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page title goes here Risk Assessment

Default PRG Download Area

Default PRG tables, based on a target cancer risk of 1 × 10-6, are available for download in Excel and PDF formats. The summary table includes the total PRGs for select land use (resident, composite worker, farmer, and soil-to-groundwater) and media (soil, water, and air) combinations. The composite tables include the individual route PRGs and the total PRGs for select default land use and media combinations. Indoor and outdoor worker default tables are not provided, because site-specific screening is recommended for the composite worker PRGs. The composite tables also include tables of toxicity values, soil-to-plant transfer factors, and animal transfer factors.

The following table lists all available, downloadable land use and media combinations for the summary table or composite table and the default PRG type. The Peak PRG option was selected for soil and 2-D external exposure, as soil is not considered to be continually contaminated. For all other media, it was assumed that the contamination is continuous, and the secular equilibrium PRG option would be the most protective. Reasons for continuous contamination include:

  • contamination by stack emissions or emanation from soil, as is the case for radon
  • water contamination from surrounding soil
  • biota contamination due to constant contact with water and soil sources, where time from seed to harvest allows progeny to ingrow

September 2022 Tables

Included in Summary Table
Land Use Media Default PRG Type
Resident Soil Peak PRG
Composite Worker Soil Peak PRG
Farmer Soil Peak PRG
Resident Air Secular Equilibrium
Composite Worker Air Secular Equilibrium
Farmer Air Secular Equilibrium
Resident Finfish Secular Equilibrium
Resident Tap Water Secular Equilibrium
Farmer Tap Water Secular Equilibrium
Resident Soil to Groundwater Risk-based Secular Equilibrium
Resident Soil to Groundwater MCL-based Secular Equilibrium
Not Included in Summary Table, but Available in Composite Table
Land Use Media Default PRG Type
Resident 2-D Peak PRG
Composite Worker 2-D Peak PRG
Resident Tap Water Produce Supporting Table Secular Equilibrium
Farmer Biota Secular Equilibrium
Farmer Tap Water Produce Supporting Table Secular Equilibrium

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pCi Bq
(TR=1E-06) (TR=1E-06) (TR=1E-06) (TR=1E-06)
Summary Table (PDF) (XLS) (PDF) (XLS)
Composite Table (PDF) (XLS) (PDF) (XLS)