Modeling of 137Cs migration in soils using an 80-year soil archive: role of fertilizers and agricultural amendments

Abstract

An 80-year soil archive, the 42-plot experimental design at the INRA in Versailles (France), is used here to study long-term contamination by 137Cs atmospheric deposition and the fate of this radioisotope when associated with various agricultural practices: fallow land, KCl, NH4(NO3), superphosphate fertilizers, horse manure and lime amendments. The pertinence of a simple box model, where radiocaesium is supposed to move downward by convectional mechanisms, is checked using samples from control plots which had been neither amended, nor cultivated since 1928. This simple model presents the advantage of depending on only two parameters: alpha, a proportional factor allowing the historical atmospheric 137Cs fluxes to be reconstructed locally, and k, an annual loss coefficient from the plow horizon. Another pseudo-unknown is however necessary to run the model: the shape of historical 137Cs deposition, but this function can be easily computed by merging several curves previously established by other surveys. A loss of approximately 1.5% per year from the plow horizon, combined with appropriate fluxes, provides good concordance between simulated and measured values. In the 0-25cm horizon, the residence half time is found to be approximately 18yr (including both migration and radioactive decay). Migration rate constants are also calculated for some plots receiving continuous long-term agricultural treatments. Comparison with the control plots reveals significant influence of amendments on 137Cs mobility in these soils developed from a unique genoform.

134Cs uptake by four plant species and Cs–K relations in the soil–plant system as affected by Ca(OH)2 application to an acid soil

“…These findings are in agreement with previous studies that reported similar changes in 134 Cs concentration in plants due to soil liming (Jackson and Nisbet, 1990;Lembrechts, 1993;Nisbet et al, 1993;Putyatin and Seraya, 2007;Choi et al, 2008;Monna et al, 2009). However, the variability of 134 Cs plant concentration is much lower than that observed in a previous experiment (z40 for radish roots and z200 for cucumber fruits) when six plants were grown on eight different mineral soils (Skarlou et al, 1996).…”

“…Soil pH ! 7.0 was shown to be favourable to the creation of variable charges on clay minerals and organic matter, thus increasing the sorption of 137 Cs (Monna et al, 2009 and references therein). Giannakopoulou et al (2007) also reported that the maximum Cs sorption in soils was observed at soil pH ¼ 8.…”

“…Most of the existing evidence suggests that there is a correlation of Cs uptake with soil pH, clay content, soil potassium (K)-status and clay minerals (Schuller et al, 1988;Skarlou et al, 1996Skarlou et al, , 1999Gerzabek et al, 1998;Massas et al, 2002;Kruse-Irmer and Gianni, 2003;Rahman and Voigt, 2004;Melnitchouck and Hodson, 2004). Liming of acid soils is also reported to provide an effective countermeasure to reduce Cs availability to plants (Jackson and Nisbet, 1990;Lembrechts, 1993;Nisbet et al, 1993;Avery, 1996;Putyatin and Seraya, 2007;Monna et al, 2009;Zibold et al, 2009).…”

Deposition of artificial radionuclides from atmospheric Nuclear Weapon Tests estimated by soil inventories in French areas low-impacted by Chernobyl

“…137 Cs and 241 Am is dated between 1963 and 1975 [Fig. 6], which is in good agreement with records in western Europe(Monna et al, 2009 -…”

Centennial Fertilization-Induced Soil Processes Control Trace Metal Dynamics. Lessons from a Long-Term Bare Fallow Experiment

“…In the absence of elemental uptake by plants, the nonamended plots of the 42-plots experiment act as valuable recorders of atmospheric deposition [12,13,37]. For the reference plots, significant positive element budgets were observed for Na, Cd, Co, Cr, Mo, Pb, and Zn (Table 1, Table 2, and Table 4), elements that are frequently reported in atmospheric deposition [32,38].…”