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Sequential Extractions for the Study of Radiocesium and Radiostrontium Dynamics in Mineral and Organic Soils from Western Europe and Chernobyl Areas

1999; American Chemical Society; Volume: 33; Issue: 6 Linguagem: Inglês

10.1021/es980720u

1520-5851

Anna Rigol, María Roig, M. Vidal, G. Rauret,

Radioactive element chemistry and processing

To study radiostrontium (RSr) and radiocesium (RCs) aging in soils, three sequential extraction schemes were used on Mediterranean loamy and loam-sandy soils, podsols and peaty podsols from the area near Chernobyl, and peats from Western Europe. Aging was quantified by changes in radionuclide distribution. Two factors were thought to affect radionuclide distribution: time elapsed since contamination and drying−wetting cycles. Changes in radionuclide distribution were of low significance in Mediterranean loamy and loam-sandy soils in the short term, even after drying−wetting cycles. In the short term, podsols and peaty podsols showed a decrease in the RSr exchangeable fraction in the laboratory samples (20−25% decrease), whereas samples taken 6 years after contamination did not show any further decrease. For RCs in podsols and peaty-podsols, the application of drying−wetting cycles for 9 months led to observe a 2−3-fold decrease in the exchangeable fraction, whereas time alone did not lead to any change. No RCs aging was observed in peats with a low or almost negligible content of mineral matter, low base saturation and low interception potential for RCs, even after drying−wetting cycles. Finally, changes in the radionuclide exchangeable fraction over time in these soils corresponded to changes in transfer factors over a similar period.