Putting the lid on methyl bromide

Methyl bromide, which is used to fight plant diseases, is known to destroy the ozone layer. Now, Kamlesh Miglani of the directorate of plant protection's plant quarantine and fumigation section, has found a way of preventing the chemical from escaping into the atmosphere during its use in the fumigation of plants and seed stocks.

Miglani's discovery created ripples in scientific circles because scientists had almost abandoned efforts to find a substitute to the chemical, which is the largest reservoir of bromine atoms that catalytically destroy the ozone layer. By simple modifications in the conventional fumigation chambers, Miglani has controlled the release of methyl bromide, which is highly effective against many pests, insects, viruses, fungi and bacterial pathogens. The chamber's outlet is connected to a reservoir of alcoholic potassium hydroxide. The modification helps absorb upto 75 per cent of the fumigant during degassing, thus checking its release into the atmosphere.

The process is simple and inexpensive. The alcohol is distilled after the fumigation and can be reused, while the bromine in it settles down as potassium bromide.