title: Dechlorinating microorganisms in a sedimentary rock matrix contaminated with a mixture of VOCs.
abstract: Microbiological characterizations of contaminant biodegradation in fractured sedimentary rock have primarily focused on the biomass suspended in groundwater samples and disregarded the biomass attached to fractures and in matrix pores. In fractured sedimentary rock, diffusion causes nearly all contaminant mass to reside in porous, low-permeability matrix. Microorganisms capable of contaminant degradation can grow in the matrix pores if the pores and pore throats are sufficiently large. In this study, the presence of dechlorinating microorganisms in rock matrices was investigated at a site where a fractured, flat-lying, sandstone-dolostone sequence has been contaminated with a mixture of chlorinated and aromatic hydrocarbons for over 40 years. The profile of organic contaminants as well as the distribution and characterization of the microbial community spatial variability was obtained through depth-discrete, high-frequency sampling along a 98-m continuous rock core. Dechlorinating microorganisms, such as Dehalococcoides and Dehalobacter, were detected in the rock matrices away from fracture surfaces, indicating that biodegradation within the rock matrix blocks should be considered as an important component of the system when evaluating the potential for natural attenuation or remediation at similar sedimentary rock sites.
authors.affiliation: School of Engineering, University of Guelph, 50 Stone Road East, Guelph, Ontario, N1G 2W1, Canada. glaucia.lima@utoronto.ca
authors.forename: Gláucia
authors.initials: G
authors.lastname: Lima
authors.forename: Beth
authors.initials: B
authors.lastname: Parker
authors.forename: Jessica
authors.initials: J
authors.lastname: Meyer
mesh_terms: D001419:Bacteria / Q000235:genetics*; D001483:Base Sequence; D001673:Biodegradation, Environmental; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D058645:Denaturing Gradient Gel Electrophoresis; D005798:Genes, Bacterial / Q000235:genetics; D019015:Geologic Sediments / Q000382:microbiology*; D054879:Halogenation; D008855:Microscopy, Electron, Scanning; D016133:Polymerase Chain Reaction; D016062:Porosity; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis*; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D055549:Volatile Organic Compounds