Preliminary assessment of the occurrence and possible sources of MTBE in groundwater in the United States, 1993-1994
Preliminary assessment of the occurrence and possible sources of MTBE in groundwater in the United States, 1993-1994
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DOI：
10.1021/es9507170
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
P. Squillace;J. S. Zogorski;W. Wilber;C. V. Price
中科院分区：
文献类型：
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作者：
P. Squillace;J. S. Zogorski;W. Wilber;C. V. Price
1990年的《清洁空气法修正案》要求在一些大都市地区使用的汽油中添加燃料含氧物，以降低大气中一氧化碳或臭氧的浓度。甲基叔丁基醚（MTBE）是最常用的燃料氧合物，是一种较新的汽油添加剂。然而，在分析的60种挥发性有机化学物质中，MTBE是1993-1994年期间作为美国地质调查局国家水质评估计划的一部分收集的城市地区浅层地下水样本中第二常检测到的化学物质。样本采集自市区5口饮用水井、12口泉水和193口监测井。饮用水井中未检测到MTBE。在0.2 μg/L的报告水平下，与农业地区的浅层地下水（在21个地区取样的549口井中取样的1.3%）或主要含水层的深层地下水（在9个地区取样的412口井中取样的1.0%）相比，城市地区的浅层地下水中检测到MTBE的频率最高（在8个地区取样的210口井和泉水中检测到27%）。在城市地区取样的浅水井中，只有3%的MTBE浓度超过20 μg/L，这是美国环境保护署饮用水健康咨询草案的估计下限。由于MTBE在地下水中具有持久性和流动性，它可以随着时间的推移从浅层含水层移动到较深的含水层。在城市浅层地下水中，一般没有发现甲基叔丁基醚与苯、甲苯、乙苯或二甲苯（BTEX）化合物，这些化合物通常与汽油泄漏有关。这种分离导致了MTBE来源的不确定性。地下水中甲基叔丁基醚的可能来源包括点源，如泄漏的储罐，以及非点源，如降水和雨水径流的补给。
The 1990 Clean Air Act Amendments require fuel oxygenates to be added to gasoline used in some metropolitan areas to reduce atmospheric concentrations of carbon monoxide or ozone. Methyl tert-butyl ether (MTBE) is the most commonly used fuel oxygenate and is a relatively new gasoline additive. Nevertheless, out of 60 volatile organic chemicals analyzed, MTBE was the second most frequently detected chemical in samples of shallow ambient groundwater from urban areas that were collected during 1993-1994 as part of the U.S. Geological Survey's National Water-Quality Assessment program. Samples were collected from five drinking water wells, 12 springs, and 193 monitoring wells in urban areas. No MTBE was detected in drinking water wells. At a reporting level of 0.2 μg/L, MTBE was detected most frequently in shallow groundwater from urban areas (27% of 210 wells and springs sampled in eight areas) as compared to shallow groundwater from agricultural areas (1.3% of 549 wells sampled in 21 areas) or deeper groundwater from major aquifers (1.0% of 412 wells sampled in nine areas). Only 3% of the shallow wells sampled in urban areas had concentrations of MTBE that exceed 20 μg/L, which is the estimated lower limit of the United States Environmental Protection Agency draft drinking water health advisory. Because MTBE is persistent and mobile in groundwater, it can move from shallow to deeper aquifers with time. In shallow urban groundwater, MTBE generally was not found with benzene, toluene, ethylbenzene, or xylene (BTEX) compounds, which commonly are associated with gasoline spills. This disassociation causes uncertainty as to the source of MTBE. Possible sources of MTBE in groundwater include point sources, such as leaking storage tanks, and non-point sources, such as recharge of precipitation and stormwater runoff.