Af. Nisbet et al., LABORATORY INVESTIGATION INTO THE POTENTIAL EFFECTIVENESS OF SOIL-BASED COUNTERMEASURES FOR SOILS CONTAMINATED WITH RADIOCESIUM AND RADIOSTRONTIUM, Science of the total environment, 149(3), 1994, pp. 145-154
Accidental releases of radioactive material into the environment have
prompted the search for effective soil-based chemical treatments to re
duce the transfer of radiocaesium and radiostrontium along foodchains.
As field studies can be impractical and protracted, a simple laborato
ry method has been evaluated for use after an accident to predict the
effect that different soil treatments may have on radionuclide availab
ility to plants. The study involved a batch equilibrium approach in wh
ich in situ conditions were replicated by the use of field moist soils
and their associated soil solutions. The technique was used to invest
igate the effects of common agricultural treatments (potassium as sulp
hate of potash, calcium as garden lime and ammonium as ammonium sulpha
te) on the distribution of Cs-137, Sr-90, K and Ca between solid and l
iquid phases of loam, sand and peat soils. A treatment that decreased
the Cs-137+:K+ or Sr-90(2+):Ca2+ quotient in the liquid phase compared
with controls could be considered a potentially effective countermeas
ure for reducing uptake of the appropriate radionuclide by plants. Pot
assium decreased Cs-137+:K+ quotients in the liquid phase of all soil
types, and in peat in particular. The potential effectiveness of potas
sium as a soil based countermeasure for reducing radiocaesium uptake t
o plants in peat soils was supported by field evidence from highly org
anic soils in Cumbria. Application of the ammonium treatment increased
Cs-137+:K+ quotients in the liquid phase of all soil types and in the
sand in particular. As an increase in this ratio is associated with a
n enhanced uptake of radiocaesium by plants, the application of ammoni
um based fertilisers to soils contaminated with radiocaesium should th
erefore be considered very carefully. No firm conclusions could be rea
ched regarding the effectiveness of garden lime as a countermeasure be
cause of its low solubility and the very high calcium status of the ex
perimental soils at the start of the experiment.