Cesium uptake

Clinoptilolite amendments to soil have greatly reduced cesium uptake by plants (e.g. on Bikini AtoU) and clinoptilolite from the Belli Plest deposit in Bulgaria was dropped by air to help control the Chernobyl accident. Finally, both zeolite A and a chabazite played key roles in the Three Mile Island clean-up program, again to scavenge Cs radioisotopes. 

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

The bioavailability of cesium for plants depends on the pH-value of the soil (Wytten-bach et al., 1991), and is high on soils with low pH-values, as are found on moors and in forests. The bioavailability is markedly lower in soils with higher pH-values such as in farmed soils (e.g., meadows or pastures) and other agricultural soils where the pH-value is maintained at 6-8 by fertilizing. A high potassium concentration in the soil has also been shown to lead to a decrease in cesium uptake by plants (Shaw and Bell, 1991). 

The contamination of the game is species-dependent (see Table 1-5.1), due mainly to the types of plant eaten by the animals, as different plant species absorb different amounts of radiocesium from the soil (Table 1-5.3). Plant species gro ving vithin the same region also exhibit large variation in cesium uptake and accumulation (Table 1-5.4). Examples of this include mushroom species found in the Bavarian Forest and the Cortinarius species, vhich retain high cesium levels (Haffelder, 1995, Steine et ah, 2002). 

Also shown in this Figure 5.20 are the secondary ion yield variations noted. These stem from the differential uptake of Cesium within the respective grains, which, in turn, results from the differential ionization yields as well as differential sputter rates. Note As discussed in Section 3.2.2.2.2, increased Cesium uptake occurs with decreasing sputter rates, hence the greater signal intensities noted from the shallower regions in Figure 5.20. 

Bramham J and Riddell FG (1994) Cesium uptake studies on human erythrocytes. Journal of Inorganic Biochemistry 53 169-176. 

Durand JP, Milcent MC, Goudard F, et al. 1994. Chemical behavior of three radionuclides (cesium, americium and technetium) and their uptake at the cystosolic level in aquatic organisms. Biochem Mol Biol Int 33(3) 521-534. 

Higher phytoextraction coefficients indicate higher metal uptake. The effectiveness of phytoextraction can be limited by the sorption of metals to soil particles and the low solubility of the metals however, metals can be solubilized through the addition of acids or chelating agents and so allow uptake of the contaminant by the plant. Ethylene diamine tetra-acetic acid (EDTA), citric acid, and ammonium nitrate have been reported to help in the solubilization of lead, uranium, and cesium... 

Figure 2. Adsorption of radionuclides on rock minerals, (a) (Topj Photomacrograph of a polished granite surface after exposure to a solution of radio-cesium Dark areas are exposed mica crystallites, (b) (Bottom) Autoradiograph of same surface showing uptake of cesium by mica.

Mardan A., Rumana, A., Mehmood, A., RAza, S. M. and Ghaffar, A., Preparation of Silica Cobalt Hexacyanoferrate Composite Ion Exchanger and Its Uptake Behavior for Cesium , Sep. Puri. Technol. 16 (1999) 147. 

Figure 4 shows metal uptakes as a function of sorption time at 1173 K. No additional metal uptakes were found after about 60 hr. Of the three metal vapors, cesium exhibited the largest equilibrium uptake. In addition to capturing the metal, ideal sorbents would retain metal species in the sorbent matrices when they are disposed of. The results of the... 

Plant roots take up cesium readily because of its similarity with the essential nutrient, potassium. Plants differ in their accumulation of cesium (Broadley and Willey, 1997 Lasat et al., 1998 Broadley et al., 1999a,b). This may be due to differences in rooting pattern, root uptake, or translocation within the plant, but the cause is not clearly identified. Cesium is mobile within plants and has similar trends in the translocation within plants to K (Broadley and Willey, 1997 Zhu and Smolders, 2000). Rather little is known about differences between species in their capacity to discriminate between Cs and K. There appears to be a threshold below which Cs uptake by roots increases with decreasing K concentration. The value of this threshold has been reported to be 1 mmol L , 250 Itmol L , or 20 Itmol (Shaw and Bell, 1989, 1991 Shaw et al., 1992 Buysse et al., 1996 Smolders et al., 1996 Zhu, 2001). This inhibition may be due in part to increased efflux of absorbed Cs (Zhu et al., 1999). Model prediction of Cs uptake often overpredict uptake and are improved if account is take of soil-solution potassium concentration below 1 mM (Smolders et al., 1997 Absolom et al., 1999 Roca-Jove and Vallejo-Calzada, 2000), Cs uptake is found to be enhanced by potassium starvation (Jones et al., 1998 Broadley et al., 1999b Zhu et al., 2000), but the effect is short-lived (Willey and Martin, 1997 Staunton et al., 2003). 

Avery, S. V. (1995). Cesium accumulation by microorganisms uptake mechanisms, cation competition, compartmentalization and toxicity. J. Ind. Microbiol. 14, 76-84. 

Kodaira K, Tsumura A, Kobayashi H. 1973. Uptake of radioactive strontium and cesium in rice plants (1) Accumulation of Sr and Cs in rice grains through roots. J Radiat Res 14 31-39. 

D. The uptake by the body of radioisotopes can be blocked in some cases. For example, potassium iodide or iodate if given prior to or soon after an intake of radioiodine, will reduce the uptake of radioiodine by the thyroid gland. Similarly, orally administered Prussian Blue will reduce the absorption of cesium from the gut and Alginate will reduce strontium absorption. No policy exists which would allow for NATO forces to stock and issue chelators. 

IvSHiNA IB, Peshkue TA and Korobov VP (2002) Efficient uptake of cesium ions by Rhodococcus cells. Microbiology 71 357-361. 

The cesium contents of soils vary analogously with their potassium contents (Oughton and Day, 1993). Forest and moor soils have lower potassium contents than farmed soils, where the fertilizers used substitute for potassium losses following uptake by the vegetation. The typical cesium content of pastures is 1-2 mgkg (Oughton and Day, 1993), while the Cs contents of soil may range from 0.5 to 20 mg kg (Shaw and Bell, 1991). 

Fuhrmann M, Lasat MM, Ebbs SD, Kocliian LV, Cornish J (2002) Uptake of cesium-137 and strontium-90 from contaminated soil by three plant species application to phytoremediation. J Environ Qual 31 904-909... 

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