Solid‐State Nitrogen‐15 Nuclear Magnetic Resonance Analysis of Biologically Reduced 2,4,6‐Trinitrotoluene in a Soil Slurry Remediation

• Published in: Journal of environmental quality Vol. 30; no. 2; pp. 403 - 410
• Main Authors: Knicker, Heike, Achtnich, Christof, Lenke, Hiltrud
• Format: Journal Article
• Language: English
• Published: Madison American Society of Agronomy, Crop Science Society of America, Soil Science Society 01.03.2001; Crop Science Society of America; American Society of Agronomy
• Subjects: Amines; Anaerobic digestion; Anaerobic treatment; Applied sciences; Bacteria, Aerobic; Bacteria, Anaerobic; Biodegradation of pollutants; Biological analysis; Biological and medical sciences; Biotechnology; Decontamination. Miscellaneous; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environment and pollution; Environmental Monitoring; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Magnetic Resonance Spectroscopy - methods; Metabolites; Nitrogen Isotopes - chemistry; NMR; Nuclear magnetic resonance; Pollution; Pollution, environment geology; Radioactivity; Refuse Disposal; Slurries; Soil and sediments pollution; Soil contamination; Soil Pollutants - analysis; Trinitrotoluene - analysis; Trinitrotoluene - metabolism; Europe; Germany; Anaerobiosis; Biodegradation; Nitro compound; Aerobiosis; Nitrogen 15; Metabolite; In situ; Immobilization; NMR spectrometry; Soil pollution; Decontamination; Environment impact; Aromatic compound; Explosives; Bioremediation; TNT; Carbon 14; Degradation product; Organic compounds
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2001.302403x

ABSTRACT Soil contaminated with 2,4,6‐trinitrotoluene (TNT) and spiked with [14C]‐ and [15N3]‐TNT was subjected to an anaerobic–aerobic soil slurry treatment and subsequently analyzed by radiocounting and solid‐state 15N nuclear magnetic resonance (NMR) spectroscopy. This treatment led to a complete disappearance of extractable radioactivity originating from TNT and almost all of the radioactivity was recovered in the insoluble soil fraction. As revealed by solid‐state 15N NMR, a major fraction of partially reduced metabolites of TNT was immobilized into the soil during the early stage of the anaerobic treatment, although some of the compounds (i.e., aminodinitrotoluenes and azoxy compounds) were extractable by methanol. Considerable 15N intensity was assigned to condensation products of TNT metabolites. A smaller signal indicated the formation of azoxy N. This signal and the signal for nitro groups were not observed at the end of the anaerobic phase, revealing further reduction and/or transformation of their corresponding compounds. An increase of the relative proportion of the condensation products occurred with increasing anaerobic incubation. Aerobic incubation resulted in a further decrease of aromatic amines, presumably due to oxidative transformations or their involvement in further condensation reactions. The results of the study demonstrate that the anaerobic–aerobic soil slurry treatment represents an efficient strategy for immobilizing reduced TNT in soils.