The Virginia Voluntary Remediation Program (VRP) Risk Assessment Guidance offers information that will help interested parties conduct risk assessments required as a component of their participation in the VRP.

The regulatory basis for performing risk assessments under the Virginia VRP is found in the Voluntary Remediation Regulations section 9 VAC 20-160-70(A)(1)(a). The risk assessment is included in the site characterization report and should include an evaluation of the risks to human health and the environment posed by the release. If the risk assessment shows that a remedial action is necessary, a proposed set of remediation levels as described in 9 VAC 20-160-90 should also be included.

Risk assessments under the VRP generally follow the methodology described in Risk Assessment Guidance for Superfund (RAGS). The risk assessment process consists of four major steps. These steps are data collection and evaluation, exposure assessment, toxicity assessment, and risk characterization. These steps, as applied to the VRP, are described in the guidance.

How to Use this Guidance

This guidance is designed to be used as a web-based document. Follow the links above to read the guidance online and download tables on an individual basis.

Also see Instructions for Using VRP Calculation Spreadsheets for help in using the tables.

Periodic Updates

Please note that the guidance includes screening levels and toxicity values that are updated periodically by EPA. VRP staff will make every attempt to update the information in the guidance accordingly. The guidance is updated periodically to incorporate new toxicity information and new guidance from EPA. We are currently compiling a mailing list to notify our users by email when the guidance is updated. The email notifications will be provided as a convenience to our participants. However, please note that it is the participant's responsibility to ensure that the most current toxicity information is used in VRP risk assessments regardless of whether the VRP guidance has been updated and regardless of whether they have received notification. If you would like to be included on the mailing list please send an email to patricia.mcmurray@deq.virginia.gov.

May 2013

The VRP Risk Assessment Guidance screening and calculation tables have been updated.  These updates include:

• Toxicity factor and screening level updates from the EPA Regional Screening Level (RSL) Table from November, 2012.
• Chemical properties have been updated to be consistent with the RSL Table.  Please be advised some of these changes have resulted in different screening values for the vapor and soil to groundwater pathways for some compounds.
• Non-carcinogenic screening levels that are lower at a Target Hazard Quotient  (THQ) of 0.1 than the carcinogenic screening level at 10^-6 replace the carcinogenic values.
• TCE residential calculations in the gwcalcs spreadsheet were corrected.
• Formulas in the soilcalcs construction worker sheet were corrected to use subchronic RfDs and RfCs.

A statement regarding analysis of 1,4-dioxane has been added to Section 2.2 of the guidance: 

"1,4-dioxane is included on the EPA Target Compound List (TCL) and is therefore included on the VRP screening and calculation tables.  It has come to our attention that 1,4-dioxane is not always automatically included for analysis when SW-846 Method 8260 is requested.  1,4-dioxane has been used as a solvent stabilizer for 1,1,1-trichloroethane (TCA) and and possibly other solvents including trichloroethylene (TCE).  The participant should insure that 1,4-dioxane is analyzed when 1,1,1-TCA and/or TCE are known or suspected to have been used at a site."

August 2012

The VRP Risk Assessment Guidance screening and calculation tables have been updated.  These updates include:

• Toxicity factor and screening level updates from the EPA Regional Screening Level (RSL) Table from April, 2012.
• Some of the sediment screening levels on Table 2.8 have been changed to reflect 10x the adjusted RSL rather than 10x the Tier II value.  The equations had been mistakenly linked to the Tier II value which resulted in some of the screening levels being based on migration to groundwater rather than direct toxicity.
• An error in some of the mutagenic equations on swcalcs was corrected.