Supply rates of natural U-Th series of radionuclides from aquifer solids into groundwater

Journal Article · Thu Jun 15 04:00:00 EDT 1995 · Geophysical Research Letters

DOI:https://doi.org/10.1029/95GL01006· OSTI ID:166798

Hussain, N ^[1]

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1. Univ. of Delaware, Newark, DE (United States)

Supply rates of {sup 224}Ra and {sup 212}Pb from zircon and monazite grains to the aqueous phase are experimentally determined by dispersing these minerals in 1N nitric acid and PRL (Physical Research Laboratory) groundwater. In nitric acid medium, recoiled {sup 224}Ra and {sup 212}Pb behave conservatively and are not removed by solid surfaces. However, in groundwater, {sup 212}Pb is removed from the aqueous phase. A model relating the actual supply ratio of {sup 212}Pb/{sup 224}Ra, the measured activities of {sup 224}Ra and {sup 212}Pb in the leachates at different times of contact and the first order removal rate constant of {sup 212}Pb is developed. At steady state, the supply ratio of {sup 212}Pb/{sup 224}Ra in the nitric acid from zircon and in groundwater from monazite is evaluated to be a unique value 2.3{+-}0.3 which agrees with the model predicted value of 2.67 based on alpha recoil supply of the nuclides and their precursors. The residence time of {sup 212}Pb in groundwater, with respect to its first order removal, is estimated to be of the order of 39 minutes. 10 refs., 2 figs., 2 tabs.

• OSTI ID: 166798
• Journal Information: Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 12 Vol. 22; ISSN GPRLAJ; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ENVIRONMENTAL TRANSPORT
GROUND WATER
LEACHING
LEAD 212
MONAZITES
NITRIC ACID
RADIUM 232
ZIRCON