Thorium radionuclides

Uranium compounds Many salts are irritating to the respiratory tract soluble salts are potent kidney toxins. Uranium is a weakly radioactive element (alpha emitter) decays to the radionuclide, thorium 230. Uranium has the potential to cause radiation injury to the lungs, tracheobronchial lymph nodes, bone marrow, and skin. 0.2 mg/m (soluble and Insoluble compounds, as U), A1 tOrng/m Dense, silvery-white, lustrous metal. Finely divided powders are pyrophoric. Radioactive. 

In a different example, traceability in the amount-of-substance analysis of natural potassium, thorium, and uranium by the method of passive gamma-ray spectrometry was demonstrated by Nir-El (1997). For an absolute quantitative determination, accurate values of two parameters were required (i) the emission probability of a gamma-ray in the decay of the respective indicator radionuclides, and (2) the detection efficiency of that gamma-ray. This work employed a number of CRMs in the critical calibration of the detection efficiency of the gamma-ray spectrometer and the establishment of precise emission probabilities. The latter results compared well with literature values and provided smaller uncertainties for several gamma-rays that were critical for the traceabUity claim. The amount-of-substance analytical results of the long lived naturally occurring radionucHdes K, Th, and... 

Cochran JK, Masque P (2003) Short-lived U/Th-series radionuclides in the ocean tracers for scavenging rates, export fluxes and particle dynamics. Rev Mineral Geochem 52 461-492 Cohen AS, O Nions RK (1991) Precise determination of femtogram quantities of radium by thermal ionization mass spectrometry. Anal Chem 63 2705-2708 Cohen AS, Belshaw NS, O Nions RK (1992) High precision uranium, thorium, and radium isotope ratio measurements by high dynamic range thermal ionization mass spectrometry. Inti J Mass Spectrom Ion Processes 116 71-81... 

Neder H, Heusser G, Laubenstein M (2000) Low-level y-ray germanium-spectrometer to measure veiy low primordial radionuclide concentrations. ApplRadiat Isot 53 191-195 Palacz ZA, Freedman PA, Walder AJ (1992) Thorium isotope ratio measurements at high abundance sensitivity using a VG 54-30, an energy-filtered thermal ionization mass spectrometer. Chem Geol 101 157-165... 

Cochran JK, Bacon MP, Krishnaswami S, Turekian KK (1983) °Po and °Pb distributions in the central and eastern Indian Ocean. Earth Planet Sci Lett 65 433-445 Cochran JK, Livingston HD, Hirschberg DJ, Surprenant LD (1987) Natural and anthropogenic radionuclide distributions in the northwest Atlantic-ocean. Earth Planet Sci Lett 84 135-152 Cochran JK (1992) The oceanic chemistiy of the uranium and thorium-series nuclides In Uranium-series disequihbrium applications to earth, marine, and environmental sciences. Ivanovich M, Harmon RS (eds) Oxford University Press, New York, p 334-395... 

Vigier N, Bourdon B, Turner S, Allegre CJ (2001) Erosion timescales derived from U-decay series measurements in rivers. Earth Planet Sci Lett 193 549-563 von Gunten HR, Roessler E, Lowson RT, Reid PD, Short SA (1999) Distribution of uranium- and thorium series radionuclides in mineral phases of a weathered lateritic transect of a uranium ore body. Chem Geol 160 225-240... 

Moore WS (1992) Radionuclides of the uranium and thorium decay series in the estuarine enviromnent. In Uranium-series Disequilibrium Applications to Earth, Marine and Enviromnental Sciences. Ivanovich M, Harmon RS (eds) Clarendon Press, Oxford, p 396-422 Moore WS (1996) Large groundwater inputs to coastal waters revealed by Tla emichments. Nature 380 612-614... 

At present, there are no widely distributed certified reference materials containing all of the radionuclides in the uranium and thorium decay series. Such reference materials are needed to calibrate instruments that make radionuclide measurements and to compare analytical results from different laboratories. The most critical need is for reference materials in the 235U decay series 231Pa, 227Ac, and 223Ra. 

Individual Standard Reference Materials containing 14C, 3H, and some naturally occurring uranium and thorium series radionuclides are available from the National Institute of Standards and Technology (NIST). These include ... 

Radium, thorium, and other radionuclides accumulate in uranium mill tailings. The potential environmental effects of these radionuclides has become of increasing concern to the public. In the future, it may be necessary to modify existing uranium recovery processes to accommodate removal of radium and perhaps other radioactive decay products of uranium. 

When thorium emits alpha particles, it disintegrates into other daughter radionuclides (radioactive materials), such as radium-226 and radon-222 (from thorium-230 in the uranium-238 decay series) or radium-228 and thoron (radon-220 from thorium-232 in the thorium decay series). It eventually decays to stable lead-208 or -206, which is not radioactive. More information about the decay of thorium can be found in Chapter 3. The toxicological characteristics of radon, radium, and lead are the subject of separate ATSDR Toxicological profiles. 

Carpenter R, Beasley TM, Zahnie D, et al. 1987. Cycling of fallout (plutonium, americium-241, cesium-137) and natural (uranium, thorium, lead-210) radionuclides in Washington continental slope sediments. Geochim Cosmochim Acta 51 1897-1921. 

Gbssner W. 1982. Thorium II Biological effects of thorium. In Galle P, Masse R, eds. Radionuclide Metab Toxic Proc Symp. Masson Publ., 273-280. 

Joshi SR. 1987. Nondestructive determination of selected uranium and thorium-series radionuclides in biological samples. Health Phys 53 417-420. 

Laul JC, Smith MR, Thomas CW, et al. 1987. Analysis of natural radionuclides from uranium and thorium series in briney groundwaters. J Radioanal NucI Chem 110 101-112. 

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