Abstract
The aerobic biodegradability of the high explosive CL-20 by activated sludge and the white rot fungus Phanerochaete chrysosporium has been investigated. Although activated sludge is not effective in degrading CL-20 directly, it can mineralize the alkaline hydrolysis products. Phanerochaete chrysosporium degrades CL-20 in the presence of supplementary carbon and nitrogen sources. Biodegradation studies were conducted using various nutrient media under diverse conditions. Variables included the CL-20 concentration; levels of carbon (as glycerol) and ammonium sulfate and yeast extract as sources of nitrogen. Cultures that received CL-20 at the time of inoculation transformed CL-20 completely under all nutrient conditions studied. When CL-20 was added to pre-grown cultures, degradation was limited. The extent of mineralization was monitored by the 14CO2 time evolution; up to 51% mineralization was achieved when the fungus was incubated with [14C]-CL-20. The kinetics of CL-20 biodegradation by Phanerochaete chrysosporium follows the logistic kinetic growth model.
Highlights
The high-energy polycyclic nitramine (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane), commonly known as CL-20, is a synthesized energetic compound [1]
Some minor CL-20 depletions observed in both the control and experimental vials may be attributed to abiotic transformations, most likely hydrolysis, since the pH of the reaction medium was in the alkaline range at the end of the incubation period
It can be concluded that alkaline hydrolysis coupled with aerobic microbial treatment is a technically feasible option for the removal of CL-20 and its by-products from contaminated waste streams and groundwater
Summary
The high-energy polycyclic nitramine (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane), commonly known as CL-20, is a synthesized energetic compound [1]. The basic structure of CL-20 consists of a rigid isowurtzitane cage with a nitro group attached to each of the six bridging nitrogen atoms. As shown, it resembles the conventional monocyclic explosives cyclotetramethylenetetranitramine (HMX) and cyclotrimethylenetrinitramine (RDX). It is likely that CL-20 may present similar environmental challenges to HMX and RDX [4]. Preliminary studies have reported that CL-20 exhibits similar ecotoxicological potency as HMX and RDX [5]. CL-20 is not toxic to marine bacteria Vibrio fischeri, freshwater green algae Selenastrum capricornutum, terrestrial higher plants and indigenous soil microorganisms [5]. It is highly toxic to the soil invertebrates such as the earthworm
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: International Journal of Environmental Research and Public Health
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
