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Nuclear weapons fallout 137Cs in temperate and tropical pine forest soils, 50?years post-deposition

Itthipoonthanakorn, T.; Dann, S.E.; Crout, N.M.J.; Shaw, G.


T. Itthipoonthanakorn

S.E. Dann

Interim Pro-Vice Chancellor For Research & Knowledge Exchange

G. Shaw


Following nuclear releases to the environment, 137Cs (half-life 30 years) is a long-term contaminant of many ecosystems, including forests. We recently sampled soils under pine forests in temperate and tropical climates to test the hypothesis that migration of 137Cs, 50 years after nuclear weapons fallout, is coupled with organic matter (OM) accumulation in these soils. Depth profiles of 137Cs, naturally-occurring 210Pb and weapons-derived 241Am were measured. After 50 years, migration of 137Cs into the temperate and tropical soils is limited to half-depths of 7–8 cm and 2–3 cm, respectively. At both locations, most 137Cs is associated with OM that accumulated from the early to mid-1960s. Illite, which immobilises radiocaesium, was undetectable by X-ray diffraction in the layer of peak 137Cs accumulation in the temperate forest soil, but apparent in the zone of peak concentration in the tropical soil. Data indicate that long-term (50 year) fate of 137Cs in organic-rich, temperate forest soil is coupled with OM accumulation; fixation of 137Cs by illite is more important in the tropical forest soil where OM is rapidly decomposed. Models of long-term radiocaesium migration in forest soils should explicitly account for the role of OM, especially when considering forests under contrasting climatic regimes.


Itthipoonthanakorn, T., Dann, S., Crout, N., & Shaw, G. (2019). Nuclear weapons fallout 137Cs in temperate and tropical pine forest soils, 50?years post-deposition. Science of the Total Environment, 660, 807-816.

Journal Article Type Article
Acceptance Date Jan 7, 2019
Online Publication Date Jan 8, 2019
Publication Date Apr 10, 2019
Deposit Date Jan 9, 2019
Publicly Available Date Jan 9, 2019
Journal Science of The Total Environment
Print ISSN 0048-9697
Electronic ISSN 1879-1026
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 660
Pages 807-816
Keywords Environmental Engineering; Waste Management and Disposal; Pollution; Environmental Chemistry
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