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

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Calculation of D values Note that rates are calculated later as D f. Calculation of fugacities f W = [E W + f I(D I + D X) + f A(D V + D Q + D C + D M)] /[D V + D W + D J + D Y + (D D + D T)(D S + D B)/(D R + D T + D S + D B)] = [1.0 + 10 –3 (320 + 32) + 10 –4 (400 + 2.5 + 5 + 0.08)] /[400 + 80 + 320 + 16 + (480 + 40)(60 + 60)/(120 + 40 + 60 + 60)] = (1.0 + 0.352 + 0.041)/(400 + 80 + 320 + 16 + 223) = 1.393/1039 = 0.00134 Pa f S = f W(D D +D T)/(D R + D T + D S + D B) = 0.00134(480 + 40)/(120 + 40+ 60 + 60) = 0.00134 ¥ 520/280 = 0.00249 Pa Concentrations C W = Z Wf W = 0.00107 mol/m 3 = 0.27 g/m 3 (dissolved only) C S = Z Sf S = 1.49 mol/m 3 = 373 g/m 3 ©2001 CRC Press LLC Rates (mol/h) D B = G BZ S = 0.1 ¥ 600 = 60 0.149 f S D R = G RZ S = 0.2 ¥ 600 = 120 0.300 f S Multiplying Fugacity DT = GTZW = 50 ¥ 0.8 = 40 0.100 fS (sediment to water) 0.054 fW (water to sediment) DD = GDZP = 0.3 ¥ 1600 = 480 0.643 fW DW = VWZWkW = 106 ¥ 0.8 ¥ 10 –4 = 80 0.107 fW (water phase only, not on particles) DV = GVZW = 500 ¥ 0.8 = 400 0.536 fW (evaporation) 0.040 fA (absorption) DJ = GJZW = 400 ¥ 0.8 = 320 0.429 fW D Y = G YZ P = 0.01 ¥ 1600 = 16 0.021 f W D M = G MZ W = 0.1 ¥ 0.8 = 0.08 8 ¥ 10 –6 f A D C = G CZ Q = 0.001 ¥ 5000 = 5 5 ¥ 10 –4 f A D Q = G QZ Q = 0.0005 ¥ 5000 = 2.5 2.5 ¥ 10 –4 f A D I = G IZ W = 400 ¥ 0.8 = 320 0.320 f I D X = G XZ P = 0.02 ¥ 1600 = 32 0.032 f I D S = V SZ Sk S = 10 4 ¥ 600 ¥ 10 –5 = 60 0.149 f S E W = 1.0 f I = 10 –3 f A = 10 –4
C F ª Z Ff W ª 1.608 mol/m 3 ª 402 g/m 3 (fish) C B ª Z Ff S ª 2.988 mol/m 3 ª 747 g/m 3 (benthos) Total Amounts Water V WZ Wf W = 1072 mol (dissolved only) Particles V PZ Pf W = 54 mol Sediment V SZ Sf S = 14940 mol Total = 16070 mol Residence Times Total input to water is 1.393 mol/h from emissions, advective inflow and the atmosphere and 0.4 mol/h from sediment. Total input from sediment is by deposition and diffusion from water. Water (1072 + 54)/(1.393 + 0.4) = 628 h or 26 days Sediment 14940/(0.643 + 0.054) = 21400 h or 893 days Total 16070/1.393 = 11540 h or 481 days ©2001 CRC Press LLC (does not include fish or benthos which are probably negligible) Total inputs to and outputs from both water and sediment and the entire system balance within round-off error. This example, while tedious to do by hand, is readily implemented on a spreadsheet, or the software available on the internet can be used. It gives a clear quantification of all the fluxes and demonstrates which processes are most important. A mass balance diagram such as Figure 8.6 illustrates the process rates clearly. 8.7 QWASI MODEL OF CHEMICAL FATE IN RIVERS The QWASI lake equations can be modified to describe chemical fate in rivers by one of two methods. The river can be treated as a series of connected lakes or reaches, each of which is assumed to be well mixed, with unique water and sediment concentrations. There can be varying discharges into each reach, and tributaries can be introduced as desired. The larger the number of reaches, the more closely simulated is the true “plug flow” condition of the river. Figure 8.7 illustrates the approach. The second approach is to set up and solve the Lagrangian differential equation for water concentration as a function of river length, as was discussed when comparing Eulerian and Lagrangian approaches in Chapter 2. This has been discussed
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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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and Therefore, ©2001 CRC Press LLC
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eaction situation in which there is
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The rate constants in each case are
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©2001 CRC Press LLC 1/t O = SD Ai/
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e achieved in 10 days. Detractors o
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sulfate to sulfide or by dechlorina
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to Zepp and Cline (1977) for the or
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©2001 CRC Press LLC 6.7 LEVEL II C
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Figure 6.3 Fugacity Level II calcul
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McKay, Donald. "Intermedia Transpor
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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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Page 183 and 184: Figure 7.8 Movement of air phase (k
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Page 187 and 188: Figure 7.9 Combination of D values
Page 189 and 190: Figure 7.10 Four-compartment Level
Page 191 and 192: Table 7.2 Order of Magnitude Values
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Page 195 and 196: Figure 7.12 Sample Level III output
Page 197 and 198: McKay, Donald. "Applications of Fug
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Page 203 and 204: LEVEL1B A six-compartment Level I p
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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
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Page 227 and 228: Figure 8.10 Fish bioaccumulation pr
Page 229 and 230: The nature of the processes control
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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
Page 241 and 242: mated again in mg/day. Food, the ot
Page 243 and 244: models. Most interest is in LRT in
Page 245 and 246: available from the University of To
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