TY - JOUR
T1 - (Bio)transformation of 2,4-dinitroanisole (DNAN) in soils
AU - Olivares, Christopher I.
AU - Abrell, Leif
AU - Khatiwada, Raju
AU - Chorover, Jon
AU - Sierra-Alvarez, Reyes
AU - Field, Jim A.
N1 - Funding Information:
This study was supported by the Strategic Environmental Research and Development Program (SERDP) project ER-2221 and NSF CBET 1510698. Analyses performed at the Arizona Laboratory for Emerging Contaminants (ALEC) were supported by NSF CBET 0722579, AB Sciex, and additional funding from University of Arizona colleges. CIO was supported by the Mexican National Council for Science and Technology (CONACyT) and the NIEHS Superfund Research Program (P42 ES04940). We thank Dr. Katerina Donstova, Stefan Walston, and CH2 M Hill for the soils in this study and Dr. Mark J. Krzmarzick for intellectual input to this work.
Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2016/3/5
Y1 - 2016/3/5
N2 - Recent studies have begun to assess the environmental fate and toxicity of 2,4-dinitroanisole (DNAN), an insensitive munition compound of interest to defense agencies. Aerobic and anaerobic DNAN biotransformation in soils was evaluated in this study. Under aerobic conditions, there was little evidence of transformation; most observed removal was attributed to adsorption and subsequent slow chemical reactions. Under anaerobic conditions, DNAN was reductively (bio)transformed and the rate of the transformation was positively correlated with soil organic carbon (OC) up to a threshold of 2.07% OC. H2 addition enhanced the nitroreduction rate compared to endogenous treatments lacking H2. Heat-killed treatments provided rates similar to the endogenous treatment, suggesting that abiotic factors play a role in DNAN reduction. Ten (bio)transformation products were detected by high-resolution mass spectrometry. The proposed transformation pathway involves reduction of DNAN to aromatic amines, with putative reactive nitroso-intermediates coupling with the amines to form azo dimers. Secondary reactions include N-alkyl substitution, O-demethylation (sometimes followed by dehydroxylation), and removal of an N-containing group. Globally, our results suggest that the main reaction DNAN undergoes in anaerobic soils is nitroreduction to 2-methoxy-5-nitroaniline (MENA) and 2,4-diaminoanisole (DAAN), followed by anaerobic coupling reactions yielding azo-dimers. The dimers were subsequently subject to further (bio)transformations.
AB - Recent studies have begun to assess the environmental fate and toxicity of 2,4-dinitroanisole (DNAN), an insensitive munition compound of interest to defense agencies. Aerobic and anaerobic DNAN biotransformation in soils was evaluated in this study. Under aerobic conditions, there was little evidence of transformation; most observed removal was attributed to adsorption and subsequent slow chemical reactions. Under anaerobic conditions, DNAN was reductively (bio)transformed and the rate of the transformation was positively correlated with soil organic carbon (OC) up to a threshold of 2.07% OC. H2 addition enhanced the nitroreduction rate compared to endogenous treatments lacking H2. Heat-killed treatments provided rates similar to the endogenous treatment, suggesting that abiotic factors play a role in DNAN reduction. Ten (bio)transformation products were detected by high-resolution mass spectrometry. The proposed transformation pathway involves reduction of DNAN to aromatic amines, with putative reactive nitroso-intermediates coupling with the amines to form azo dimers. Secondary reactions include N-alkyl substitution, O-demethylation (sometimes followed by dehydroxylation), and removal of an N-containing group. Globally, our results suggest that the main reaction DNAN undergoes in anaerobic soils is nitroreduction to 2-methoxy-5-nitroaniline (MENA) and 2,4-diaminoanisole (DAAN), followed by anaerobic coupling reactions yielding azo-dimers. The dimers were subsequently subject to further (bio)transformations.
KW - 2,4-Dinitroanisole
KW - Biodegradation
KW - Insensitive munitions
KW - Nitroaromatics
KW - Soil
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U2 - 10.1016/j.jhazmat.2015.10.059
DO - 10.1016/j.jhazmat.2015.10.059
M3 - Article
C2 - 26551225
AN - SCOPUS:84946430357
SN - 0304-3894
VL - 304
SP - 214
EP - 221
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
ER -