Variations in the biodegradation potential of subsurface environments for organic contaminants

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6721570

Hickman, G T

The purpose of this research was to evaluate the rates, patterns, and pathways involved in the biodegradation of organic contaminants in subsurface environments. Subsurface material was obtained from ten sites in six geographical locations representing diverse environmental conditions. The overall goal was to gain a general understanding of biodegradative mechanisms rather than making site-specific measurements. The biodegradation rates of methanol, phenol, and t-butanol (TBA) were evaluated in static soil/water microcosms. Biodegradation assays were conducted under ambient anoxic conditions, and with the addition of potential electron acceptors (nitrate, nitrite, sulfate) or metabolic inhibitors (molybdate, BESA) to promote different pathways of anaerobic microbial metabolism (nitrate respiration/denitrification, sulfate reduction, or methanogenesis). In unamended systems, biodegradation rates varied considerably between sit. Methanol and phenol were degraded fairly readily. Rates generally ranged from 0.5 to 1.0 mgL{sup {minus}1}d{sup {minus}1} for 20 C incubation. Disappearance of methanol and phenol followed zero- to first-order kinetics and was usually immediate, requiring no acclimation period. TBA was relatively recalcitrant in subsurface soils, disappearing at a rate of 0.1-0.3 mgL{sup {minus}1}d{sup {minus}1} (20 C). No biodegradation was evident, relative to sterile controls, in certain soils. The pattern of TBA degradation was typically biphasic: a long lag period of slow, linear removal was followed by an abrupt increase in removal rate (albeit still slow), Biodegradation rates were positively correlated with bacterial density for 12 soil samples from 3 sites within a localized area at Blacksburg, Virginia. However, this relationship did not exist between soils from diverse locations.

• Research Organization: Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (USA)
• OSTI ID: 6721570
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALCOHOLS
ANOXIA
AROMATICS
BIODEGRADATION
BIOLOGICAL PATHWAYS
BUTANOLS
CHEMICAL REACTIONS
CLEANING
DECOMPOSITION
DECONTAMINATION
HYDROXY COMPOUNDS
METHANOL
MICROCOSMS
ORGANIC COMPOUNDS
PHENOL
PHENOLS
REMOVAL
SOILS
SUBSURFACE ENVIRONMENTS