Combined14C and 13C Monitoring of in Situ Biodegradation of Petroleum Hydrocarbons
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- 作者：Mark E. Conrad ; Paul F. Daley ; Marc L. Fischer ; Bob B. Buchanan ; Terrance Leighton ; and Michaele Kashgarian
- 刊名：Environmental Science & Technology
- 出版年：1997
- 出版时间：May 1997
- 年：1997
- 卷：31
- 期：5
- 页码：1463 - 1469
- 全文大小：203K
- 年卷期：v.31,no.5(May 1997)
- ISSN：1520-5851
文摘
Measurements of the stable carbon isotope ratios(
13C)of microbial metabolic end products presents a promisingmethod for monitoring in situ bioremediation ofpetroleumhydrocarbons. Differences between the 13C valuesofhydrocarbons and indigenous carbon sources (e.g., plantmatter, soil carbonates) can be exploited to trace theorigins of metabolic end products. However, in zonesofmethanogenesis and/or where the 13C values ofendogenous plant matter overlap those of hydrocarbons,13Cmeasurements can produce ambiguous results. In suchcases, simultaneous measurement of the radiocarbon(14C)contents of metabolic end products can be used todetermine their sources. This method was applied at agasoline station spill site where hydrocarbons were theonlysource of14C-free carbon. Combined 13Cand14Cmeasurements of soil gas CO2 and dissolved inorganiccarbonin groundwater enabled quantification of carbon inputs.Furthermore, low14C contents of high13C CO2 were crucialin establishing that the soil gas CO2 was derivedfrommethanogenesis of hydrocarbons and not shell dissolution.In addition, low14C content coupled with a 16” dropinthe 13C values of CO2 across a semipermeablelayer beneaththe gas station building confirmed that microbialoxidationof methane was occurring within this zone.
13C)of microbial metabolic end products presents a promisingmethod for monitoring in situ bioremediation ofpetroleumhydrocarbons. Differences between the 13C valuesofhydrocarbons and indigenous carbon sources (e.g., plantmatter, soil carbonates) can be exploited to trace theorigins of metabolic end products. However, in zonesofmethanogenesis and/or where the 13C values ofendogenous plant matter overlap those of hydrocarbons,13Cmeasurements can produce ambiguous results. In suchcases, simultaneous measurement of the radiocarbon(14C)contents of metabolic end products can be used todetermine their sources. This method was applied at agasoline station spill site where hydrocarbons were theonlysource of14C-free carbon. Combined 13Cand14Cmeasurements of soil gas CO2 and dissolved inorganiccarbonin groundwater enabled quantification of carbon inputs.Furthermore, low14C contents of high13C CO2 were crucialin establishing that the soil gas CO2 was derivedfrommethanogenesis of hydrocarbons and not shell dissolution.In addition, low14C content coupled with a 16” dropinthe 13C values of CO2 across a semipermeablelayer beneaththe gas station building confirmed that microbialoxidationof methane was occurring within this zone.