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Title: Release and transport of radium during weathering in central and north Florida

Thesis/Dissertation ·
OSTI ID:5282244

Samples of fresh and weathered Florida phosphate rock were analyzed for several uranium decay-series radionuclides. In bulk samples, almost all radionuclides display higher activities in weathered samples compared to fresh material. /sup 230/Th is normally in isotopic equilibrium with /sup 234/U in fresh material but often depleted and occasionally enriched in highly weathered samples. /sup 226/Ra is close to equilibrium with its parent /sup 230/Th in most samples. /sup 210/Pb//sup 226/Ra activity ratios were less than 1.00, as expected, due to radon leakage. Less than unity activity ratios of /sup 210/Po//sup 210/Pb in a few weathered samples indicates a preferential release of /sup 210/Po under some conditions. Based on over 2 years of measurements, the mean concentration of dissolved /sup 226/Ra in the Suwannee River is 26 dpm 100L/sup -1/, 2-4 times higher than most other world's rivers. The annual long-term discharge of dissolved /sup 226/Ra to the Gulf of Mexico is approximately 3.3 x 10/sup 12/ dpm yr/sup -1/, about two orders of magnitude less than that discharged by the Mississippi River. Upon entrance into the Gulf, a portion of the particulate radium is released accounting for part of the high /sup 226/Ra concentrations observed in the estuary. Other possible radium sources to the estuary include submarine springs, seepage of coastal ground water and salt marshes.

Research Organization:
Florida State Univ., Tallahassee (USA)
OSTI ID:
5282244
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English