![[logo] US EPA](http://rais.ornl.gov/epa-source/wget/www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
Preliminary Remediation Goals for Radionuclides |
|
|---|
What's New
The What's New section keeps users informed of toxicity value changes, exposure parameter changes, chemical-specific parameter changes, and any equation format changes. Please check this site frequently to be advised of any recent changes.
March 2009
Half-lifes were added for Ba-133m+D, Cf-248+D, Fm-254+D, Hf-182+D, Ir-192m+D, Np-237+D, Pd-103+D, Ra-227+D, Ra-228+D, Sm-145+D, U-232+D and U-235+D. Because of these additions, PRG are now being generated in the calculator. Downoad tables will be updated at the next revision.
December 2008
The half-life of Am-242m was changed from 152 to 141 years.
July 2004
The default values for ETowo (Outdoor Worker Exposure Time Outdoor) and ETiwi (Indoor Worker Time Indoor) have been changed back to 0.33 from 1.0. This change is because the external exposure route was inadvertently affected. To sustain the desired intention of a worker being exposed 8 hours of the 8 hour worker day, the inhalation rate for workers was changed to 60 m3/day (this reflects an hourly inhalation rate of 2.5m3/hour).
The default values for ETowo (Outdoor Worker Exposure Time Outdoor) and ETiwi (Indoor Worker Time Indoor) have been changed from 0.33 to 1.0. This change reflects the desired intention of a worker being exposed 8 hours of the 8 hour worker day.
September 2002
The format of the PRG website has been updated to reflect the new EPA standard template.
August 2002
The agricultural equations have been updated to include ingestion of swine, ingestion of eggs, and ingestion of poultry.
May 2002
Adult-only ingestion slope factors for workers have been updated for the following radionuclides:
- Ra-226+D => 2.95E-10 (risk/pCi)
- U-235+D => 5.03-11 (risk/pCi)
- U-238+D => 5.62E-11 (risk/pCi)
Also, the soil equations for tritium (H-3) have been modified to reflect a soil-to-air volatilization factor of 17 (m3/kg) which replaces the Particulate Emission Factor.
August 2001
Please note that this PRG database is maintaining new, nonstandard PRGs when compared to EPA RAGs PartB. The worker soil exposure PRGs have been separated to indoor and outdoor scenarios. Also fish ingestion has been added.
January 2001
Note to Users: There has been a new release of toxicity values for radionuclides as presented in HEAST. Essentially, every slope factor has changed. In addition, oral values are tabulated separately for ingestion of tap water, dietary intakes (food), and incidental soil ingestion. Please consult the User's Guide section on radionuclide carcinogenicity for the derivation of radionuclide slope factors and guidance on their use. Also please note that the output of the Preliminary Remediation Goal and Human Health Exposure Modeling sections will reflect these changes in toxicity values.
This site is maintained and operated through an Interagency Agreement between the EPA Office of Superfund and Oak Ridge National Laboratory. For questions or comments please contact Stuart Walker at the Office of Superfund Remediation and Technology Innovation.