Biodegradation of nitro-explosives

2011

INTRODUCTION Production, storage and testing of explosives have resulted in a widespread environmental problem because these mutagenic, toxic, and persistent compounds have leached from soils and accumulated in the food chain (Rieger et al., 1995; Walker et al., 1992; Won et al., 1976). The contamination of the environment by explosives, especially by nitroaromatics (nitro aromatic compound – NAC), is a worldwide environmental problem since enormous amounts of these compounds were produced during World War I and II. Most contaminated sites are located at ammunition factories and other places where these compounds were handled. This involved open detonation and burning of explosives at army depots, evaluation facilities, artillery ranges, and ordnance disposal sites (Rodgers et al., 2001). Improper TNTcontaining solid/liquid waste disposal was generated during the production, burning detonation, and dismantlement of munitions, and this led to serious TNT contamination of soils and gr...

European Journal of Engineering Research and Science, 2018

Military training activities as well as manufacturing and decommissioning operations, lead to the generation of large quantities of explosive chemicals. Detonation and disposal of these explosive chemicals contaminate soil and ground water, thus posing a threat to living organisms and natural resources. The most commonly used explosives in artillery shells, bombs, grenades and other munitions are 2,4,6-Trinitrotoluene (TNT), Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). Due to their recalcitrant nature, toxicity and persistence in the environment, the study of their biodegradation and biotransformation is paramount. This paper reviews the chemistry, fate, degradation and transformation of these explosive chemicals in the natural environment. Emphasis is placed on TNT, RDX and HMX. This review will help scientists to adopt strategies and develop optimum biological treatment scheme for the in situ bioremediation of explosives-contaminated soil especially at firing/impact ranges.

Journal of Hazardous Materials, 2012

Explosives are synthesized globally mainly for military munitions. Nitrate esters, such as GTN and PETN, nitroaromatics like TNP and TNT and nitramines with RDX, HMX and CL20, are the main class of explosives used. Their use has resulted in severe contamination of environment and strategies are now being developed to clean these substances in an economical and eco-friendly manner. The incredible versatility inherited in microbes has rendered these explosives as a part of the biogeochemical cycle. Several microbes catalyze mineralization and/or nonspecific transformation of explosive waste either by aerobic or anaerobic processes. It is likely that ongoing genetic adaptation, with the recruitment of silent sequences into functional catabolic routes and evolution of substrate range by mutations in structural genes, will further enhance the catabolic potential of bacteria toward explosives and ultimately contribute to cleansing the environment of these toxic and recalcitrant chemicals. This review summarizes information on the biodegradation and biotransformation pathways of several important explosives. Isolation, characterization, utilization and manipulation of the major detoxifying enzymes and the molecular basis of degradation are also discussed. This may be useful in developing safer and economic microbiological methods for clean up of soil and water contaminated with such compounds. The necessity of further investigations concerning the microbial metabolism of these substances is also discussed.

Biotechnology Letters, 2020

Applied Microbiology and Biotechnology, 2006

Cyclic nitramine explosives are synthesized globally mainly as military munitions, and their use has resulted in environmental contamination. Several biodegradation pathways have been proposed, and these are based mainly on end-product characterization because many of the metabolic intermediates are hypothetical and unstable in water. Biodegradation mechanisms for cyclic nitramines include (a) formation of a nitramine free radical and loss of nitro functional groups, (b) reduction of nitro functional groups, (c) direct enzymatic cleavage, (d) α-hydroxylation, or (e) hydride ion transfer. Pathway intermediates spontaneously decompose in water producing nitrite, nitrous oxide, formaldehyde, or formic acid as common end-products. In vitro enzyme and functional gene expression studies have implicated a limited number of enzymes/genes involved in cyclic nitramine catabolism. Advances in molecular biology methods such as high-throughput DNA sequencing, microarray analysis, and nucleic acid sample preparation are providing access to biochemical and genetic information on cultivable and uncultivable microorganisms. This information can provide the knowledge base for rational engineering of bioremediation strategies, biosensor development, environmental monitoring, and green biosynthesis of explosives. This paper reviews recent developments on the biodegradation of cyclic nitramines and the potential of genomics to identify novel functional genes of explosive metabolism.

Molecules

Nitroaromatic and nitroamine compounds such as 2,4,6-trinitrotoluene (TNT) are teratogenic, cytotoxic, and may cause cellular mutations in humans, animals, plants, and microorganisms. Microbial-based bioremediation technologies have been shown to offer several advantages against the cellular toxicity of nitro-organic compounds. Thus, the current study was designed to evaluate the ability of Trichoderma viride to degrade nitrogenous explosives, such as TNT, by microbiological assay and Gas chromatography–mass spectrometry (GC–MS) analysis. In this study, T. viride fungus was shown to have the ability to decompose, and TNT explosives were used at doses of 50 and 100 ppm on the respective growth media as a nitrogenous source needed for normal growth. The GC/MS analysis confirmed the biodegradable efficiency of TNT, whereas the initial retention peak of the TNT compounds disappeared, and another two peaks appeared at the retention times of 9.31 and 13.14 min. Mass spectrum analysis iden...

Epidemiologia e Serviços de Saúde, 2024

Objetivo Descrever a completude vacinal em tempo oportuno nos primeiros 24 meses de vida no Brasil e os obstáculos para vacinação, testando-se associações com raça/cor da pele materna. Métodos Fez-se coleta de informações sobre os nascidos em 2017 e 2018, constantes no Inquérito Nacional de Cobertura Vacinal. Foram calculados prevalência e intervalos de confiança de 95% de obstáculos à vacinação e completude vacinal em tempo oportuno aos 5 meses, primeiro e segundo ano, segundo raça/cor da pele materna. Empregou-se regressão logística para análise de associações. Resultados Analisaram-se dados de 37.801 crianças. Do total, 7,2% (IC95% 6,3;8,2) dos responsáveis enfrentaram dificuldades para levar seus filhos para vacinação e 23,4% (IC95% 21,7;25,1) das crianças não foram vacinadas, mesmo sendo levadas. Essas proporções foram 75% (IC95% 1,25;2,45) e 97% (IC95% 1,57;2,48) mais elevadas, respectivamente, entre pretas; e 49,9% (IC95% 47,8;51,9) e 61,1% (IC95% 59,2;63,0) das crianças tiveram atraso em alguma vacina até os 5 meses e o primeiro ano, respectivamente. Tais valores foram maiores entre pardas/pretas. Conclusão Há desigualdades raciais nos obstáculos enfrentados e na vacinação no Brasil.

ZEIT(EN) DES UMBRUCHS Akten des 17. Internationalen Kolloquiums zum provinzialrömischen Kunstschaffen Wien – Carnuntum, 16.–21. Mai 2022, 2024

Further considerations about the statuary found in the context of the late antique residences in Stobi are made, particularly those from the so-called Houses of Parthenius and Polycharmos. These statues belong to different periods than the context of their fnding, ranging in date from the Hellenistic period up to Roman Imperial times. Some of them might have been locally made, but most of them are imports exhibiting high artistic qualities, all of them serving new purposes as collectables. This study focuses mostly on their possible original position and their reuse in secondary contexts before their fnal deposit. It also argues whether they are a legacy from the local heritage or imported; their style, dating and provenience are considered, introducing new perspectives, all with the purpose of recognizing the late antique habit of preserving Roman statuary and worship among the local aristocracy.