Abstract
Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a potential human carcinogen, and its contamination of subsurface environments is a significant threat to public health. This study investigated abiotic and biological degradation of RDX in contaminated aquifer material. Anoxic batch systems were started with and without pre-aeration of aquifer material to distinguish initial biological RDX reduction from abiotic RDX reduction. Aerating the sediment eliminated chemical reductants in the native aquifer sediment, primarily Fe(II) sorbed to mineral surfaces. RDX (50 μM) was completely reduced and transformed to ring cleavage products when excess concentrations (2. mM) of acetate or lactate were provided as the electron donor for aerated sediment. RDX was reduced concurrently with Fe(III) when acetate was provided, while RDX, Fe(III), and sulfate were reduced simultaneously with lactate amendment. Betaproteobacteria were the dominant microorganisms associated with RDX and Fe(III)/sulfate reduction. In particular, Rhodoferax spp. increased from 21% to 35% and from 28% to 60% after biostimulation by acetate and lactate, respectively. Rarefaction analyses demonstrated that microbial diversity decreased in electron-donor-amended systems with active RDX degradation. Although significant amounts of Fe(III) and/or sulfate were reduced after biostimulation, solid-phase reactive minerals such as magnetite or ferrous sulfides were not observed, suggesting that RDX reduction in the aquifer sediment is due to Fe(II) adsorbed to solid surfaces as a result of Fe(III)-reducing microbial activity. These results suggest that both biotic and abiotic processes play an important role in RDX reduction under in situ conditions.
| Original language | English |
|---|---|
| Pages (from-to) | 1223-1230 |
| Number of pages | 8 |
| Journal | Chemosphere |
| Volume | 84 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - 2011 Aug 1 |
| Externally published | Yes |
Fingerprint
Keywords
- Abiotic reduction
- Biodegradation
- Electron donor
- Iron reduction
- RDX
ASJC Scopus subject areas
- Environmental Engineering
- Environmental Chemistry
- Chemistry(all)
- Pollution
- Health, Toxicology and Mutagenesis
Cite this
Geochemical and microbiological processes contributing to the transformation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in contaminated aquifer material. / Kwon, Man Jae; O'Loughlin, Edward J.; Antonopoulos, Dionysios A.; Finneran, Kevin T.
In: Chemosphere, Vol. 84, No. 9, 01.08.2011, p. 1223-1230.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Geochemical and microbiological processes contributing to the transformation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in contaminated aquifer material
AU - Kwon, Man Jae
AU - O'Loughlin, Edward J.
AU - Antonopoulos, Dionysios A.
AU - Finneran, Kevin T.
PY - 2011/8/1
Y1 - 2011/8/1
N2 - Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a potential human carcinogen, and its contamination of subsurface environments is a significant threat to public health. This study investigated abiotic and biological degradation of RDX in contaminated aquifer material. Anoxic batch systems were started with and without pre-aeration of aquifer material to distinguish initial biological RDX reduction from abiotic RDX reduction. Aerating the sediment eliminated chemical reductants in the native aquifer sediment, primarily Fe(II) sorbed to mineral surfaces. RDX (50 μM) was completely reduced and transformed to ring cleavage products when excess concentrations (2. mM) of acetate or lactate were provided as the electron donor for aerated sediment. RDX was reduced concurrently with Fe(III) when acetate was provided, while RDX, Fe(III), and sulfate were reduced simultaneously with lactate amendment. Betaproteobacteria were the dominant microorganisms associated with RDX and Fe(III)/sulfate reduction. In particular, Rhodoferax spp. increased from 21% to 35% and from 28% to 60% after biostimulation by acetate and lactate, respectively. Rarefaction analyses demonstrated that microbial diversity decreased in electron-donor-amended systems with active RDX degradation. Although significant amounts of Fe(III) and/or sulfate were reduced after biostimulation, solid-phase reactive minerals such as magnetite or ferrous sulfides were not observed, suggesting that RDX reduction in the aquifer sediment is due to Fe(II) adsorbed to solid surfaces as a result of Fe(III)-reducing microbial activity. These results suggest that both biotic and abiotic processes play an important role in RDX reduction under in situ conditions.
AB - Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a potential human carcinogen, and its contamination of subsurface environments is a significant threat to public health. This study investigated abiotic and biological degradation of RDX in contaminated aquifer material. Anoxic batch systems were started with and without pre-aeration of aquifer material to distinguish initial biological RDX reduction from abiotic RDX reduction. Aerating the sediment eliminated chemical reductants in the native aquifer sediment, primarily Fe(II) sorbed to mineral surfaces. RDX (50 μM) was completely reduced and transformed to ring cleavage products when excess concentrations (2. mM) of acetate or lactate were provided as the electron donor for aerated sediment. RDX was reduced concurrently with Fe(III) when acetate was provided, while RDX, Fe(III), and sulfate were reduced simultaneously with lactate amendment. Betaproteobacteria were the dominant microorganisms associated with RDX and Fe(III)/sulfate reduction. In particular, Rhodoferax spp. increased from 21% to 35% and from 28% to 60% after biostimulation by acetate and lactate, respectively. Rarefaction analyses demonstrated that microbial diversity decreased in electron-donor-amended systems with active RDX degradation. Although significant amounts of Fe(III) and/or sulfate were reduced after biostimulation, solid-phase reactive minerals such as magnetite or ferrous sulfides were not observed, suggesting that RDX reduction in the aquifer sediment is due to Fe(II) adsorbed to solid surfaces as a result of Fe(III)-reducing microbial activity. These results suggest that both biotic and abiotic processes play an important role in RDX reduction under in situ conditions.
KW - Abiotic reduction
KW - Biodegradation
KW - Electron donor
KW - Iron reduction
KW - RDX
UR - http://www.scopus.com/inward/record.url?scp=79960836676&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79960836676&partnerID=8YFLogxK
U2 - 10.1016/j.chemosphere.2011.05.027
DO - 10.1016/j.chemosphere.2011.05.027
M3 - Article
C2 - 21664641
AN - SCOPUS:79960836676
VL - 84
SP - 1223
EP - 1230
JO - Chemosphere
JF - Chemosphere
SN - 0045-6535
IS - 9
ER -