of road salts on groundwater and surface water dynamics of sodium and chloride in an urban restored stream
Effects of road salts on groundwater and surface water dynamics of sodium and chloride in an urban restored stream
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DOI：
10.1007/s10533-014-9968-z
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发表时间：
2014-10-01
期刊：
影响因子：
4
通讯作者：
Faulkner, Barton R.
中科院分区：
文献类型：
--
作者：
Cooper, Curtis A.;Mayer, Paul M.;Faulkner, Barton R.
道路盐分是城市分水岭日益受到关注的环境问题。我们研究了美国马里兰州城市溪流Minebank Run(MBR)的地下水(GW)和地表水(SW)中Na+和Cl-的动态变化。我们观察到在这条恢复的溪流中盐度有上升的趋势。目前的基流盐度没有超过水质建议，但快速的“第一次冲刷”风暴流量大约是海水的三分之一。上游和下游研究范围的比较表明，一条主要的州际公路是主要的道路盐源。一条繁忙的道路与MBR的大部分平行，是GW浓度的另一个来源，特别是下游右岸。一项基流天气调查确定了盐度增加的区域。下游测压井的盐分浓度增加，有证据表明Na+正在交换土壤中的钙和镁。西南盐浓度一般高于GW浓度。MBR全年的盐度水平一直保持在MBR，并高于拜纳姆河段的本底水平，拜纳姆河段是附近的一条参考溪流，没有被一条主要公路一分为二，这表明GW是积累道路盐分的长期水库。慢性盐度水平可能高到足以破坏植被，盐度峰值可能会影响其他生物群。有益的用途和绿色基础设施投资可能面临盐分导致的退化的风险。因此，道路盐可能是一种环境风险，可能会影响水生生物群，并限制昂贵的资源管理和恢复工作的有效性。
Road salts are a growing environmental concern in urban watersheds. We examined groundwater (GW) and surface water (SW) dynamics of Na+ and Cl- in Minebank Run (MBR), an urban stream in Maryland, USA. We observed an increasing salinity trend in this restored stream. Current baseflow salinity does not exceed water quality recommendations, but rapid "first flush" storm flow was approximately one-third that of seawater. Comparisons between the upstream and downstream study reaches suggest that a major interstate highway is the primary road salt source. A heavily used road parallels most of MBR and was an additional source to GW concentrations, especially the downstream right bank. A baseflow synoptic survey identified zones of increased salinity. Downstream piezometer wells exhibited increases in salt concentrations and there was evidence that Na+ is exchanging Ca2+ and Mg2+ on soils. SW salt concentrations were generally elevated above GW concentrations. Salinity levels persisted at MBR throughout the year and were above background levels at Bynum Run, a nearby reference stream not bisected by a major highway, suggesting that GW is a long-term reservoir for accumulating road salts. Chronic salinity levels may be high enough to damage vegetation and salinity peaks could impact other biota. Beneficial uses and green infrastructure investments may be at risk from salinity driven degradation. Therefore, road salt may represent an environmental risk that could affect aquatic biota and limit the effectiveness of costly resource management and restoration efforts.