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```									Calculations of Preliminary Remediation Goals (PRGs)

Calculations of Preliminary Remediation Goals (PRGs)

Exposure Variable PbBfetal, 0.95 Rfetal/maternal BKSF GSDi PbB0 IRS IRS+D WS KSD AFS, D EFS, D ATS, D
PRG
1

PRG 1 Equation 1* 2**
X X X X X X X X X X X X X X X X X X X X

Description of Exposure Variable
95th percentile PbB in fetus Fetal/maternal PbB ratio Biokinetic Slope Factor Geometric standard deviation PbB Baseline PbB Soil ingestion rate (including soil-derived indoor dust) Total ingestion rate of outdoor soil and indoor dust Weighting factor; fraction of IRS+D ingested as outdoor soil Mass fraction of soil in dust Absorption fraction (same for soil and dust) Exposure frequency (same for soil and dust) Averaging time (same for soil and dust) Preliminary Remediation Goal

Units
ug/dL -ug/dL per ug/day -ug/dL g/day g/day ---days/yr days/yr ppm

Values for Non-Residential Exposure Scenario Using Equation 1 Using Equation 2 GSDi = Hom GSDi = Het GSDi = Hom GSDi = Het 10 0.9 0.4 2.1 1.5 0.050 ---0.12 219 365 1,235 10 0.9 0.4 2.3 1.7 0.050 ---0.12 219 365 780 10 0.9 0.4 2.1 1.5 -0.050 1.0 0.7 0.12 219 365 1,235 10 0.9 0.4 2.3 1.7 -0.050 1.0 0.7 0.12 219 365 780

Equation 1 does not apportion exposure between soil and dust ingestion (excludes WS, KSD). When IRS = IRS+D and WS = 1.0, the equations yield the same PRG.

*Equation 1, based on Eq. 4 in USEPA (1996).

PRG =

([PbB95fetal/(R*(GSDi1.645)])-PbB0)*ATS,D BKSF*(IRS+D*AFS,D*EFS,D)

**Equation 2, alternate approach based on Eq. 4 and Eq. A-19 in USEPA (1996).

PRG =

([PbBfetal,0.95/(R*(GSDi1.645)])-PbB0)*ATS,D BKSF*([(IRS+D)*AFS*EFS*WS]+[KSD*(IRS+D)*(1-WS)*AFD*EFD])

Source: U.S. EPA (1996). Recommendations of the Technical Review Workgroup for Lead for an Interim Approach to Assessing Risks Associated with Adult Exposures to Lead in Soil

Calculations of Preliminary Remediation Goals (PRGs)

Calculations of Blood Lead Concentrations (PbBs)

Exposure Variable PbS Rfetal/maternal BKSF GSDi PbB0 IRS IRS+D WS KSD AFS, D EFS, D ATS, D PbBadult PbBfetal, 0.95 PbBt
1

PbB Equation1 1* 2**
X X X X X X X X X X X X X X X X X X X X

Description of Exposure Variable
Soil lead concentration Fetal/maternal PbB ratio Biokinetic Slope Factor Geometric standard deviation PbB Baseline PbB Soil ingestion rate (including soil-derived indoor dust) Total ingestion rate of outdoor soil and indoor dust Weighting factor; fraction of IRS+D ingested as outdoor soil Mass fraction of soil in dust Absorption fraction (same for soil and dust) Exposure frequency (same for soil and dust) Averaging time (same for soil and dust) PbB of adult worker, geometric mean 95th percentile PbB among fetuses of adult workers Target PbB level of concern (e.g., 10 ug/dL)

Units
ug/g or ppm -ug/dL per ug/day -ug/dL g/day g/day ---days/yr days/yr ug/dL ug/dL ug/dL %

Values for Non-Residential Exposure Scenario Using Equation 1 Using Equation 2 GSDi = Hom GSDi = Het GSDi = Hom GSDi = Het 750 0.9 0.4 2.1 1.5 0.050 ---0.12 219 365 2.6 7.9 10.0 2.5% 750 0.9 0.4 2.3 1.7 0.050 ---0.12 219 365 2.8 9.8 10.0 4.8% 750 0.9 0.4 2.1 1.5 -0.050 1.0 0.7 0.12 219 365 2.6 7.9 10.0 2.5% 750 0.9 0.4 2.3 1.7 -0.050 1.0 0.7 0.12 219 365 2.8 9.8 10.0 4.8%

P(PbBfetal > PbBt) Probability that fetal PbB > PbBt, assuming lognormal distribution
Equation 1 does not apportion exposure between soil and dust ingestion (excludes W S, KSD). When IRS = IRS+D and WS = 1.0, the equations yield the same PbBfetal,0.95.

*Equation 1, based on Eq. 1, 2 in USEPA (1996).

PbB adult = PbB fetal, 0.95 =

(PbS*BKSF*IRS+D*AFS,D*EFS/ATS.D) + PbB0 PbBadult * (GSDi1.645 * R)

**Equation 2, alternate approach based on Eq. 1, 2, and A-19 in USEPA (1996). PbS*BKSF*([(IRS+D)*AFS*EFS*WS]+[KSD*(IRS+D)*(1-WS)*AFD*EFD])/365+PbB0 PbB =

PbB fetal, 0.95 =

Source: U.S. EPA (1996). Recommendations of the Technical Review Workgroup for Lead for an Interim Approach to Assessing Risks Associated with Adult Exposures to Lead in Soil

Printed 6/27/2009 10:33 AM

Copy Range Defaults (DO NOT CHANGE THESE!!)

Values for Non-Residential Exposure Scenario Using Equation 1
GSDi = Hom GSDi = Het

PbB Calculation

Values for Non-Residential Exposure Sc Using Equation 1
GSDi = Hom GSDi = Het

Using Equation 2
GSDi = Hom GSDi = Het

Using Equati

10 0.9 0.4 2.1 1.5 0.050 ---0.12 219 365 1,235

10 0.9 0.4 2.3 1.7 0.050 ---0.12 219 365 780

10 0.9 0.4 2.1 1.5 -0.050 1.0 0.7 0.12 219 365 1,235

10 0.9 0.4 2.3 1.7 -0.050 1.0 0.7 0.12 219 365 780

750 0.9 0.4 2.1 1.5 0.050 ---0.12 219 365 2.6 7.9 10.0 2.5%

750 0.9 0.4 2.3 1.7 0.050 ---0.12 219 365 2.8 9.8 10.0 4.8%

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Non-Residential Exposure Scenario Using Equation 2
GSDi = Hom GSDi = Het

750 0.9 0.4 2.1 1.5 -0.050 1.0 0.7 0.12 219 365 2.6 7.9 10.0 2.5%

750 0.9 0.4 2.3 1.7 -0.050 1.0 0.7 0.12 219 365 2.8 9.8 10.0 4.8%

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