Radiocesium Uptake by One-Year-Old Willows Planted as Short Rotation Coppice
2000
High radioactivity concentrations in foodcrops grown in areas contaminated by the Chernobyl accident continue to justify the consideration of a change in land use. Production of biofuel may be one of the alternatives to food production. However, present knowledge about radionuclide cycling in such systems is limited. In the present study, radiocesium uptake and distribution were measured in a willow (Salix viminalis L. var. Orm) short rotation coppice (SRC) stand. This system allows production of energy from the harvested biomass. Experimental plots were established on two soil types of contrasting texture (loamy versus sandy), and contaminated with 8 × 10⁶ Bq ¹³⁴Cs m⁻². Concentrations of ¹³⁴Cs were measured in wood, litter, roots, and cuttings after 1 yr of growth. At the end of the growing season, only 0.0012% (loamy soil) and 0.0065% (sandy soil) of the initial radiocesium was transferred to the plant biomass (including belowground plant parts). Stem wood contained the lowest concentration of ¹³⁴Cs among all plant parts analyzed. Wood radiocesium concentrations were 82 Bq kg⁻¹ for the loamy soil and 192 Bq kg⁻¹ for the sandy soil. These values are well below the exemption limit for fuel wood put forward in the Commonwealth of Independent States (CIS) (740 Bq kg⁻¹). Even at this high soil contamination level, radiocesium concentrations in wood do not exceed appreciably the naturally occuring ⁴⁰K content in the wood (135 Bq kg⁻¹).
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