Probability (Risk) of Fetal Blood Lead Level Exceeding Lead Blood Target Level Equation Fetal Blood Lead Level Concentration Equation Enter Your Soil Lead Concentration(s) PbS (Soil Lead Concentration) µg/g or ppm Site-Specific Worker Exposure Parameters ATS, D (Averaging time (same for soil and dust)) days/yr EFS, D (Exposure frequency (same for soil and dust)) days/yr IRS (Soil ingestion rate (including soil-derived indoor dust)) g/day PbBt (Target PbB level of concern (e.g., 2-8 µg/dL)) µg/dL Current EPA Recommended Lead-Specific Parameters (NHANES 2009-2014) AFS, D (Absorption fraction (same for soil and dust)) unitless BKSF (Biokinetic Slope Factor) µg/dL per µg/day GSDi (Geometric Standard Deviation PbB) unitless PbB0 (Baseline PbB) µg/dL Rfetal/maternal (Fetal/Maternal PbB ratio) unitless Variables Calculated Based on Above Inputs PbBadult (PbB of adult worker, geometric mean) µg/dL PbBfetal, 0.95 (95th percentile PbB among fetuses of adult workers) µg/dL Notes
The value of 5 µg/dL for the Target PbB in fetus (PbBt ) is simply the midpoint of the recommended range of 2 to 8 µg/dL. To replicate the GSDi and PbBo from Analysis of NHANES 2007-2010 use 1.7 and 0.7, respectively.
To replicate the GSDi and PbBo from Analysis of NHANES 1999-2004 use 1.8 and 1.0, respectively.
To replicate the GSDi and PbBo from Analysis of NHANES III (Phases 1&2) use 2.1. and 1.5, respectively.
This calculator is a methodology for assessing risks associated with non-residential exposures to lead in soil. The methodology focuses on estimating fetal blood lead concentrations in women exposed to lead-contaminated soils. This approach also provides tools for evaluating risks of elevated blood lead concentrations among exposed adults. Based on the TRW's analysis of the data collected in the completed NHANES III survey (1999-2004), updated ranges for the baseline adult blood lead concentration (PbB) and GSDi adult parameters in the ALM have been included in the spreadsheets. However, recent scientific evidence has demonstrated adverse health effects at blood lead concentrations below 10 µg/dL down to 5 µg/dL, and possibly below. OSRTI is developing a new soil lead policy to address this new information. Until that soil lead policy is finalized, regional risk assessors and managers should consult with the TRW's Lead Committee before applying these updated values for risk assessment. https://www.epa.gov/superfund/lead-superfund-sites-software-and-users-manuals#recommend)
