Parameter Estimation Guidelines for Risk-Based Corrective Action ...
Parameter Estimation Guidelines for Risk-Based Corrective Action ...
Parameter Estimation Guidelines for Risk-Based Corrective Action ...
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Groundwater Services, Inc.<br />
Equation CM-1: Surface Soil Volatilization Factor (VFss)<br />
Uair<br />
breathing zone<br />
d affected surficial soils<br />
W<br />
δ air<br />
diffusing<br />
vapors<br />
CM-1a:<br />
VF<br />
ss<br />
( )<br />
3<br />
⎡<br />
eff<br />
mg / m − air ⎤ 2W<br />
s<br />
Ds<br />
H<br />
⎢<br />
⎥<br />
⎣⎢<br />
( mg / kg − soil)<br />
⎦⎥ = ρ<br />
Uairδair<br />
πτ θ + k ρ + Hθ<br />
or CM-1b:<br />
VF<br />
whichever is less<br />
Equation CM-2: Soil Particulate Emission Factor (PEF)<br />
ss<br />
( )<br />
3<br />
⎡ mg / m − air<br />
⎢<br />
⎣⎢<br />
mg / kg − soil<br />
( )<br />
( ) ×<br />
ws s s as<br />
⎤ Wρsd<br />
⎥ = × 10<br />
⎦⎥<br />
Uairδairτ<br />
3<br />
10<br />
3<br />
Uair<br />
d<br />
P e<br />
breathing zone<br />
affected surficial soils<br />
δ air<br />
diffusing<br />
vapors<br />
( )<br />
3<br />
⎡ mg / m − air<br />
PEF⎢<br />
⎣⎢<br />
mg / kg − soil<br />
( )<br />
⎤ PW<br />
e<br />
⎥ = × 10<br />
⎦⎥<br />
Uairδ<br />
air<br />
3<br />
W<br />
Equation CM-3: Subsurface Soil Volatilization Factor (VFsamb)<br />
L s<br />
U air<br />
breathing zone δair<br />
vadose zone<br />
d i f f u s i n g v a p o r s<br />
affected subsurface soils<br />
W<br />
CM-3a:<br />
⎡ 3<br />
( mg / m − air)<br />
⎤<br />
H<br />
VF ⎢<br />
⎥<br />
s<br />
samb<br />
⎢( mg / kg − soil)<br />
⎥ = ρ<br />
⎡<br />
⎣<br />
⎦ θws + ksρs + Hθas<br />
⎢1<br />
⎣⎢<br />
or CM-3b:<br />
whichever is less<br />
[ ] +<br />
( )<br />
⎡ 3<br />
mg / m − air<br />
VF ⎢<br />
samb<br />
⎢ mg / kg − soil<br />
⎣<br />
( )<br />
3<br />
x10<br />
Uairδair L ⎤<br />
s<br />
Ds eff ⎥<br />
W ⎦⎥<br />
⎤<br />
⎥ W sds<br />
3<br />
10<br />
⎥ = ρ<br />
Uairδairτ x<br />
⎦<br />
Equation CM-4: Subsurface Soil to Enclosed Space Volatilization Factor (VFsesp)<br />
ER: air<br />
exchange<br />
rate<br />
L s<br />
enclosed-space<br />
foundation cracks<br />
,,,,,,,,,,,,,,<br />
d i f f u s i n g<br />
affected subsurface soils<br />
W<br />
v a p o r s<br />
L<br />
b<br />
: Vol. / Infil. Area Ratio<br />
L crack : Foundation<br />
Thickness<br />
vadose zone<br />
CM-4a:<br />
Hρ<br />
⎡<br />
s Ds eff / L ⎤<br />
s<br />
⎡ 3<br />
( mg / m − air)<br />
⎤<br />
⎢ ⎥<br />
ws ks s H as ER LB<br />
VF ⎢<br />
⎥<br />
[ 3<br />
sesp<br />
10<br />
⎢( mg / kg − soil)<br />
⎥ = θ + ρ + θ ] ⎣⎢<br />
⎦⎥<br />
x<br />
⎣<br />
⎦ Ds eff / Ls<br />
Ds eff / L<br />
1 + ⎡ s<br />
ER L eff<br />
⎣ ⎢ ⎤<br />
⎡<br />
⎤<br />
⎥<br />
⎢ B ⎦⎥ + ⎢<br />
⎥<br />
( Dcrack<br />
/ L<br />
⎣⎢<br />
crack ) η<br />
⎦⎥<br />
or CM-4b:<br />
whichever is less<br />
( )<br />
⎡ 3<br />
mg / m − air<br />
VF ⎢<br />
sesp<br />
⎢ mg / kg − soil<br />
⎣<br />
( )<br />
⎤<br />
⎥ sds<br />
3<br />
10<br />
⎥ = ρ LBERτ x<br />
⎦<br />
FIGURE 2. CROSS-MEDIA PARTITIONING EQUATIONS IN THE RBCA SPREADSHEET SYSTEM<br />
Continued<br />
NGWA Petroleum Hydrocarbons Conference 4 <strong>Parameter</strong> <strong>Estimation</strong> <strong>Guidelines</strong><br />
Houston, Texas, November 1996<br />
<strong>for</strong> RBCA Modeling