Concentrations and Stable Isotope Values of BTEX in Gasoline-Contaminated Groundwater
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- 作者：Cheryl A. Kelley ; Beth Trust Hammer ; and Richard B. Coffin
- 刊名：Environmental Science & Technology
- 出版年：1997
- 出版时间：September 1997
- 年：1997
- 卷：31
- 期：9
- 页码：2469 - 2472
- 全文大小：240K
- 年卷期：v.31,no.9(September 1997)
- ISSN：1520-5851
文摘
This work was undertaken to investigate the usefulnessof stable carbon isotopic analysis as a monitoring toolforcontaminant remediation. Concentrations and 
13Cvaluesof BTEX (benzene, toluene, ethylbenzene, and xylenes)were measured at a gasoline-contaminated site in southernCalifornia. The BTEX data were determined using apurge-and-trap connected to a gas chromatograph/ion trap massspectrometer and to an isotope ratio mass spectrometersystem. Concentrations ranged from below detection(<0.5ppb 
0.05 
M C) to about 120 ppm (10 000 M C)totalBTEX, with toluene generally having the highestconcentrations. For BTEX compounds at monitoringwellsaveraged across all sampling dates, 13C valuesrangedfrom -23.8 to -26.6” (benzene), -22.9 to -25.2”(toluene),from -23.0 to -25.3” (p&m-xylenes), and from -22.4to-25.0” (o-xylene). The data strongly suggest twosources of contamination: one with lighter(12C-enriched)13C values emanating from the area nearmonitoringwells 1 and 2, and the other containing higher MTBEconcentrations, an additive of unleaded gasoline, withheavier(13C-enriched) 13C values coming from thevicinity ofmonitoring wells 8 and 9. The isotope data suggestthatthe leaded and unleaded gasoline at this site are isotopically distinct.
13Cvaluesof BTEX (benzene, toluene, ethylbenzene, and xylenes)were measured at a gasoline-contaminated site in southernCalifornia. The BTEX data were determined using apurge-and-trap connected to a gas chromatograph/ion trap massspectrometer and to an isotope ratio mass spectrometersystem. Concentrations ranged from below detection(<0.5ppb 0.05 M C) to about 120 ppm (10 000 M C)totalBTEX, with toluene generally having the highestconcentrations. For BTEX compounds at monitoringwellsaveraged across all sampling dates, 13C valuesrangedfrom -23.8 to -26.6” (benzene), -22.9 to -25.2”(toluene),from -23.0 to -25.3” (p&m-xylenes), and from -22.4to-25.0” (o-xylene). The data strongly suggest twosources of contamination: one with lighter(12C-enriched)13C values emanating from the area nearmonitoringwells 1 and 2, and the other containing higher MTBEconcentrations, an additive of unleaded gasoline, withheavier(13C-enriched) 13C values coming from thevicinity ofmonitoring wells 8 and 9. The isotope data suggestthatthe leaded and unleaded gasoline at this site are isotopically distinct.