UNDERSTANDING VARIATION IN PARTITION COEFFICIENT, Kd ...

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effect on lead adsorption have been established by Gerritse et al. (1982) and Soldatini et al. (1976). Lead adsorption by a subsurface soil sample from Hanford, Washington was investigated by Rhoads et al. (1992). Adsorption data from these experiments showed that K d values increased with decreasing lead concentrations in solution (from 0.2 mg/l to 0.0062 mg/l). 5.5.6.2 K d Look-Up Tables Among all available data, Gerritse et al (1982) obtained adsorption data at lead concentrations (0.0001 - 0.01 mg/l) which apparently precluded precipitation reactions. Also, these concentrations are within the range of lead concentrations most frequently encountered in ground waters (Chow, 1978). Additionally, data obtained by Rhoads et al. (1992) indicated that K d values vary log-linearly as a function of equilibrium lead concentrations within the range of 0.00001 to 0.2 mg/l. The data generated by Gerritse et al. (1982) and Rhoads et al. (1992) were used to develop a look-up table (Table 5.9) of K d as a function of soil pH and equilibrium lead concentrations. 5.5.6.2.1 Limits of K d Values with Respect to pH The pH ranges in the look-up table (Table 5.9) were selected from the rate of change that we noted in the K d data as a function of pH. The K d values within this pH range increase with increasing pH, and are greatest at the maximum pH limit (pH.11) of soils. Table 5.9. Estimated range of K d values for lead as a function of soil pH, and equilibrium lead concentrations. Equilibrium Lead Concentration (µg/l) K d (ml/g) 0.1 - 0.9 1.0 - 9.9 10 - 99.9 100 - 200 5.33 Soil pH 4.0 - 6.3 6.4 - 8.7 8.8 - 11.0 Minimum 940 4,360 11,520 Maximum 8,650 23,270 44,580 Minimum 420 1,950 5,160 Maximum 4,000 10,760 20,620 Minimum 190 900 2,380 Maximum 1,850 4,970 9,530 Minimum 150 710 1,880 Maximum 860 2,300 4,410
5.5.6.2.2 Limits of K d Values with Respect to Equilibrium Lead Concentrations The limits of equilibrium lead concentrations (0.0001 mg/l to about 0.2 mg/l) were selected based on the experimental data generated by Gerritse et al. (1982) and Rhoads et al. (1992). These investigators showed that within the range of initial lead concentrations used in their experiments the principal lead removal reaction from solution was adsorption and not precipitation. Four concentration ranges were selected to develop the K d values. 5.6 Plutonium Geochemistry and K d Values 5.6.1 Overview: Important Aqueous- and Solid-Phase Parameters Controlling Retardation In the ranges of pH and conditions typically encountered in the environment, plutonium can exist in all 4 oxidation states, namely +3, 4, +5, and +6. Under oxidizing conditions, Pu(IV), Pu(V), and Pu(VI) are common, whereas, under reducing conditions, Pu(III) and Pu(IV) would exist. Dissolved plutonium forms very strong hydroxy-carbonate mixed ligand complexes, therefore, its adsorption and mobility is strongly affected by these complex species. Under conditions of low pH and high concentrations of dissolved organic carbon, it appears that plutonium-organic complexes may be control adsorption and mobility of plutonium in the environment. If plutonium is present as a distinct solid phase (amorphous or partly crystalline PuO 2@xH 2O) or as a solid solution, the upper limits of aqueous plutonium concentrations would be in the 10 -12 to 10 -9 M range. Dissolved plutonium in the environment is typically present at #10 -15 M levels indicating that adsorption may be the principal phenomenon that regulates the mobility of this actinide. Plutonium can adsorb on geologic material from low to extremely high affinities with K d values ranging from 11 to 300,000 ml/g. Plutonium in the higher oxidation state adsorbed on iron oxide surfaces may be reduced to the tetravalent state by Fe(II) present in the iron oxides. Two factors that influence the mobilization of adsorbed plutonium under environmental pH conditions (>7) are the concentrations of dissolved carbonate and hydroxyl ions. Both these ligands form very strong mixed ligand complexes with plutonium, resulting in desorption and increased mobility in the environment. 5.6.2 General Geochemistry Plutonium is produced by fissioning uranium fuel and is used in the construction of nuclear weapons. Plutonium has entered the environment either through accidental releases or through disposal of wastes generated during fuel processing and the production and detonation of nuclear weapons. Plutonium has 15 isotopes, but only 4 of these isotopes namely, 238 Pu [t ½ (half life) = 5.34
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United States Office of Air and Rad
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NOTICE The following two-volume rep
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This publication is the result of a
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TO COMMENT ON THIS GUIDE OR PROVIDE
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CONTENTS NOTICE ...................
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Concentrations Extractable Iron Con
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Appendix A - Acronyms and Abbreviat
Page 15 and 16: Figure E.1. Variation of K d for Cr
Page 17 and 18: Table 5.16. Uranium(VI) aqueous spe
Page 19 and 20: Table H.3. Simple and multiple regr
Page 21 and 22: 1.0 Introduction The objective of t
Page 23 and 24: discussed. The geochemical modeling
Page 25 and 26: 2.0 The K d Model The simplest and
Page 27 and 28: track many more parameters and some
Page 29 and 30: of interest. The retardation factor
Page 31 and 32: (e.g., soil). An increasing body of
Page 33 and 34: complexation constants for the cont
Page 35 and 36: the soil column. Additionally, the
Page 37 and 38: Element Table 5.2. Concentrations o
Page 39 and 40: 5.2.3 Aqueous Speciation Cadmium fo
Page 41 and 42: 5.2.4 Dissolution/Precipitation/Cop
Page 43 and 44: cadmium, indicating that cadmium an
Page 45 and 46: 5.2.6.2.2 Limits of K d Values with
Page 49 and 50: organic chelates (e.g., EDTA). Init
Page 53 and 54: (tarapacaite) in chromium sludge fr
Page 55 and 56: K d). Soils containing Mn oxides ox
Page 57 and 58: Table 5.7. Estimated range of Kd va
Page 59 and 60: most common valence state of lead e
Page 61 and 62: Table 5.8. Lead aqueous species inc
Page 63 and 64: Under reducing conditions, galena (
Page 65: C Adsorption of lead increases with
Page 69 and 70: (Choppin, 1983). Plutonium hydrolyt
Page 71 and 72: Table 5.10. Plutonium aqueous speci
Page 73 and 74: 5.6.5 Sorption/Desorption Plutonium
Page 75 and 76: content in the system. Additionally
Page 81 and 82: much greater concentrations. Thus,
Page 83 and 84: exchanged which they attributed to
Page 85 and 86: up tables was based in part on thei
Page 87 and 88: organic complexes likely predominat
Page 89 and 90: Thorium undergoes hydrolysis in aqu
Page 91 and 92: The distribution of thorium aqueous
Page 93 and 94: from about 10 -8.5 mol/l (0.0007 mg
Page 95 and 96: Based on the assumptions and limita
Page 97 and 98: 5.10 Tritium Geochemistry And K d V
Page 99 and 100: uranium. Uranium(VI) species domina
Page 101 and 102: gives 0.1 to 10 µg/l as the range
Page 103 and 104: mineral in reducing ore zones (Fron
Page 105 and 106: Percent Distribution 100 80 60 40 2
Page 107 and 108: 5.11.6 Partition Coefficient, K d ,
Page 109 and 110: No attempt was made to statisticall
Page 111 and 112: Table 5.18. Selected chemical and t
Page 113 and 114: Another objective of this report is
Page 115 and 116: 6.0 REFERENCES Adriano, D. C. 1992.
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Bensen, D. W. 1960. Review of Soil
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Metals by Geomedia. Variables, Mech
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EPA (U.S. Environmental Protection
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Griffin, R. A., A. K. Au, and R. R.
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+ Keeney-Kennicutt, W. L., and J. W
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Mattigod, S. V., A. L. Page, and I.
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Oscarson, D. W., and H. B. Hume. 19
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Relyea, J. F. and D. A. Brown. 1978
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Schultz, R. K., R. Overstreet, and
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Szalay, A. 1964. “Cation Exchange
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Yariv, S., and H. Cross. 1979. Geoc
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APPENDIX A Acronyms, Abbreviations,
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PC Personal computers operating und
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A.3.0 List of Symbols and Notation
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APPENDIX B Definitions
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Clay Content - particle size fracti
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Polynuclear Species - an aqueous sp
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C.1.0 Background Appendix C Partiti
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Cadmium K d Table C.2. Correlation
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C.3.0 Data Set for Soils Table C.4
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Cd K d (ml/g) Clay Cont. (wt%) pH C
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D.1.0 Background Appendix D Partiti
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A second data set (see Section D.4)
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Table D.3. Correlation coefficients
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By transposing the CEC and cesium K
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Table D.6. Cesium K d values measur
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eported in Table D.8 are described
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a 1 b 1 Range of Solution Cs Concen
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Figure D.4. Generalized cesium Freu
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Table D.10. Estimated range of K d
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D.3.0 K d Data Set for Soils and Pu
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Cesium Kd (ml/g) Clay (wt.% ) Mica
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Cesium K d (ml/g) Clay (wt%) Mica (
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Bruggenwert, M. G. M., and A. Kamph
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Shiao, S. Y., P. Rafferty, R. E. Me
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E.1.0 Background Appendix E Partiti
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chromium-reductive soils may stem f
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E.2.0 Approach The approach used to
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Table E.3. Estimated range of K d v
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Table E.4. Data from Rai et al. (19
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E.4.0 References Davis, J. A. and J
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APPENDIX F Partition Coefficients F
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(CEC) of the soils. Such an anomaly
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Table F.1. Summary of K d values fo
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Figure F.2. Variation of K d as a f
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F.4.0 References Abd-Elfattah, A.,
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APPENDIX G Partition Coefficients F
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A number of investigators have exam
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pH value, which is typical of the m
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These significant reductions in ads
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This is typically accomplished by t
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The scatterplots are typically disp
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Table G.2. Regression models for pl
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G.4.0 References Barney, G. S. 1984
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Nelson, D. M., R. P. Larson, and W.
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APPENDIX H Partition Coefficients F
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1.6 ml/g for a measurement made on
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Figure H.1. Relation between stront
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Figure H.2. Relation between stront
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H.2.4 Approach Figure H.4. Relation
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A second look-up table (Table H.5)
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Sr K d (ml/g) Clay Content (%) pH C
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Sr K d (ml/g) Clay Content (%) pH C
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Sr K d (ml/g) Clay Conten t (%) pH
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Konishi, M., K. Yamamoto, T. Yanagi
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APPENDIX I Partition Coefficients F
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descriptive statistics of the thori
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Figure I.1. Linear regression betwe
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The look-up table (Table I.5) for t
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Thorium K d (ml/g) pH Clay (wt.%) C
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Rai, D., A. R. Felmy, D. A. Moore,
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J.1.0 Background Appendix J Partiti
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J.2.2 Uranium K d Studies on Soils
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Washington. The studies included an
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and then decreases with increasing
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Kd (ml/g) 100,000 10,000 1,000 100
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papers. Warnecke et al. (1984) indi
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Anderson et al. (1982) summarize an
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McKinley and Scholtis (1993) compar
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In a similar comparison of sorption
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J.3.1 K d Values as a Function ff p
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discussed, and one would have to ma
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al., 1992; and others). These refer
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· Manskaya et al. (1956) studied a
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concentrations of humic acid, there
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pH U Kd (ml/g) Clay Cont. (wt.%) CE
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J.6.0 References Ames, L. L., J. E.
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Erikson, R. L., C. J. Hostetler, R.
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R. C. Ewing. Materials Research Soc
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Sheppard, M. I., and D. H. Thibault
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Yamamoto, T., E. Yunoki, M. Yamakaw
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