Uranium concentrations in groundwater

An Evaluation of Solubility Limits on Maximum Uranium Concentrations in Groundwater... 

Solubility phenomena between solid and aqueous phases are treated in the chapters Leaching from cementitious materials used in radioactive waste disposal sites by Kosuke Yokozeki, An evaluation of solubility limits on maximum uranium concentrations in groundwater by Teruki Iwatsuki and Randolf C. Arthur, and The solubility of hydroxyaluminosilicates and the biological availability of aluminium by Christopher Exley. 

An Evaluation of Solubility Limits on Maximum Uranium Concentrations in Groundwater by Teruki Iwatsuki and Randolf C. Arthur. Email iwatsuki.teruki jaea.go.jp... 

High concentrations of selenium may occur in groundwater in semiarid or arid areas, near known mineral deposits containing sulfide minerals of uranium and vanadium. Irrigated agriculture may substantially increase concentrations in groundwater in areas with high selenium levels in soil. 

Unauthorized landfill disposal of uranium processing wastes (e.g., Shpack Landfill in Norton, Massachusetts, and the Middlesex Municipal Landfill in Middlesex, New Jersey) has resulted in soil contamination (Bechtel National 1984 Cottrell et al. 1981). Also, elevated uranium concentrations have been measured in soil samples collected at 30 of 51 hazardous waste sites and in sediment samples at 16 of 51 hazardous waste sites (HazDat 1998). The HazDat data includes both Superfund and NPL sites. Elevated concentrations of uranium have been detected in soil, in surface water, in groundwater, or in all three of these environmental media from these sites. In several cases, the uranium concentrations in soils were significantly elevated. For example, uranium concentrations from the Shpack/ALI site were found to be 16,460 pCi/g (24,000 pg/g). At the United States Radium Corporation site (New Jersey), uranium concentrahons ranged from 90 to 12,000 pCi/g (130-18,000 pg/g) for the Monticello site (Utah), uranium levels were reported to range from 1 to 24,000 pCi/g (1.5-36,000 pg/g) (HazDat 1998). 

Uranous ion (U ) and its aqueous complexes predominate in groundwaters of low Eh. U(IV) is the major oxidation state in the most common uranium ore minerals uraninite [U02(c)]—pitchblende is roughly U02(am)—and coffinite (USi04). The U(IV) concentrations in groundwater at low... 

The total daily ingestion of uranium can vary markedly due to the local concentration in drinking water or the consumption of mineral waters. The range of uranium concentrations in potable surface waters is 0.03-15 p,g/liter (0.4-185 mBq/liter) [19], and while public groundwater supplies are generally <10 JLg/liter (<125 mBq/liter), a few exceed 10(X) p,g/liter [20]. Because of the extreme variability in uranium concentration in potable waters, no global average has been adopted by the United Nations Scientific Committee for the Effects of Atomic Radiation (UNSCEAR). Mineral waters in three European nations have been reported to contain 0.04-70 xg U/liter (0.5-870 mBq/liter) [21]. 

Natural systems that may be analogous in certain respects to a geologic repository for nuclear wastes provide a useful basis for testing assumptions, models and concepts used in repository performance assessments. The present study demonstrates that maximum U concentrations in groundwaters of the Tono Uranium Deposit appear to be limited by the solubility of the amorphous, hydrous oxide, U02(am). This conclusion, drawn from observations of a geologic system that has evolved over long periods of time, supports the... 

A comprehensive review of uranium determinations in sea water was given by Rogers and Adams. Ocean water contains uranium at a broadly uniform concentration (0.001-0.004 ppm). The average uranium concentration in stream water is less than 1 ppb U. Groundwater shows remarkable variability of concentration as a result of, for example, the presence of enriched mineralization, the time of contact of the water with the source rocks and the concentration of ligands that either form soluble uranium complexes or insoluble uranium compounds. 

No horizontal scale appears in Fig. 9 because the spacing between the axis of maximum uranium concentration in the groundwater and the axis of minimum uranium concentration as interpreted from the. samples is largely a function of the sample spacing. As the sample spacing is reduced, the apparent axes move closer together and the maximum and minimum uranium values become more extreme. The distance between the two interpreted axes may be as much as 5 km or less than... 

Anderson RF (1987) Redox behavior of uranium in an anoxic marine basin. Uranium 3 145-164 Anderson RF, Fleisher MQ, LeHuray AP (1989) Concentration, oxidation state, and particulate flux of uranium in the Black Sea. Geochim Cosmochim Acta 53 2215-2224 Back W, Hanshaw BB, Pyler TE, Plummer LN, Weiede AE (1979) Geochemical significance of groundwater discharge in Caleta Xel Ha, Quintana Roo, Mexico. Water Res 15 1521-1535 Barnes CE, Cochran JK (1990) Uranium removal in oceanic sediments and the oceanic U balance. Earth. Planet. Sci. Lett 97 94-101... 

The D-A model predicts the distribution of uranium and U-series isotopes across a bone section (Figs. 3 and 4). Under constant conditions Uranium is diffusing from the inner and outer surfaces of the bone, giving a u-shaped Uranium concentration profile that gradually flattens with time to a uniform uranium distribution when the bone reaches equilibrium with the uranium in the groundwater. Because the uranium is equilibrating with the outer portions of the bone section first, closed system U-series dates approach the true age of the bone towards the surfaces, but are underestimated towards the centre. Further details of the D-A model are given in the Appendix. 

According to the technology developer, geochemical fixation can treat dissolved hexavalent chromium and other metals in groundwater at concentrations ranging from the detection limit to several hundred parts per milhon. The developer asserts that geochemical attenuation can treat most of the common heavy metals, trace elements, and namral radionuclides that occur in groundwater, such as metal-cyanide complexes, arsenic, cadmium, chromium, copper, lead, selenium, uranium, and radium. 

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