C’mon In! The Water’s Threat-Free
Tracking the degradation of explosive materials in the water could make for safer seas. A team of researchers found that the power of the sun can go a long way in degrading explosives that could be in unexploded ordinance in seas, rivers and other bodies of water.
C’mon In! The Water’s Threat-Free
FORT BELVOIR, Va. – Tracking the degradation of explosive materials in the water could make for safer seas. A team of researchers at the U. S. Naval Academy, managed by DTRA CB/JSTO’s Dr. Brian Pate, found that the power of the sun can go a long way in degrading explosives that could be in unexploded ordinance in seas, rivers and other bodies of water.
A pair of articles appearing in the journal Marine Chemistry by author Dianne J. Luning Park described the characterization of the effect of various physicochemical variables, such as pH, temperature, nitrate concentration, salinity, and dissolved organic matter on the photolysis of explosive molecules and their simulants in environmental water sources. Photolysis products were characterized by chromatographic methods and mass spectroscopy, and degradation rate constants were determined.
In the article, “Influence of pH, temperature, salinity, and dissolved organic matter on the photolysis of 2,4-dinitrotoluene and 2,6-dinitrotoluene in seawater,” the researchers found the organic compounds 2,4- and 2,6-dinitrotoluene (2,4- and 2,6-DNT), precursors to the more well-known trinitrotoluene (TNT), were influenced by the wavelength of the light irradiating from the compound, and first-order DNT degradation rate constants were amplified with increasing salinity for both natural seawater and artificial seawater. Temperature, pH, and nitrate levels did change DNTs’ rate constants. Also, more dissolved organic matter (up to 10 mg/L) in ultrapure water, artificial seawater (salinity = 9), and natural seawater enhanced the photolysis of 2,6-DNT, while it only enhanced the photolysis of 2,4-DNT in the ultrapure and artificial seawater (salinity = 9). Products formed by 2,4-DNT photolysis in natural seawater were 2,4-dinitrobenzaldehyde, 2,4-dinitrobenzylnitrile, and 2-amino,4-nitrobenzoic acid. The photolysis of 2,6-DNT in natural seawater formed 2,6-dinitrobenzaldehyde, 2,6-dinitrobenzyl alcohol, and 2,6-dinitrobenzylnitrile. Another article in the same journal, “Photolysis of dinitrobenzyl alcohols, dinitrobenzaldehydes, and nitrobenzoic acids in seawater, estuary water, and pure water,” found similar results in photolytic transformation of the propellants.
Research results indicated these materials and their decomposition products might accumulate and potentially pose a long term hazard unless additional chemical or biological processes occurred to expedite the decomposition path and ultimately render them inert.
This DTRA CB/JSTO-funded research is part of the agency’s Service Academy Initiative, a program intended to support research and leadership excellence within the U.S. armed services.
If the program is successful, warfighters, especially those in water-borne vessels, will see better methods to detect and avoid unexploded ordinance, as well as possible protections against hazardous materials that might form when explosive materials break down.
Source: DVIDS.
