Effect of soil calcium on uranium and radium uptake by wheat plants

The uptake of naturally occurring uranium and radium by wheat plants growing in soils under natural field conditions and representing two major soil groups alluvial and laterite in India was studied. The presence of other nutrient cations in soil which can exert a synergistic or antagonistic effect on the uptake of radionuclides was investigated. Calcium being divalent and an essential nutrient was expected to affect the uptake of radium. The study shows that the quantity of calcium in soil and its availability for uptake by plants markedly affects the uptake of uranium also. The observed ratio (OR) for uptake of uranium and radium to calcium by plants from soil was calculated. The OR for radium are 0.5 for roots, 0.3 for shoot and husks and close to 1 for grains. The OR for uranium are an order of magnitude less than that for radium. The plant is observed to show discrimination for uptake of elements, preferring to pick up essential nutrients over other elements present in soil. (author)