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

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Table 7.1 Intermedia Transfer D Value Equation Compartments Process D Values air(1) – water(2) diffusion DV = 1/(1/kVAA12ZA + 1/kVWA12ZW) rain dissolution DRW2 = A12 UQ ZW ©2001 CRC Press LLC wet deposition D QW2 = A 12 U R Q v Q Z Q dry deposition D QD2 = A 12 U Q v Q Z Q D 12 = D V + D RW2 + D QD2 + D QW2 D 21 = D V air(1) – soil(3) diffusion DE =1/(1/kEAA13Z + Y3/(A13(BMAZA + BMWZW))) rain dissolution DRW3 = A13 UR vQZW wet deposition D QW3 = A 13 U R Q v Q Z Q dry deposition D QD3 = A 13 U Q v Q Z Q D 13 = D E + D RW3 + D QW3 + D QD3 D 31 = D E soil(3) – water(2) soil runoff D SW = A 13 U EW Z E water runoff D WW = A 13 U WW Z W sediment(4) – water(2) diffusion D32 = DSW + DWW D23 = 0 DY = 1/(1/kSWA24ZW + Y4/BW4A24ZW) deposition DDS = UDP A23 ZP reaction either bulk phase i or sum of all phases resuspension D RS = U RS A 23 Z S D 24 = D Y + D DS D 42 = D Y + D RS D Ri = k Ri V i Z i D Ri = S(k Rij V ij Z ij) advection bulk phase D Ai = G i Z i or U i A I Z i Aij is the horizontal area between media i and j. Subscripts on Z are A, water W, aerosol Q, soil E, sediments S and particles in water P. k VA = 3.6 + 5 U 10 1.2 m/h U10 in m/s k VW = 0.0036 + 0.01 U 10 1.2 m/h U10 in m/s These correlations will underestimate the mass transfer coefficients under turbulent conditions of breaking waves or in rivers where there is “white water.” Sedimentation rates can be estimated by assuming a deposition velocity of about 1 m/day. Therefore, a lake containing 15 g/m 3 of suspended solids is probably depositing 15 g/m 2 day of solids, which corresponds to about 10 cm 3 /m 2 day if the density is 1.5 g/cm 3 . This corresponds to 0.4 cm 3 /m 2 h or 40 ¥ 10 –8 m 3 /m 2 h or 40 ¥ 10 –8 m/h. Of this, a fraction is buried, and the remainder is resuspended. In waters of lower solids concentration, the deposition rate is correspondingly slower. The air-to-water D value (D 12) consists of diffusive absorption (D V) and nondiffusive wet and dry aerosol deposition. Each D value can be estimated and summed to give D 12.
Table 7.2 Order of Magnitude Values of Transport Parameters Parameter Symbol Suggested typical value Air side MTC over water kVA 3 m/h Water side MTC kVW 0.03 m/h Transfer rate to higher altitude US 0.01 m/h (90m/y) Rain rate (m3rain/m2area.h) UR 9.7 ¥ 10 –5 m/h (0.85m/y) Scavenging ratio Q 200000 Vol. fraction aerosols v Q 30 ¥ 10 –12 Dry deposition velocity UQ 10.8 m/h (0.003 m/s) Air side MTC over soil kEA 1 m/h Diffusion path length in soil Y3 0.05 m Molecular diffusivity in air BMA 0.04 m2 /h Molecular diffusivity in water BMW 4.0 ¥ 10 –6 m2 /h Water runoff rate from soil UWW 3.9 ¥ 10 –5 m/h (0.34 m/y) Solids runoff rate from soil UEW 2.3 ¥ 10 –8 m3 /m2h (0.0002 m/y) Water side MTC over sediment kSW 0.01 m/h Diffusion path length in sediment Y4 0.005 m Sediment deposition rate UDP 4.6 ¥ 10 –8 m3 /m2h (0.0004 m/y) Sediment resuspension rate URS 1.1 ¥ 10 –8 m3 /m2h (0.0001 m/y) Sediment burial rate UBS 3.4 ¥ 10 –8 m3 /m2h (0.0003 m/y) Leaching rate of water from soil to ground water UL 3.9 ¥ 10 –5 m3 /m2h (0.34 m/y) The water-to-air D value (D 21) is D V for diffusive volatilization and is, of course, the same D V as for absorption. The air-to-soil D value (D 13) is similar to D 12, but the areas differ, and the absorptionvolatilization D value is also different. The soil-to-air D value (D 31) is for volatilization. The water-to-sediment D value (D 24) represents diffusive transfer plus nondiffusive sediment deposition. The sediment-to-water D value (D 42) represents diffusive transfer plus nondiffusive resuspension. Finally, the soil-to-water D value (D 32) consists of nondiffusive water and particle runoff. There is no water-to-soil transfer, nor is there sediment-air exchange. The half-life for loss from a phase of volume V and Z value Z by process D is clearly 0.693 VZ/D. If a half-life t 1/2 is suggested, D is 0.693 VZ/t 1/2. Short halflives represent large D values and fast, important processes. It is always useful to calculate a half-life or a characteristic time VZ/D to ensure that it is reasonable. 7.10.2 Level III Equations We now write the mass balance equations for each medium as follows. ©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
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Figure 3.2 Plot of log K AW vs. log
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chlorofluoro compounds are very sta
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3.3.2.7 Arsenic Compounds Arsenic,
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McKay, Donald. "The Nature of Envir
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Figure 4.1 Evaluative environments.
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are subject to two important deposi
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metals and organic chemicals from w
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carbon figure for deeper sediments
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flows. The quality of this groundwa
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Table 4.2 Evaluative Environments A
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McKay, Donald. "Phase Equilibrium"
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Figure 5.1 Some principles and conc
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likely using an equilibrium criteri
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Another useful quantity is the rati
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experimentally, but not directly, u
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©2001 CRC Press LLC 5.3 PROPERTIES
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1.0. This, then, is the fugacity or
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where ©2001 CRC Press LLC pH is -l
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In terms of solubilities, S iA and
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The temperature coefficient is the
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(1982), Baum (1997) and Leo (2000).
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Although it may appear environmenta
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Figure 5.4 Illustration of quantita
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5.5 ENVIRONMENTAL PARTITION COEFFIC
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C S = K PC W benzene = 1.1 ¥ 0.001
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Mackay (1986), in an attempt to sim
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Compartment Definition of Fugacity
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high concentration in the fish, but
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heat capacity of 0.38 J/g°C requir
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Therefore, ©2001 CRC Press LLC f =
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©2001 CRC Press LLC Z T = S(V i/V
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©2001 CRC Press LLC air Z = P S /R
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Table 5.1 Table 5.1 Summary of Defi
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Figure 5.7 Fugacity form 1 for dedu
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Calculate the following physical-ch
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©2001 CRC Press LLC CHAPTER 6 Adve
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that all water will spend 100 days
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This enables us to conceive of, and
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©2001 CRC Press LLC f = 15/0.5 = 3
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D AS dominates. A residence time of
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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
Page 161 and 162: 5. Diffusion within soils, and from
Page 163 and 164: sionally, the term flux rate is use
Page 165 and 166: ©2001 CRC Press LLC N = ABDC/ Dy m
Page 167 and 168: no currents or eddies. In practice,
Page 169 and 170: diffusivity, and some unknown layer
Page 171 and 172: where ©2001 CRC Press LLC X = y/ U
Page 173 and 174: fraction of the total volume that i
Page 175 and 176: Figure 7.6 Mass transfer at the int
Page 177 and 178: partition coefficient. The signific
Page 179 and 180: and the series retains a similar ra
Page 181 and 182: ments of resuspension rates are par
Page 183 and 184: Figure 7.8 Movement of air phase (k
Page 185 and 186: ates can thus be used to estimate m
Page 187 and 188: Figure 7.9 Combination of D values
Page 189: Figure 7.10 Four-compartment Level
Page 193 and 194: Unlike the Level II calculation, it
Page 195 and 196: Figure 7.12 Sample Level III output
Page 197 and 198: McKay, Donald. "Applications of Fug
Page 199 and 200: applications. Citations are given t
Page 201 and 202: Another approach is to employ Monte
Page 203 and 204: LEVEL1B A six-compartment Level I p
Page 205 and 206: Figure 8.1 Air-water exchange proce
Page 207 and 208: The total rates of transfer are thu
Page 209 and 210: Figure 8.2 Chemical transport and t
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Page 213 and 214: 8.5.2 Process Description The water
Page 215 and 216: learn the benefits of using fugacit
Page 217 and 218: where Figure 8.5 QWASI model: stead
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Page 221 and 222: C F ª Z Ff W ª 1.608 mol/m 3 ª 4
Page 223 and 224: y Mackay et al. (1983), and an appl
Page 225 and 226: accordingly, but the final solution
Page 227 and 228: Figure 8.10 Fish bioaccumulation pr
Page 229 and 230: The nature of the processes control
Page 231 and 232: iomagnification is more significant
Page 233 and 234: An alternative and more elegant met
Page 235 and 236: 8.11.2 Model of a Chemical Evaporat
Page 237 and 238: Paterson et al. (1991), and Hung an
Page 239 and 240: 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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