(Bio)transformation of 2,4-dinitroanisole (DNAN) in soils

JOURNAL OF HAZARDOUS MATERIALS

卷:304

Article

Olivares, Christopher I.¹  Abrell, Leif^2,3  Khatiwada, Raju²  Chorover, Jon²  Sierra-Alvarez, Reyes¹  Field, Jim A.¹ 

[1] Univ Arizona, Dept Chem & Environm Engn, Tucson, AZ 85721 USA

[2] Univ Arizona, Dept Soil Water & Environm Sci, Tucson, AZ 85721 USA

[3] Univ Arizona, Dept Chem & Biochem, Tucson, AZ 85721 USA

关键词: 2,4-Dinitroanisole;    Biodegradation;    Insensitive munitions;    Soil;    Nitroaromatics;   

DOI  :  10.1016/j.jhazmat.2015.10.059

来源: Elsevier

【 摘 要 】

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. H-2 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. (C) 2015 Elsevier B.V. All rights reserved.

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