Preliminary Remediation Goals (PRG) Calculator

Stuart Walker - walker.stuart@epa.gov, (703) 603-8748

Office of Superfund Remediation and Technology Innovation, US Environmental Protection Agency

PRG: http://epa-prgs.ornl gov/radionuclides

What is PRG?

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PRG Calculator



How does the PRG Calculator Work?

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PRG stands for Preliminary
Remediation Goal.

PRGs are the initial cleanup goals at
a Superfund site and usually are
not final cleanup levels.

Used when there is no appropriate
government regulation of cleanup
levels.

Soil to Groundwater Exposure

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Drinking Water





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•	The PRG Calculator is a tool that allows EPA to calculate initial cleanup
levels for radiation in soil, water, and air at Superfund sites.

•	Uses slope factors to calculate cleanup levels based on a target cancer
risk of 10"6.

•	Slope factors provide cancer risk posed by lifetime exposure to
specific radionuclides. Slope factors also take into account the type
of exposure (inhalation, ingestion, or external) and amount of
exposure. For example, a resident on a site would expect to have a
different exposure level than a worker on the same site.

•	Target cancer risk of 10"6 means that a person exposed to the
contamination has a one in a million chance of developing cancer.
(Target is based on highest estimated level of exposure. Most
people will have less of a chance of developing cancer.)

•	The exposure pathways calculated by the PRG calculator are shown in
the diagrams below.

Outdoor (or Composite) Worker: Soil Exposure

Resident: Soil Exposure

Indoor Worker: Soil Exposure

Breathing in Dust

Particles External
Exposure

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Eating Fruits and
Vegetables

Incidental Soil
estion

Agricultural: Soil Exposure

Breathing in Dust
Particles

Eating Fish,
Chicken, and
Eggs

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Tapwater Ingestion Exposure

Breathing in Vapors

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Eating Fruits and
Consuming Vegetables
Pork, Beef,
and Milk	Incidental Soil

Ingestion

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Drinking Water

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Fish Ingestion Exposure

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Agricultural Land Use

PRG Calculation

Residential Land Use

Industrial Land Use

Slope Factors

PRG Equations

Breathing in Dust
Particles

External
Exposure

Incidental Soil
Ingestion

External
Exposure

Incidental Soil
Inqestion

ng in Dust
Particles

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