Form and behavior of radium, uranium, and thorium in central Pennsylvania soils derived from dolomite

• Published in: Geophysical research letters Vol. 17; no. 6; pp. 833 - 836
• Main Authors: Greeman, Daniel J., Rose, Arthur W., Jester, William A.
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.05.1990
• Subjects: 540230 - Environment, Terrestrial- Radioactive Materials Monitoring & Transport- (1990-); ACTINIDE ISOTOPES; ACTINIDE NUCLEI; ALKALINE EARTH ISOTOPES; ALKALINE EARTH METAL COMPOUNDS; ALKALINE EARTH METALS; ALPHA DECAY RADIOISOTOPES; BARIUM; CALCIUM CARBONATES; CALCIUM COMPOUNDS; CARBON 14 DECAY RADIOISOTOPES; CARBON COMPOUNDS; CARBONATE MINERALS; CARBONATE ROCKS; CARBONATES; CHEMISTRY; DEPTH; DIMENSIONS; DISTRIBUTION; DOLOMITE; ECOLOGICAL CONCENTRATION; ELEMENTS; Emission; ENRICHMENT; ENVIRONMENTAL SCIENCES; ENVIRONMENTAL TRANSPORT; EVEN-EVEN NUCLEI; EXTRACTION; FEDERAL REGION III; FLUIDS; GAS ANALYSIS; GASES; GEOLOGIC AGES; HEAVY ION DECAY RADIOISOTOPES; HEAVY NUCLEI; Iron; ISOTOPES; MAGNESIUM CARBONATES; MAGNESIUM COMPOUNDS; MASS TRANSFER; METALS; MINERALS; NONMETALS; NORTH AMERICA; NUCLEI; ORDOVICIAN PERIOD; ORGANIC MATTER; OXYGEN COMPOUNDS; PALEOZOIC ERA; PENNSYLVANIA; PHYSICAL PROPERTIES; PLANTS; RADIOISOTOPES; Radium; RADIUM 226; RADIUM ISOTOPES; RADON; RARE GASES; RECYCLING; ROCKS; SAMPLING; SEDIMENTARY ROCKS; SEPARATION PROCESSES; SOIL CHEMISTRY; SOILS; SOLVENT EXTRACTION; Thorium; THORIUM 232; THORIUM ISOTOPES; UPTAKE; URANIUM 238; URANIUM ISOTOPES; USA; Vegetation; YEARS LIVING RADIOISOTOPES; USA, Pennsylvania
• DOI: 10.1029/GL017i006p00833
• ISSN: 0094-8276

In a pair of well‐ and poorly‐drained soils developed on Ordovician carbonate rocks in Central Pennsylvania, the distribution with depth and chemical form of 238U, 232Th, and 226Ra have been compared to soil properties. Concentrations range from 3.3 to 8 ppm U and 6.3 to 11 ppm Th in the soils. Although radium is in equilibrium with U at depth in both soils, in surficial A‐horizons Ra is well in excess of U (165–180%). Ra and U are enriched 10X‐12X over the bedrock. Th is enriched, along with Al and Fe, by 20X. Progressive selective extractions for U, Th, and Ra in soil show half the radium occurring in pedogenic phases, chiefly in the organic fractions (24% of total Ra). By contrast, <1% of the U and Th occurs in any of the organic fractions; up to 80% occurs in the silt and clay fractions with a significant occurrence in the Fe‐oxides, up to 50% for Th. Ra and chemically similar Ba are cycled by vegetation but Ra is retained in soil, bound in humified soil organic matter while Ba is not. Radon emanation of these soils (8–27%) can be almost entirely attributed to highly emanative Ra bound in organic matter. In these soils the action of vegetation leads to high soil gas radon by maintaining high Ra concentration and enhancing its emanating power.