Ill. Admin. Code tit. 35, pt. 742, subpt. L, app C, tbl. D

Current through Register Vol. 48, No. 49, December 6, 2024

Table D - RBCA Parameters

Symbol	Parameter	Units	Source	Parameter Value(s)
ATc	Averaging Time for Carcinogens	yr	RBCA	70
ATn	Averaging Time for Noncarcinogens	yr	RBCA	Residential = 30 Industrial/Commercial = 25 Construction Worker = 0.115
BW	Adult Body Weight	kg	RBCA	70
Csource	The greatest potential concentration of the contaminant of concern in the groundwater at the source of the contamination, based on the concentrations of contaminants in groundwater due to the release and the projected concentration of the contaminant migrating from the soil to the groundwater.	mg/L	Field Measurement	Site-Specific
C(x)	Concentration of Contaminant in Groundwater at Distance X form the source	mg/L	Equation R26 in Appendix C, Table C	Calculated Value
C(x)/Csource	Steady-State Attenuation Along the Centerline of a Dissolved Plume	unitless	Equation R15 in Appendix C, Table C	Calculated Value
d	Lower Depth of Surficial Soil Zone	cm	Field Measurement	100 or Site-Specific (not to exceed 100)
Dair	Diffusion Coefficient in Air	cm2/s	Appendix C, Table E	Chemical-Specific
Dwater	Diffusion Coefficient in Water	cm2/s	Appendix C, Table E	Chemical-Specific

Symbol	Parameter	Units	Source	Parameter Value(s)
Dseff	Effective Diffusion Coefficient in Soil Based on Vapor-Phase Concentration	cm2/s	Equation R6 in Appendix C, Table C	Calculated Value
ED	Exposure Duration	yr	RBCA	Residential = 30 Industrial/Commercial = 25 Construction Worker = 1
EF	Exposure Frequency	d/yr	RBCA	Residential = 350 Industrial/Commercial = 250 Construction Worker = 30
erf	Error Function	unitless	Appendix C, Table G	Mathematical Function
foc	Organic Carbon Content of Soil	g/g	RBCA or Field Measurement (See Appendix C, Table F)	Surface Soil = 0.006 Subsurface Soil = 0.002 or Site-Specific
GWcomp	Groundwater Objective at the Compliance Point	mg/L	Appendix B, Table E, 35 IAC 620.Subpart F, or Equation R25 in Appendix C, Table C	Site-Specific
GWsource	Groundwater Concentration at the Source	mg/L	Equation R13 in Appendix C, Table C	Calculated Value
H'	Henry's Law Constant	cm3water/cm3air	Appendix C, Table E	Chemical-Specific
i	Hydraulic Gradient	cm/cm (unitless)	Field Measurement (See Appendix C, Table F)	Site-Specific
I	Infiltration Rate	cm/yr	RBCA	30
IRair	Daily Outdoor Inhalation Rate	m3/d	RBCA	20
IRsoil	Soil Ingestion Rate	mg/d	RBCA	Residential = 100 Industrial/Commercial = 50 Construction Worker = 480
IRw	Daily Water Ingestion Rate	L/d	RBCA	Residential = 2 Industrial/Commercial = 1
K	Aquifer Hydraulic Conductivity	cm/d for Equations R15, R19 and R26 cm/yr for Equation R24	Field Measurement (See Appendix C, Table F)	Site-Specific
Koc	Organic Carbon Partition Coefficient	cm3/g or L/kg	Appendix C, Table E or Appendix C, Table I	Chemical-Specific

Symbol	Parameter	Units	Source	Parameter Value(s)
ks (non-ionizing organics)	Soil Water Sorption Coefficient	cm3water/gsoil	Equation R20 in Appendix C, Table C	Calculated Value
ks (ionizing organics)	Soil Water Sorption Coefficient	cm3water/gsoil	Equation R20 in Appendix C, Table C	Chemical and pH-Specific (See Appendix C, Table I)
ks (inorganics)	Soil Water Sorption Coefficient	cm3water/gsoil	Appendix C, Table J	Chemical and pH-Specific
Ls	Depth to Subsurface Soil Sources	cm	RBCA	100
LFsw	Leaching Factor	(mg/Lwater)/ (mg/kgsoil)	Equation R14 in Appendix C, Table C	Calculated Value
M	Soil to Skin Adherence Factor	mg/cm2	RBCA	0.5
Pe	Particulate Emission Rate	g/cm2-s	RBCA	6.9 * 10-14
RAFd	Dermal Relative Absorption Factor	unitless	RBCA	0.5
RAFd (PNAs)	Dermal Relative Absorption Factor	unitless	RBCA	0.05
RAFd (inorganics)	Dermal Relative Absorption Factor	unitless	RBCA	0
RAFo	Oral Relative Absorption Factor	unitless	RBCA	1.0
RBSLair	Carcinogenic Risk-Based Screening Level for Air	µg/m3	Equation R9 in Appendix C, Table C	Chemical-, Media-, and Exposure Route-Specific
RBSLair	Noncarcinogenic Risk-Based Screening Level for Air	µg/m3	Equations R10 in Appendix C, Table C	Chemical-, Media-, and Exposure Route-Specific
RfDi	Inhalation Reference Dose	mg/kg-d	IEPA (IRIS/HEASTa)	Toxicological-Specific
RfDo	Oral Reference Dose	mg/(kg-d)	IEPA (IRIS/HEASTa)	Toxicological-Specific (Note: for Construction Worker use subchronic reference doses)
SA	Skin Surface Area	cm2/d	RBCA	3,160

Symbol	Parameter	Units	Source	Parameter Value(s)
Sd	Source Width Perpendicular to Groundwater Flow Direction in Vertical Plane	cm	Field Measurement	For Migration to Groundwater Route: Use 200 or Site-Specific For Groundwater remediation objective: Use Site-Specific
Sw	Source Width Perpendicular to Groundwater Flow Direction in Horizontal Plane	cm	Field Measurement	Site-Specific
SFi	Inhalation Cancer Slope Factor	(mg/kg-d)-1	IEPA (IRIS/HEASTa)	Toxicological-Specific
SFo	Oral Slope Factor	(mg/kg-d)-1	IEPA (IRIS/HEASTa)	Toxicological-Specific
THQ	Target Hazard Quotient	unitless	RBCA	1
TR	Target Cancer Risk	unitless	RBCA	Residential = 10-6 at the point of human exposure Industrial/Commercial = 10-6 at the point of human exposure Construction Worker = 10-6 at the point of human exposure
U	Specific Discharge	cm/d	Equation R19 in Appendix C, Table C	Calculated Value
Uair	Average Wind Speed Above Ground Surface in Ambient Mixing zone	cm/s	RBCA	225
[MU]gw	Groundwater Darcy Velocity	cm/yr	Equation R24 in Appendix C, Table C	Calculated Value
VFp	Volatilization Factor for Surficial Soils Regarding Particulates	kg/m3	Equation R5 in Appendix C, Table C	Calculated Value
VFsamb	Volatilization Factor (Subsurface Soils to Ambient Air)	(mg/m3air)/(mg/kgsoil) or kg/m3	Equation R11 in Appendix C, Table C	Calculated Value

Symbol	Parameter	Units	Source	Parameter Value(s)
VFss	Volatilization Factor for Surficial Soils	kg/m3	Use Equations R3 and R4 in Appendix C, Table C	Calculated Value from Equation R3 or R4 (whichever is less)
W	Width of Source Area Parallel to Direction to Wind or Groundwater Movement	cm	Field Measurement	Site-Specific
w	Average Soil Moisture Content	gwater/gsoil	RBCA or Field Measurement (See Appendix C, Table F)	0.1, or Surface Soil (top 1 meter) = 0.1 Subsurface Soil (below 1 meter) = 0.2, or Site-Specific
X	Distance along the Centerline of the Groundwater Plume Emanating from a Source. The x direction is the direction of groundwater flow	cm	Field Measurement	Site-Specific
[ALPHA]x	Longitudinal Dispersivity	cm	Equation R16 in Appendix C, Table C	Calculated Value
[ALPHA]y	Transverse Dispersivity	cm	Equation R17 in Appendix C, Table C	Calculated Value
[ALPHA]z	Vertical Dispersivity	cm	Equation R18 in Appendix C, Table C	Calculated Value
[DELTA]air	Ambient Air Mixing Zone Heights	cm	RBCA	200
[DELTA]gw	Groundwater Mixing Zone Thickness	cm	RBCA	200
[THETA]as	Volumetric Air Content in Vadose Zone Soils	cm3air/cm3soil	RBCA or Equation R21 in Appendix C, Table C	Surface Soil (top 1 meter) = 0.28 Subsurface Soil (below 1 meter) = 0.13, o r Gravel = 0.05 Sand = 0.14 Silt = 0.16 Clay = 0.17, or Calculate Value

Symbol	Parameter	Units	Source	Parameter Value(s)
[THETA]ws	Volumetric Water Content in Vadose Zone Soils	cm3water/cm3soil	RBCA or Equation R22 in Appendix C, Table C	Surface Soil (top 1 meter) = 0.15 Subsurface Soil (below 1 meter) = 0.30, or Gravel = 0.20 Sand = 0.18 Silt = 0.16 Clay = 0.17, or Calculated Value
[THETA]T	Total Soil Porosity	cm3/cm3soil	RBCA or Equation R23 in Appendix C, Table C	0.43, or Gravel = 0.25 Sand = 0.32 Silt = 0.40 Clay = 0.36, or Calculated Value
[LAMBDA]	First Order Degradation Constant	d-1	Appendix C, Table E	Chemical-Specific
[PI]	pi			3.1416
[RHO]s	Soil Bulk Density	g/cm3	RBCA or Field Measurement (See Appendix C, Table F)	1.5, or Gravel = 2.0 Sand = 1.8 Silt = 1.6 Clay = 1.7, or Site-Specific
[RHO]w	Water Density	g/cm3	RBCA	1
[TAU]	Averaging Time for Vapor Flux	s	RBCA	9.46 * 108

Ill. Admin. Code tit. 35, pt. 742, subpt. L, app C, tbl. D

Amended at 31 Ill. Reg. 4063, effective February 23, 2007