Caesium, uptake

Broadley, M. R., Willey, N. J., Philippidis, C., and Dennis, E. R. (1999b). A comparison of caesium uptake kinetics in eight species of grass. J. Environ. Radioact. 46, 225-236. 

Willey, N. J., and Martin, M. H. (1997). A comparison of stable caesium uptake by six grass species of contrasting growth strategy. Environ. Pollut. 95, 311-317. 

Shaw G and Bell JNB (1991) Competitive effects of potassium and ammonium on caesium uptake kinetics in wheat. J Environ Radioact 13 283-296. 

Popplewell DS, Ham GJ, Johnson TE, et al. 1984. The uptake of plutonium-238, 239, 240, americium-241, strontium-90 and caesium-137 into potatoes. Sci Total Environ 38 173-181. 

Roca, M.C., and Vallejo, V.R., 1995, Effect of soil potassium and calcium on caesium and strontium uptake by plant roots. J. Environ. Radioac. 28 141-159. 

Shaw, G., 1993, Blockade by fertilisers of caesium and strontium uptake into crops effects on the root uptake process. 5ci. Total Environ. 137 119-133. 

Bradbury, M. H. Baeyens, B. 2000. A generalised sorption model for the concentration dependent uptake of caesium by argillaceous rocks. Journal of Contaminant Hydrology, 42, 141-163. 

Barber, D.A. (1964) Influence of soil organic matter as the uptake of caesium-137 by perennial rye grass. Nature, 204,1326. 

Most radioactive particles and vapours, once deposited, are held rather firmly on surfaces, but resuspension does occur. A radioactive particle may be blown off the surface, or, more probably, the fragment of soil or vegetation to which it is attached may become airborne. This occurs most readily where soils and vegetation are dry and friable. Most nuclear bomb tests and experimental dispersions of fissile material have taken place in arid regions, but there is also the possibility of resuspension from agricultural and urban land, as an aftermath of accidental dispersion. This is particularly relevant to plutonium and other actinide elements, which are very toxic, and are absorbed slowly from the lung, but are poorly absorbed from the digestive tract. Inhalation of resuspended activity may be the most important route of human uptake for actinide elements, whereas entry into food chains is critical for fission products such as strontium and caesium. 

In solution culture experiments both strontium and caesium show hyperbolic absorption isotherms with respect to the external concentration of the element. Figure 7-15 (a) shows an example of a typical uptake isotherm for Sr while Shaw and Bell (1989) have demonstrated a similar isotherm for Cs. Baker (1981) has referred to such plant uptake responses as accumulator functions and has identified these as being typical of the absorption of elements over which plants can exert some degree of physiological control. Typically, the nutrient elements, including K and Ca, exhibit such isotherms and it can be postulated from the similarity in the uptake patterns of K and Cs on the one hand and Ca and Sr on the other that the radioions share, to some extent, the same uptake mechanisms as the nutrient ions. This has several important implications. Firstly, the direct competition for uptake sites between radioions and nutrient ions means that the external (soil) concentration of one is increased at the expense of the uptake of the other as the nutrient ions in question are vastly more abundant in soils than radioions it is K and Ca which will be effective in competitively excluding Cs and Sr, respectively. Secondly, the kinetics of this competition are concentration-dependent, so the assumption of first order kinetic movements of... 

The uptake of Cs by uncontaminated Dounreay offshore sand was investigated to confirm which mineral were involved in caesium sorption (DST-R 250pm fraction was tested). The results showed that the more-magnetic mineral fraction had a higher sorption capacity than the non-magnetic fractions. It is notable that the interaction time of 24hr may have been too short to establish maximum uptake potential. 

Caesium in river > uptake by fish > human consumption This can be a critical path. 

Caesium in river > irrigation water > uptake in crops > human consumption... 

In August and September 1978, in response to the high uptake of caesium in the population—then composed of the 139 Bikinians who had returned to Bikini Atoll— officials of the Trust Territory decided to relocate the Bikinians again from their atoll, back to Kili Island and to Ejit Island at Majuro Atoll. 

Regular measurements of activity in local foodstuffs should be made to assess the effectiveness of the measures taken. A simple, local whole body monitor and training in its use should be provided as a further means of enabling potential inhabitants to satisfy themselves that there is no significant uptake of caesium into their bodies. (After lAEA-RAR series, 1998). 

Bengtsson A, Hansson P (1990) Measures against mercury and caesium in lake fish and wild animals. Project 3. Environmental project Sundsvall-Timra (in Swedish) 29 pp Bergman R, Danell K, Ericsson A, Grip H, Johansson L, Nelin P, Nylen T (1988) Uptake, re-distribution and transport of radionuclides in a forest ecosystem (in Swedish). FOA-rapport E 40040, Sept. 1988, SLU, UmeS... 

---