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Accumulation of Cesium‐137 and Strontium‐90 in Ponderosa Pine and Monterey Pine Seedlings

1993; Wiley; Volume: 22; Issue: 4 Linguagem: Inglês

10.2134/jeq1993.00472425002200040016x

1537-2537

James A. Entry, Paul T. Rygiewicz, William H. Emmingham,

Nuclear and radioactivity studies

Abstract Because ponderosa pine [ Pinus ponderosa (Dougl. ex Laws)] and Monterey pine ( P. radiata D Don) have exceptionally fast growth rates and their abscised needles are not readily dispersed by wind, these species may be valuable for removing radioisotopes from contaminated soils. Ponderosa and Monterey pine seedlings were tested for their ability to accumulate 137 Cs and 90 Sr—characteristic radioisotopes of nuclear fallout—from contaminated soil. Seedlings were grown for 3 mo in 165 cm 3 sphagnum peat moss/perlite (1:1 V/V) in a growth chamber. In Exp. 1, seedling accumulation of 137 Cs and 90 Sr after 1 mo of exposure was measured. In Exp. 2, seedling accumulation of the radioisotopes during different‐length exposures was measured. Seedling accumulation of 137 Cs and 90 Sr at different concentrations of the radioisotopes in the growth medium was measured in Exp. 3. Ponderosa pine accumulated 6.3% of the 137 Cs and 1.5% of the 90 Sr present in the growth medium after 1 mo; Monterey pine accumulated 8.3% of the 137 Cs and 4.5% of the 90 Sr. Accumulation of 137 Cs and 90 Sr by both coniferous species was curvilinearly related to duration of exposure. Accumulation of 137 Cs and 90 Sr by both species increased with increasing concentration in the growth medium and correlated curvilinearly with radioisotope concentration in the growth medium. Large areas throughout the world are contaminated with 137 Cs and 90 Sr as a result of nuclear weapons testing or atomic reactor accidents. The ability of trees to sequester and store 137 Cs and 90 Sr introduces the possibility of using reforestation to remediate contaminated soils.