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MTBE concentrations in ground water in Pennsylvania

Water-Resources Investigations Report 2003-4201

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Abstract

The distribution, concentrations, and detection frequency of methyl tert-butyl-ether (MTBE), a gasoline additive used in reformulated gasoline to improve air quality, were characterized in Pennsylvania?s ground water. Two sources of MTBE in ground water, the atmosphere and storage-tank release sites, were examined. An analysis of atmospheric MTBE concentrations shows that MTBE detections (MTBE greater than or equal to 0.2 micrograms per liter) in ground water are more likely the result of storage-tank releases than atmospheric deposition. A comparison of 86 ground-water samples near storage-tank releases and 359 samples from ambient ground water (not thought to be affected by point-source releases of MTBE or BTEX compounds) shows that samples within about 0.5 mile downgradient of storagetank release sites have significantly greater MTBE detection frequency than ambient ground-water samples. Aquifer type, land use, and the use of Reformulated Gasoline (RFG) are associated with high rates of occurrence of MTBE in ground water in Pennsylvania. Ground-water samples from wells in crystalline-rock aquifers near storage- tank release sites have a significantly greater MTBE detection frequency (57 percent) compared to other aquifers. Samples from wells in urban areas have a significantly greater MTBE detection frequency compared to ambient samples in agricultural and forested areas. Samples from the RFG-use areas in the five southeastern counties of Pennsylvania have a significantly greater MTBE detection frequency than samples outside of the RFG-use area. MTBE detection frequency of samples near storage- tank release sites in the RFG-use area (45 percent) are significantly greater than ambient samples in the RFG-use area.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
MTBE concentrations in ground water in Pennsylvania
Series title:
Water-Resources Investigations Report
Series number:
2003-4201
Edition:
-
Year Published:
2003
Language:
ENGLISH
Description:
44 p., 12 figs., 2 app.