Increase of urban lake salinity by road deicing salt
Increase of urban lake salinity by road deicing salt
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DOI：
10.1016/j.scitotenv.2008.07.037
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发表时间：
2008-11-15
影响因子：
9.8
通讯作者：
Stefan, Heinz G.
中科院分区：
文献类型：
--
作者：
Novotny, Eric V.;Murphy, Dan;Stefan, Heinz G.
在明尼苏达州的双城都市区（TCMA），每年有超过317，000吨的道路盐（NaCl）用于道路除冰。虽然道路盐的使用是为了提高驾驶安全性，但这种做法会影响环境水质。对TCMA的13个湖泊进行了46个月的研究，以确定它们是否以及如何对道路盐的季节性应用作出反应。这些湖泊中的钠和氯化物浓度分别比该区域其他非城市湖泊高10倍和25倍。湖泊中的季节性盐度/氯化物循环与道路盐的应用：高浓度在冬季和春季，特别是靠近湖底，其次是较低的浓度在夏季和秋季，由于洪水冲刷的湖泊降雨径流。各湖泊的季节性盐储存/冲洗率来自体积加权平均氯化物浓度时间序列。该比率为湖泊最低含盐量的9%至55%。在研究的一些湖泊中，盐浓度高到足以阻止春季周转，阻止氧气到达底栖沉积物。沉积物上方的浓度也足够高，以诱导对流混合的盐水进入沉积物孔隙水。对TCMA中38个湖泊的历史水质记录进行的区域分析显示，1984年至2005年湖泊盐度的增加与明尼苏达州购买的岩盐数量高度相关。在个别湖泊中的氯离子浓度呈正相关，在流域的不透水面的百分比和湖泊体积呈负相关。两者合计，结果表明，持续退化的城市湖泊的水质，由于在其流域中的NaCl的应用。(C)2008 Elsevier B.V.保留所有权利。
Over 317,000 tonnes of road salt (NaCl) are applied annually for road deicing in the Twin Cities Metropolitan Area (TCMA) of Minnesota. Although road salt is applied to increase driving safety, this practice influences environmental water quality. Thirteen lakes in the TCMA were studied over 46 months to determine if and how they respond to the seasonal applications of road salt. Sodium and chloride concentrations in these lakes were 10 and 25 times higher, respectively, than in other non-urban lakes in the region. Seasonal salinity/chloride cycles in the lakes were correlated with road salt applications: High concentrations in the winter and spring, especially near the bottom of the lakes, were followed by lower concentrations in the summer and fall due to flushing of the lakes by rainfall runoff. The seasonal salt storage/flushing rates for individual lakes were derived from volume-weighted average chloride concentration time series. The rate ranged from 9 to 55% of a lake's minimum salt content. In some of the lakes studied salt concentrations were high enough to stop spring turnover preventing oxygen from reaching the benthic sediments. Concentrations above the sediments were also high enough to induce convective mixing of the saline water into the sediment pore water. A regional analysis of historical water quality records of 38 lakes in the TCMA showed increases in lake salinity from 1984 to 2005 that were highly correlated with the amount of rock salt purchased by the State of Minnesota. Chloride concentrations in individual lakes were positively correlated with the percent of impervious surfaces in the watershed and inversely with lake volume. Taken together, the results show a continuing degradation of the water quality of urban lakes due to application of NaCl in their watersheds. (C) 2008 Elsevier B.V. All rights reserved.