Biodegradation of synthetic chelates in subsurface sediments from the southeast coastal plain

Journal Article · · Journal of Environmental Quality; (United States)

DOI:https://doi.org/10.2134/jeq1993.00472425002200010016x· OSTI ID:6503637

Bolton, H Jr; Li, S W; Workman, D J; Girvin, D C ^[1]

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1. Pacific Northwest Lab., Richland, WA (United States)

The codisposal of synthetic chelating agents [e.g., ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), and nitrilotriacetic acid (NTA)] and radionuclides has been implicated in increased radionuclide transport in the subsurface environment. Microbial transformations of chelates in the subsurface are currently unknown, but could influence chelate persistence and thus alter the transport of radionuclides. Surface soil and subsurface sediments from five formations (36- to 376-m depth) were collected near Allendale, SC. Aerobic mineralization of [sup 14]C-labeled EDTA, DTPA, and NTA occurred in select sediments indicating that subsurface microorganisms can degrade chelates, whereas chelates may be relatively stable in strata where limited mineralization occurred. The chelates were not mineralized more rapidly or to a greater extent in the surface soil than in the subsurface sediments. The relative order of chelate persistence was EDTA > DTPA > NTA, with the maximum amount mineralized during 115 d at 15, 26, and 43%, respectively. Maximum mineralization of all three chelates did not occur in the same sediment, indicating that different microbial populations were responsible for the degradation of each chelate. Mineralization of chelates was minimal under denitrifying conditions and was reduced when additional soluble C was added. There was no relationship between chelate mineralization and the adsorption of chelates to sediments or the aqueous speciation of the chelates. 47 refs., 4 figs., 3 tabs.

• DOE Contract Number: AC06-76RL01830
• OSTI ID: 6503637
• Journal Information: Journal of Environmental Quality; (United States), Journal Name: Journal of Environmental Quality; (United States) Vol. 22:1; ISSN JEVQAA; ISSN 0047-2425
• Country of Publication: United States
• Language: English

Related Subjects

053002 -- Nuclear Fuels-- Environmental Aspects-- Radioactive Effluents-- (1992-)
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
54 ENVIRONMENTAL SCIENCES
540230* -- Environment
Terrestrial-- Radioactive Materials Monitoring & Transport-- (1990-)
AMINO ACIDS
BIODEGRADATION
CARBOXYLIC ACIDS
CHELATES
CHELATING AGENTS
CHEMICAL REACTIONS
CHEMISTRY
COMPLEXES
DECOMPOSITION
DRUGS
DTPA
EDTA
ENVIRONMENTAL TRANSPORT
MASS TRANSFER
MICROORGANISMS
MINERALIZATION
NTA
ORGANIC ACIDS
ORGANIC COMPOUNDS
RADIONUCLIDE MIGRATION
RADIOPROTECTIVE SUBSTANCES
SEDIMENTS
SOIL CHEMISTRY
SOILS