Neutron activation analysis for trace elements. Elements depleted on lunar surface - Implications for origin of moon and meteorite influx rate Final report, 1 Aug. 1969 - 31 Jan. 1971

Neutron activation analysis for trace elements depleted on lunar surface with implications for origin of moon and meteorite influx rat

Plant uptake of americium, curium, and the chemical analog neodymium. [/sup 241/Am, /sup 244/Cm, /sup 147/Nd]

The plant uptake from several bulk soils has been determined for neodymium, a chemical analog to the transuranium elements americium and curium, and several other native rare earth elements as well. These investigations have demonstrated that neodymium, which has very similar chemical properties to americium and curium and should have a similar environmental behavior, does behave indistinquishably under both laboratory and field conditions. The uptake of the weathered or mobile forms of these elements from soils is expected to be governed primarily by their identical oxidation states and nearly identical ionic radii. This hypothesis is strongly supported by the chondritic (primordial) normalized rare earth element patterns in several plants. In these samples, the entire series of rare earth elements behaves as a smooth function of the REE ionic radii, as is also seen in the contiguous soils. This behavior suggests that the plant uptake of other ions with similar chemical properties (i.e., americium and curium) would also be governed by ionic size and charge