Written by John D. Dalton to the late Jane Jones of NPWA, December 20, 1999:
>> >Beryllium is highly persistent in water with a half-life of greater than >> >200 days. (The half-life of a pollutant is the amount of time it takes >for >> >one-half of the chemical to be degraded.) >> >> What in this context would be the mechanism for the degredation of Be? It >is not >> radioactive. >> -- >> John D Dalton Hi Jane, I think the EPA paper where this statement is from, was including beryllium compounds as well as different forms of Be in their assessment. Bob J is on holidays, but sends this: USGS DATA: Beryllium Beryllium has only one isotope, 9Be, on earth. Cosmogenic Be is produced in the atmosphere by cosmic ray spallation of oxygen and nitrogen (Arnold and Al-Salih, 1955; Peters, 1955, 1959). Because beryllium tends to exist in solution at pH levels less than about 5.5 , it will enter into solution and be transported to the Earth's surface via rainwater. As the precipitation quickly becomes more alkaline, Be drops out of solution. Cosmogenic 10Be thereby accumulates at the soil surface, where its logn half-life (1.6 Ma) permits a long residence time before decaying to 10Be. 10Be and its daughter products have been used to examine soil erosion (Pavich et al., 1985; Brown et al., 1995), regolith soil formation (Barg et al., 1992), the development of lateritic soils (Bernat et al., 1992). Concentrations of 7Be and 10Be have been measured in precipitation (Domink et al., 1987; Brown et al., 1989; Brown et al., 1992; Knies et al., 1994), atmospheric aerosols (Dibb et al., 1994), and river waters and associated sediments (Brown et al., 1992, 1995). The atmospheric flux of cosmogenic 7Be (half-life = 53 days) has been measured to determine erosion rates and fluvial transport mechanisms (Dominik et al., 1987), as well as to determine direct contribution of rainfall to terrestrial waters (e.g. streamwater; Cooper et al., 1991). To our knowledge, no studies have reported beryllium isotopes in ground-water samples. While beryllium isotopes may prove analytically difficult because of its low concentrations in catchment waters, and because interpretations would require close consideration of sorption versus solution behavior, the substatial differences in nuclide contents between important catchment compartments may make Be istopes worth examining (Nimz, 1998). References: Arnold, J. R., and Al-Salih, H. A. (1955). "Beryllium-7 produced by cosmic rays". Science, 121: 451-453. Barg, E., Lai, D., Jull, A. J. T., Southon, J., Caffee, M. W., Finkel, R. C., and Pavich, M. (1992). "Applications of cosmogenic nuclear methods for studying soil erosion and formation rates." In: Y. K. Kharaka and A. S. Maest (Eds.), Water-Rock Interaction, Proceedings of the 7th International Symposium on Water-Rock Interaction. Balkema Publishers, Rotterdam, p. 541. Bernat, M., Bokilo, J. E., Yiou, F., Raisbeck, G. M., and Muller, J-P. (1990). "10Be and natural isotopes of U and Th in a laterlite cover from Camaroon." Chem. Geol., 84: 347. Brown, L., Stensland, G. J., Klein, J. and Middleton, R. (1989). "Atmospheric deposition of 7Be and 10Be." Geochim. et Cosmochim. Acta, 53: 135. Brown, E. T, Edmond, J. M., Raisbeck, G. M., Bourles, D. L., Yiou, F. and Measures, C. I. (1992). "Beryllium isotope geochemistry in tropical river basins." Geochim. et Cosmochim. Acta, 56: 1607. Brown, E. T., Stallard, R. F., Laren, M. C., Raisbeck, G. M., and Yiou, F. (1995). "Denudation rates determined from the accumulation of in-situ produced 10Be in the Luquillo experimental forest, Puerto Rico." Earth Planet. Sci. Lett., 129: 193. Cooper, L. W., Olsen, C. R., Solomon, D. K., Larsen, I. L., Cook, R. B., and Grebmeier, J. M. (1991). "Stable Isotopes of Oxygen and Natural Fallout Radionuclides Used for Tracing Runoff During Snowmelt in an Arctic Watershed". Water Resour. Res., 27, 9: 2171- 2179. Dibb, J. E., Meeker, L. D., Finkel, R. C., Southon, J. R., Caffee, M. W., and Barrie, L. A. (1994). "Estimation of stratospheric input to the Arctic troposphere: 7Be and 10Be in aerosols at Alert." Canada J. Geophys. Res., 99: 12855. Domink, J., Burrus, D. and Vernet, J-P. (1987). "Transport of environmental radionuclides in an alpine watershed." Earth Planet. Sci. Lett., 84: 165. Faure, G. (1986). Principles of Isotope Geology, Second Edition. John Wiley & Sons, New York. pp. 589. Knies, D. L., Elmore, D., Sharma, P., Vogt, S., Li, R., Lipshutz, M. E., Petty, G., Ferrel, J., Monagham, M. C., Fritz, S., and Agee, E. (1994). "7Be, 10Be, and 36Cl in precipitation." Nucl. Instr. Meth. Phys. Res., 92: 340. Nimz, G. J. (1998). "Lithogenic and Cosmogenic Tracers in Catchment Hydrology." In: C. Kendall and J. J. McDonnell (Eds.), Isotope Tracers in Catchment Hydrology. Elsevier, pp. 247-290. Pavich, M. J., Brown, L., Valette-Silver, J. N., Klein, J. and Middleton, R. (1985). "10Be analysis of a Quaternary weathering profile in the Virginia Peidmont." Geology, 13: 39. Peters, B. (1955). "Radioactive beryllium in the atmosphere and on earth". Proc. Indian Acad. Sci, Sect. A, 41, 67-71. Peters, B. (1959). "Cosmic-ray produced radioactive isotopes as tracers for studying large-scale atmospheric circulation", J. Atmos. Terr. Phys., 13, 351-370.