Soil/Sediment Inhalation
Equation 3 (non-radionuclides), equation 4 (radionuclides), and Table 3 present the exposure variables for the soil/sediment inhalation pathway for the residential, industrial, recreational, and agricultural scenarios. The particulate emission factor (PEF) is represented by the term that includes V, Um/Ut, F(x), Q/C, and CF3. The default PEF in SADA is 1.32E+9 (EPA 1996). The 1/VF term is only present if the contaminant is a volatile.
(3)
(4)
Table 3. Soil/Sediment Inhalation Parameters
Parameter
Units
Residential
Industrial
Recreational
Excavation
Agricultural
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Non-radionuclide chemical concentration in soil = Csn
mg/kg
Chemical-specific
Chemical-specific
Chemical-specific
Chemical-specific
Chemical-specific
Radionuclide chemical concentration in soil = Csr
pCi/g
Chemical-specific
Chemical-specific
Chemical-specific
Chemical-specific
Chemical-specific
Exposure frequency = EF
day/year
350
(EPA 1989a)
250
(EPA 1991a)
40
(EPA 1992)
20
350
(EPA 1989a)
Exposure duration = ED
years
30
(EPA 1989a)
25
(EPA 1991a)
30
(EPA 1989a)
1
30
(EPA 1989a)
Conversion factor = CF5
g/kg
1000
1000
1000
1000
1000
Volatilization factor = VF
m3/kg
Chemical-specific
Chemical-specific
Chemical-specific
Chemical-specific
Chemical-specific
Fraction of vegetative cover = V
unitless
0.5
(EPA 1996)
0.5
(EPA 1996)
0.5
(EPA 1996)
0.5
(EPA 1996)
0.5
(EPA 1996)
Mean annual windspeed = Um
m/s
4.69
(EPA 1996)
4.69
(EPA 1996)
4.69
(EPA 1996)
4.69
(EPA 1996)
4.69
(EPA 1996)
Equivalent threshold value of windspeed at 7 m = Ut
m/s
11.32
(EPA 1996)
11.32
(EPA 1996)
11.32
(EPA 1996)
11.32
(EPA 1996)
11.32
(EPA 1996)
Function dependent on Um/Ut= F(x)
unitless
0.194
(Cowherd 1985)
0.194
(Cowherd 1985)
0.194
(Cowherd 1985)
0.194
(Cowherd 1985)
0.194
(Cowherd 1985)
Inverse of the mean concentration at the center of a 0.5 acre-square source = Q/C
(g m3)/
(m2 s kg)
90.8
(EPA 1996)
90.8
(EPA 1996)
90.8
(EPA 1996)
90.8
(EPA 1996)
90.8
(EPA 1996)
Seconds in an hour = CF3
s/h
3600
3600
3600
3600
3600
Total inhalation rate = IRair
m3/day
20
(EPA 1989a)
20
(EPA 1989a)
6.7
(8 hours)
(EPA 1992)
20
(EPA 1989a)
20
(EPA 1989a)
Conversion Factor = CF2
days/yr
365
365
365
365
365
Body weight = BW
kg
70 (adult)
(EPA 1991a)
70 (adult)
(EPA 1991a)
70 (adult)
(EPA 1991a)
70 (adult)
(EPA 1991a)
70 (adult)
(EPA 1991a)
Lifetime = LT
years
70
(EPA 1989a)
70
(EPA 1989a)
70
(EPA 1989a)
70
(EPA 1989a)
70
(EPA 1989a)
Averaging time = AT
years
LT (carcinogen)
ED (noncarcinogen)
LT (carcinogen)
ED (noncarcinogen)
LT (carcinogen)
ED (noncarcinogen)
LT (carcinogen)
ED (noncarcinogen)
LT (carcinogen)
ED (noncarcinogen)