title: Dual biomarkers of anaerobic hydrocarbon degradation in historically contaminated groundwater.
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.
authors: Department of Environmental Sciences, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey , New Brunswick, New Jersey 08901, United States.
authors: Amita R
authors: AR
authors: Oka
authors: Craig D
authors: CD
authors: Phelps
authors: Xiangyang
authors: X
authors: Zhu
authors: Diane L
authors: DL
authors: Saber
authors: L Y
authors: LY
authors: Young
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D015415:Biomarkers / Q000378:metabolism; D004784:Environmental Monitoring / Q000379:methods*; D005618:Fresh Water / Q000737:chemistry* / Q000382:microbiology; D005798:Genes, Bacterial / Q000235:genetics; D006838:Hydrocarbons / Q000032:analysis / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D006838:Hydrocarbons; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical