Soil found in old shooting ranges and military wastewater lagoons is often contaminated with TNT explosives. In some cases, common composting methods that clean the soil leave small particles of potentially carcinogenic substances. The researchers found that by adding acetone which is the main component of nail polish remover to this composting method, they can safely dissolve large blocks of TNT and biodegrade TNT.
Researchers from the Department of Energy's Idaho National Engineering and Environmental Laboratory modified the standard compost formulation and successfully dissolved and degraded bulk TNT from INEEL soil. They also found that under improved conditions, the microbial population that degrades explosives lived happily. The report, written by INEEL microbiologists Corey Radtke, Richard M. Lehman and Francisco F. Roberto, will be published in this week's Quarterly Journal of Bioremediation.
At the end of this process, TNT is completely degraded and acetone evaporates. "The beauty of this method is that when the experiment is completed," said Radtke, a microbiologist at INEEL, "the treated soil can enter the INEEL landfill, and we don't have to worry about it anymore."
Part of the land where INEEL is located is the naval shooting range during World War II. Due to military activities, TNT particles ranging in size from 56 grams to less than one hundredth of a gram can contaminate about 1000 cubic yards of soil. Although TNT explosive itself is unlikely to cause explosion hazard, the Environmental Protection Agency of the United States listed TNT explosive as a possible human carcinogen in its Integrated Risk Information System. As part of its overall environmental mission, and in order to protect the health of its workers, INEEL is working hard to clean up the remaining problems of TNT.
However, soil contaminated by TNT is not unique to INEEL. According to the United States Environmental Protection Agency, the soil of more than 30 ammunition test areas in the United States is polluted by TNT. For example, a World War II naval shooting range on the Hawaiian island of Kahooravi is the site of the largest unexploded ordnance recovery project funded. Last November, Radtke and his colleagues went to Maui to attend a meeting, which made the management managers aware of their promising technology.
Although TNT is considered to be a carcinogenic compound, microorganisms usually found in soil will eat it with relish. That is, if the seasoning is composed of old sawdust, hay, mashed beets and fertilizer samples in the form of compost. It is an effective method to dig soil and compost from TNT. It also provides a safe alternative to burning contaminated soil to burn explosives.
Unfortunately, bulk TNT is not easily decomposed by microorganisms and therefore remains in the soil at the end of the composting period. Workers need to handle TNT explosives to make them more accessible to microorganisms.
