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

are similar to those described by Mackay (1989) for the fate of PCBs in Lake Ontario.
To obtain unsteady-state solutions requires programming the equations in Figure 8.5
or solving the differential equations by a numerical method.
Worked Example 8.1
For chemical X, determine for both water and sediment, the D values, total inputs
and outputs, fugacities at steady state, concentrations, total amounts, and residence
times. Also estimate the concentration of chemical X in fish and benthos.
Volumes
D values
Transport: For convenience, we express them as GZ, where G is an equivalent flow
m 3 /h. Refer to Table 8.3 for details.
Transformation: D = VZk
Inputs
Properties of Chemical X Z Values mol/m3 Pa
Molar mass = 250 g/mol ZA = 4 ¥ 10 –4
Vapor pressure = 0.5 Pa ZW = 0.8
Solubility = 100 g/m3 ZP = 1600
H = 1.25 Pa m3 /mol ZS = 600
log KOW = 4.47 ZF = 1200 (fish and benthos)
ZQ = 5000 (aerosol)
(as controlled by organic carbon and lipid contents)
©2001 CRC Press LLC
water k = 0.0001 h –1 (dissolved only) sediment = 0.00001 h –1
Emissions E W = 1 mol/h
Fugacities (derived from observed concentrations)
f A (air) = 10 –4 Pa
f I (input water) = 10 –3 Pa
water 106 m3 particles in water 25 m3 sediment 104 m3 GB = 0.1 GR = 0.2 GT = 50 GD = 0.3
GI = GJ = 400 GY = 0.01 GM = 0.1 GV = 500 (DV is GV ZW) GC = 0.001 GQ = 0.0005 GI = 400 GX = 0.02 (there is net sedimentation)