Values for abundances are difficult to determine with much certainty, so all values should be treated with some caution, especially so for the less common elements. Local concentrations of any element can vary from those given here by orders of magnitude. One tonne of pitchblende might yield about 0.15 g of radium.
Recovery is costly.
Some estimates suggest that every square kilometre of soil to a depth of a 40 cm contains about 1 g of radium.