UNDERSTANDING VARIATION IN PARTITION COEFFICIENT, Kd ...

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The look-up table (Table I.5) for thorium K d values was based on thorium concentrations and pH. These 2 parameters have an interrelated effect on thorium K d values. The maximum concentration of dissolved thorium may be controlled by the solubility of hydrous thorium oxides (Felmy et al., 1991; Rai et al., 1995; Ryan and Rai, 1987). The dissolution of hydrous thorium oxides may in turn vary with pH. Ryan and Rai (1987) reported that the solubility of hydrous thorium oxide is ~10 -8.5 to ~10 -9 in the pH range of 5 to 10. The concentration of dissolved thorium increases to ~10 -2.6 M (600 mg/L) as pH decreases from 5 to 3.2. Thus, 2 categories, pH 3 - 5 and pH 5 - 10, based on thorium solubility were included in the look-up table. Although precipitation is typically quantified by the solubility construct, a very large K d value was used in Table I.5 to describe high thorium concentrations. The following steps were taken to assign values to each category in the look-up table. For K d values in systems with pH values less than 8 and thorium concentrations less than the estimated solubility limits, Equation I.1 was used. This regression equation is for data collected between the pH range of 4 to 8 as shown in Figure I.1 [log (Th K d) = -0.13 + 0.69(pH)]. pH values of 4 and 6.5 were used to estimate the “pH 3 to 5” and “pH 5 to 8” categories, respectively. The K d values in the “pH 8 to 10” category were based on the single laboratory experiment conducted at pH 10 that had a K d of 200 ml/g. Upper and lower estimates of thorium K d values were calculated by adding or subtracting 1 logarithmic unit to the “central estimates” calculated above for each pH category (Figure I.2). The 1 logarithm unit estimates for the upper and lower limits are based on visual examination of the data in Figure I.1. The use of the upper and lower regression coefficient values at the 95 percent confidence limits (Table I.5) resulted in calculated ranges that were unrealistically large. At pH 4, for the “pH 3 to 5” category, the lower and upper log (Th K d) values were calculated to be 1 and 6.6, respectively; at pH 6.5, this range of K d was - 0.5 to 9.0). All thorium K d values for systems containing concentrations of dissolved thorium greater than their estimated solubility limit (10 -9 M for pH 5 to 10 and 10 -2.6 M for pH < 5) were assigned a K d of 300,000 ml/g. Table I.5. Look-up table for thorium K d values (ml/g) based on pH and dissolved thorium concentrations. [Tabulated values pertain to systems consisting of low ionic strength (
I.3.0 K d Data Set for Soils Figure I.2. Linear regression between thorium K d values and pH for the pH Range 4 to 8. [Values ±1 logarithmic unit from the regression line are also identified. The single K d value at pH 10 is identified by the filled circle)]. The data set of thorium K d values used to develop the look-up table are listed in Table I.6. I.8
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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
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Figure E.1. Variation of K d for Cr
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Table 5.16. Uranium(VI) aqueous spe
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Table H.3. Simple and multiple regr
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1.0 Introduction The objective of t
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discussed. The geochemical modeling
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2.0 The K d Model The simplest and
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track many more parameters and some
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of interest. The retardation factor
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(e.g., soil). An increasing body of
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complexation constants for the cont
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the soil column. Additionally, the
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Element Table 5.2. Concentrations o
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5.2.3 Aqueous Speciation Cadmium fo
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5.2.4 Dissolution/Precipitation/Cop
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cadmium, indicating that cadmium an
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5.2.6.2.2 Limits of K d Values with
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organic chelates (e.g., EDTA). Init
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(tarapacaite) in chromium sludge fr
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K d). Soils containing Mn oxides ox
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Table 5.7. Estimated range of Kd va
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most common valence state of lead e
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Table 5.8. Lead aqueous species inc
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Under reducing conditions, galena (
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C Adsorption of lead increases with
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(Choppin, 1983). Plutonium hydrolyt
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Table 5.10. Plutonium aqueous speci
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5.6.5 Sorption/Desorption Plutonium
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content in the system. Additionally
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much greater concentrations. Thus,
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exchanged which they attributed to
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up tables was based in part on thei
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organic complexes likely predominat
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Thorium undergoes hydrolysis in aqu
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The distribution of thorium aqueous
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from about 10 -8.5 mol/l (0.0007 mg
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Based on the assumptions and limita
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5.10 Tritium Geochemistry And K d V
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uranium. Uranium(VI) species domina
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gives 0.1 to 10 µg/l as the range
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mineral in reducing ore zones (Fron
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Percent Distribution 100 80 60 40 2
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5.11.6 Partition Coefficient, K d ,
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No attempt was made to statisticall
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Table 5.18. Selected chemical and t
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Another objective of this report is
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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.,
Page 222 and 223: APPENDIX G Partition Coefficients F
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Page 234 and 235: Table G.2. Regression models for pl
Page 236 and 237: G.4.0 References Barney, G. S. 1984
Page 238 and 239: Nelson, D. M., R. P. Larson, and W.
Page 240 and 241: APPENDIX H Partition Coefficients F
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Page 244 and 245: Figure H.1. Relation between stront
Page 246 and 247: Figure H.2. Relation between stront
Page 248 and 249: H.2.4 Approach Figure H.4. Relation
Page 250 and 251: A second look-up table (Table H.5)
Page 252 and 253: Sr K d (ml/g) Clay Content (%) pH C
Page 254 and 255: Sr K d (ml/g) Clay Content (%) pH C
Page 256 and 257: Sr K d (ml/g) Clay Conten t (%) pH
Page 264 and 265: Konishi, M., K. Yamamoto, T. Yanagi
Page 266 and 267: APPENDIX I Partition Coefficients F
Page 268 and 269: descriptive statistics of the thori
Page 270 and 271: Figure I.1. Linear regression betwe
Page 274 and 275: Thorium K d (ml/g) pH Clay (wt.%) C
Page 276 and 277: Rai, D., A. R. Felmy, D. A. Moore,
Page 278 and 279: J.1.0 Background Appendix J Partiti
Page 280 and 281: J.2.2 Uranium K d Studies on Soils
Page 282 and 283: Washington. The studies included an
Page 284 and 285: and then decreases with increasing
Page 286 and 287: Kd (ml/g) 100,000 10,000 1,000 100
Page 288 and 289: papers. Warnecke et al. (1984) indi
Page 290 and 291: Anderson et al. (1982) summarize an
Page 292 and 293: McKinley and Scholtis (1993) compar
Page 294 and 295: In a similar comparison of sorption
Page 296 and 297: J.3.1 K d Values as a Function ff p
Page 298 and 299: discussed, and one would have to ma
Page 300 and 301: al., 1992; and others). These refer
Page 302 and 303: · Manskaya et al. (1956) studied a
Page 304 and 305: concentrations of humic acid, there
Page 306 and 307: pH U Kd (ml/g) Clay Cont. (wt.%) CE
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pH U Kd (ml/g) Clay Cont. (wt.%) CE
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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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UNDERSTANDING VARIATION IN PARTITION COEFFICIENT, Kd ...

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