McKay, Donald. "Front matter" Multimedia Environmental Models ...

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K QA thus can be calculated by the analogous equation, ©2001 CRC Press LLC K QA = yK OA(r/1000) where y is organic matter mass fraction. This is equivalent to Z Q = yZ O (r/1000), where Z O is the chemical’s Z value in octanol and r is the aerosol density. In summary, Z Q can be deduced using the above equation, using the simple oneparameter expression for K QA or one of the two-parameter equations for K P. Bidleman and Harner (2000) discuss the merits of these approaches in more detail. 5.5.6 Other Partition Coefficients In principle, partition coefficients can be defined and correlated for any phase of environmental interest, usually with respect to the fluid media air or water. For example, vegetation or foliage-air partition coefficients K FA can be measured and correlated against K OA. Since K FA is Z F/Z A and K OA is Z O/Z A, the correlation is essentially of Z F versus Z O. Hiatt (1999) has suggested that, for foliage, K FA is approximately 0.01 K OA, implying that Z F is about 0.01 Z O, or foliage has a content of octanol-equivalent material of 1%. It is thus possible to estimate Z values for chemicals in any phase of environmental interest, provided that the appropriate partition coefficient has been measured or can be estimated. Figure 5.5 summarizes the relationships between fugacity, concentrations, partition coefficients, and Z values. 5.6 MULTIMEDIA PARTITIONING CALCULATIONS 5.6.1 The Partition Coefficient Method The calculation of one phase concentration from another by the use of a simple partition coefficient is the most direct and convenient method. Care must be taken that the concentration units and the partition coefficient dimensions are consistent, especially when dealing with solid phases. There may also be inadvertent inversion of a partition coefficient, i.e., the use of K 12 instead of K 21. It is also possible to deduce certain partition coefficients from others; e.g., if an air/water and a soil/water partition coefficient are available, then the air/soil or soil/air partition coefficient can be deduced as follows: K AS = K AW/K SW If we are treating 10 phases, then it is possible to define 9 independent interphase partition coefficients, the 10th being dependent on the other 9. In principle, with 10 phases, it is possible to define 90 partition coefficients, half of which are reciprocals of the others. When dealing with very complex multicompartment envi-
Compartment Definition of Fugacity Capacities Definition of Z (mol/m3 Pa) Air 1/RT R = 8.314 Pa m3 /mol K T = temp. (K) Water 1/H or CS /PS CS = aqueous solubility (mol/m3 ) PS = vapor pressure (Pa) H = Henry’s law constant (Pa m3 /mol) Solid sorbent (e.g., soil, sediment, particles) KPrS/H KP = partition coeff. (L/kg) rS = density (kg/L) Biota KBrS/H KB = bioconcentration factor (L/kg) rB = density (kg/L) Pure solute 1/PSv v = solute molar volume (m3 /mol) Figure 5.5 Relationships between Z values and partition coefficients and summary of Z value definitions. ronmental media, extreme care must be taken to avoid over- or underspecifying partition coefficients and to ensure that the ratios are not inverted. We have developed the capability of performing our first multimedia partitioning calculations. If we have a series of phases of volume V 1, V 2, V 3, and V 4, and we know the partition coefficients K 12, K 13, K 14, and we introduce a known amount of ©2001 CRC Press LLC
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McKay, Donald. "Front matter" Multi
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Multimedia Environmental Models The
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hensive, and reliable, and they hav
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Chapter 1 Introduction Chapter 2 So
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McKay, Donald. "Introduction" Multi
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It is now evident that our task is
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McKay, Donald. "Some Basic Concepts
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give the derived units directly wit
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Energy (joule, J) The joule, which
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particles (aerosols), or biota in w
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Worked Example 2.1 A three-phase sy
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(i) What is the concentration (C) i
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Answer ©2001 CRC Press LLC 5.1 kg,
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or or When t is zero, C is zero, th
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What is the absolute minimum piscic
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©2001 CRC Press LLC C 1 = C O/(1 +
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containing nonequilibrium quantitie
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1. Fallout of chemical from air to
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validated using real environments.
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©2001 CRC Press LLC CHAPTER 3 Envi
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of other, somewhat similar or homol
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Table 3.2 List of Chemicals Commonl
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elatively high concentrations. This
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exists between toxicologists and ch
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determine priority. This is a subje
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Another important classification of
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Figure 3.1 (continued) ©2001 CRC P
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Table 3.5 (continued) dichlorometha
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Table 3.5 (continued) total PCB 326
Page 59 and 60: Figure 3.2 Plot of log K AW vs. log
Page 61 and 62: chlorofluoro compounds are very sta
Page 63 and 64: 3.3.2.7 Arsenic Compounds Arsenic,
Page 65 and 66: McKay, Donald. "The Nature of Envir
Page 67 and 68: Figure 4.1 Evaluative environments.
Page 69 and 70: are subject to two important deposi
Page 71 and 72: metals and organic chemicals from w
Page 73 and 74: carbon figure for deeper sediments
Page 75 and 76: flows. The quality of this groundwa
Page 77 and 78: Table 4.2 Evaluative Environments A
Page 79 and 80: McKay, Donald. "Phase Equilibrium"
Page 81 and 82: Figure 5.1 Some principles and conc
Page 83 and 84: likely using an equilibrium criteri
Page 85 and 86: Another useful quantity is the rati
Page 87 and 88: experimentally, but not directly, u
Page 89 and 90: ©2001 CRC Press LLC 5.3 PROPERTIES
Page 91 and 92: 1.0. This, then, is the fugacity or
Page 93 and 94: where ©2001 CRC Press LLC pH is -l
Page 95 and 96: In terms of solubilities, S iA and
Page 97 and 98: The temperature coefficient is the
Page 99 and 100: (1982), Baum (1997) and Leo (2000).
Page 101 and 102: Although it may appear environmenta
Page 103 and 104: Figure 5.4 Illustration of quantita
Page 105 and 106: 5.5 ENVIRONMENTAL PARTITION COEFFIC
Page 107 and 108: C S = K PC W benzene = 1.1 ¥ 0.001
Page 109: Mackay (1986), in an attempt to sim
Page 113 and 114: high concentration in the fish, but
Page 115 and 116: heat capacity of 0.38 J/g°C requir
Page 117 and 118: Therefore, ©2001 CRC Press LLC f =
Page 119 and 120: ©2001 CRC Press LLC Z T = S(V i/V
Page 121 and 122: ©2001 CRC Press LLC air Z = P S /R
Page 123 and 124: Table 5.1 Table 5.1 Summary of Defi
Page 125 and 126: Figure 5.7 Fugacity form 1 for dedu
Page 127 and 128: Calculate the following physical-ch
Page 129 and 130: ©2001 CRC Press LLC CHAPTER 6 Adve
Page 131 and 132: that all water will spend 100 days
Page 133 and 134: This enables us to conceive of, and
Page 135 and 136: ©2001 CRC Press LLC f = 15/0.5 = 3
Page 137 and 138: D AS dominates. A residence time of
Page 139 and 140: and Therefore, ©2001 CRC Press LLC
Page 141 and 142: eaction situation in which there is
Page 143 and 144: The rate constants in each case are
Page 145 and 146: ©2001 CRC Press LLC 1/t O = SD Ai/
Page 147 and 148: e achieved in 10 days. Detractors o
Page 149 and 150: sulfate to sulfide or by dechlorina
Page 151 and 152: to Zepp and Cline (1977) for the or
Page 153 and 154: ©2001 CRC Press LLC 6.7 LEVEL II C
Page 155 and 156: Figure 6.3 Fugacity Level II calcul
Page 157 and 158: McKay, Donald. "Intermedia Transpor
Page 159 and 160: Figure 7.1 Illustration of nonequil
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5. Diffusion within soils, and from
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sionally, the term flux rate is use
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©2001 CRC Press LLC N = ABDC/ Dy m
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no currents or eddies. In practice,
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diffusivity, and some unknown layer
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where ©2001 CRC Press LLC X = y/ U
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fraction of the total volume that i
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Figure 7.6 Mass transfer at the int
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partition coefficient. The signific
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and the series retains a similar ra
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ments of resuspension rates are par
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Figure 7.8 Movement of air phase (k
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ates can thus be used to estimate m
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Figure 7.9 Combination of D values
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Figure 7.10 Four-compartment Level
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Table 7.2 Order of Magnitude Values
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Unlike the Level II calculation, it
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Figure 7.12 Sample Level III output
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McKay, Donald. "Applications of Fug
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applications. Citations are given t
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Another approach is to employ Monte
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LEVEL1B A six-compartment Level I p
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Figure 8.1 Air-water exchange proce
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The total rates of transfer are thu
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Figure 8.2 Chemical transport and t
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mean. For chemical between depths o
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8.5.2 Process Description The water
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learn the benefits of using fugacit
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where Figure 8.5 QWASI model: stead
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are similar to those described by M
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C F ª Z Ff W ª 1.608 mol/m 3 ª 4
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y Mackay et al. (1983), and an appl
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accordingly, but the final solution
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Figure 8.10 Fish bioaccumulation pr
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The nature of the processes control
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iomagnification is more significant
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An alternative and more elegant met
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8.11.2 Model of a Chemical Evaporat
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Paterson et al. (1991), and Hung an
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8.14.1 Introduction ©2001 CRC Pres
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mated again in mg/day. Food, the ot
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models. Most interest is in LRT in
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available from the University of To
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McKay, Donald. "Appendix" Multimedi
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©2001 CRC Press LLC
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