Modeling suggests chemical weapons can be safely buried in landfills

Published 29 June 2006

It is one thing to protect against and cope with a chemical attack by terrorists; but what about disposing of the chemically tainted debris in the wake of the attack? Incinerators in the United States will probably be overwhelmed; a new computer modeling study suggests that such debris can be safely disposed of in landfills

Debris contaminated by a chemical weapon attack could be safely disposed of in landfill sites alongside household waste, according to a recently conducted computer simulations. The simulations were carried out by a team of U.S. and Danish environmental engineers, and they suggest that toxic compounds would react with water and organic compounds in the landfill, in the process preventing their escape into the environment. The researchers used computer models to test what would happen to a variety of dangerous compounds which might appear in debris contaminated by chemical attack. Among the thirteen toxic compounds they considered were the nerve gases sarin and VX and the blistering agent mustard gas.

The results indicate burial in landfill will not result in a massive release of toxic chemicals,” says Morton Barlaz at North Carolina State University, lead author of the study. “Our work can now be used by scientists who specialise in health effects to confirm that landfill disposal is acceptable.”

According to the model, many of the toxic compounds would degrade entirely within a year through reactions with water. Most of the remaining compounds would disappear after five years through reactions with organic compounds or degradation by microorganisms. The only exception was the toxic gas phosgene. The modeling also showed chemical agents would not escape as gas or seep into groundwater, says Barlaz.

Chris Cheeseman, an environmental engineer at Imperial College London, says that landfills have not been investigated as a means of disposing of chemical warfare contamination before. “Materials like these would normally be disposed of by incineration,” he says. Incineration may be suitable for destroying old weapons stock, but the large amount of contaminated debris which is likely to be created by any chemical weapons attack would quickly overwhelm U.S. incineration facilities. Cheeseman adds, however, that the model still does not completely validate the idea of landfill disposal. “The model clearly shows these chemical agents break down fairly quickly, largely due to hydrolysis by water,” he says. “But there’s no indication of the amounts that might be left on debris after an attack. For example, just how much sarin gas will be left on a piece of concrete exposed to it?”