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Dual Biomarkers of Anaerobic Hydrocarbon Degradation in Historically Contaminated Groundwater

Authors :
Diane. L. Saber
Xiangyang Zhu
Lily Y. Young
Amita. R. Oka
Craig D. Phelps
Source :
Environmental Science & Technology. 45:3407-3414
Publication Year :
2011
Publisher :
American Chemical Society (ACS), 2011.

Abstract

This study reports that ongoing in situ anaerobic hydrocarbon biodegradation at a manufactured gas plant impacted site is occurring, 9 years after the initial investigation. Groundwater samples from the site monitoring wells (MW) were analyzed for biomarkers by GC-MS, end-point PCR, and quantitative PCR (qPCR). Metabolic biomarkers included specific intermediates of anaerobic naphthalene and/or 2-methylnaphthalene degradation: 2-naphthoic acid (2-NA); 5,6,7,8-tetrahydro-2-NA (TH-2-NA); hexahydro-2-NA (HH-2-NA); and carboxylated-2-methylnaphthalene (MNA). The analogues of gene bssA, encoding alpha subunit of enzyme benzylsuccinate synthase, were used as a genetic biomarker. Results indicate 1-2 orders of magnitude higher abundance of total bacteria in the impacted wells than in the unimpacted wells. End-point PCR analysis of bssA gene, with degenerate primers, indicated the presence of hydrocarbon degrading bacteria within the plume. In qPCR analysis, using primers based on toluene-degrading denitrifying or sulfate-reducing/methanogenic bacteria, bssA genes were detected only in MW-24, located downstream from the source. Metabolic biomarkers were detected in multiple wells. The highest abundance of 2-NA (6.7 μg/L), TH-2-NA (2.6 μg/L), HH-2-NA, and MNA was also detected in MW-24. The distribution of two independent biomarkers indicates that the site is enriched for anaerobic hydrocarbon biodegradation and provides strong evidence in support of natural attenuation.

Details

ISSN :
15205851 and 0013936X
Volume :
45
Database :
OpenAIRE
Journal :
Environmental Science & Technology
Accession number :
edsair.doi.dedup.....0a7d52dcc1dd7067ab9cb3ff21badda6
Full Text :
https://doi.org/10.1021/es103859t