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Estimation of the acute cesium toxicity by the microbial assay for risk assessment (MARA) test

Bronowska M., Stęborowski R., Bystrzejewska-Piotrowska G.

Nukleonika

2013

Vol. 58, No. 4

481--485

The microbial assay for risk assessment (MARA) test was used for acute cesium toxicity evaluation in water solutions. The test contained 11 different microorganisms with a wide spectrum of sensitivity. The resistance of microorganisms to cesium was characterized as follows: microbial toxic concentration (MTC), half maximal inhibitory concentration (IC50), maximal inhibitory concentration (IC100). The sensitivity to cesium was characterized by the lowest observed effect level (LOEL). High levels of sensitivity in the range 3.1–6.3 mM were shown by the following microorganisms: Serratia rubidaea > Pseudomonas aurantiaca, Delftia acidovorans, Citrobacter freundii, Staphylococcus warneri. Lower levels of sensitivity (up to 16 mM) were noted for Comamonas testosteroni, Microbacterium species, Kurthia gibsonii, Pichia anomala, whereas that in the range 24–31 mM for Brevundimonas diminuta > Enterococcus casseliflavus. High resistance to Cs+ was found for E. casseliflavus (MTC 86.9 g/l) > the yeast – P. anomala (MTC 19.3 g/l) > K. gibsoni (MTC 17.4 g/l) > B. diminuta (MTC 13.4 g/l). The phenomenon of resistance of enterococcus and yeast strains was discussed.

Resistance of heather plants (Calluna vulgaris L.) to cesium toxicity

Bystrzejewska-Piotrowska G., Drożdż A., Stęborowski R.

Nukleonika

2005

Vol. 50, nr 1

31-35

Experiments were carried out to determine uptake and distribution of 137Cs, and total isotopes of Cs and K in plants of heather (Calluna vulgaris) growing at two levels of CsCl: 0.03 and 0.3 mM. Levels of Cs and K were determined in soil and in parts of plants: roots, stem, leaves and flowers. Also calculated were: (i) transfer factor of Cs and K from soil to parts of plant and (ii) discrimination of K by Cs during the transport of Cs from roots to aboveground parts of plants, expressed as K/Cs discrimination factor. The results confirmed that heather plants are hyper-accumulators of cesium, because the accumulation of Cs in shoot was much greater than in roots. The K level in heather did not change at Cs concentrations as high as 8-fold Cs level in this plant. Heather plants seem to be relatively resistant to cesium toxicity at 0.3 mM of CsCl; the effect of exposure to CsCl at this concentration was exerted only on roots, without affecting leaves and flowers. These results supply new information on the interactions between Cs and K nutrition in plants; they also point to a possible role of heather in redistribution of the radiocesium pollution in the forest ecosystem.