Rapid degradation of atmospheric methyl bromide in soils
Abstract
METHYL bromide (CH3Br), a widely used agricultural fumigant, may be an important source of atmospheric bromine radicals, which destroy stratospheric ozone110. In current models of this compound's atmospheric behaviour, the main sinks are taken to be oxidation by hydroxyl radicals, photolysis and uptake by the oceans15,7,9,10. But there is also evidence that CH3Br is consumed in soils8,1113. Here we report laboratory and field experiments which show that, when exposed to a variety of soil types at low mixing ratios, CH3Br is rapidly and irreversibly removed to below the levels found in the global atmosphere. We show that the uptake process is bacterially mediated. We estimate the global annual soil sink to be 42 ± 32 Gg; coupled with other removal mechanisms, this suggests an atmospheric lifetime for CH3Br of about 0.8 yr, just half the previous best estimate9, and an ozone depletion potential that is about 30% smaller than the previous estimate1.
Department
Earth Systems Research Center
Publication Date
10-26-1995
Journal Title
Nature
Publisher
Springer Nature
Digital Object Identifier (DOI)
Document Type
Article
Recommended Citation
Shorter, J.H., C.E. Kolb, R.A. Kerwin, P.M. Crill, M.E. Hines, R.W. Talbot, and R.C. Harriss (1995), Rapid degradation of atmospheric methyl bromide in soils, Nature, 377 (6551), 717-719.