Welcome

Welcome to the EPA's "Dose Compliance Concentrations for Radionuclides at Superfund Sites" (DCC) Download and Calculator website for demonstrating compliance with dose-based Applicable or Relevant and Appropriate Requirements (ARARs). The recommended DCCs on this website are dose levels for contaminated soil, water, and air. If this is your first time using the DCC Calculator, it is strongly recommended that you first read "Radiation Risk Assessment At CERCLA Sites: Q & A".

This tool presents recommended DCCs calculated using suggested default input parameters and the latest dose conversion factors adopted for Superfund use. In addition, you may modify the input parameters to create site-specific DCCs to meet the needs of your site. To ensure proper application of the DCCs, please see further guidance on how to use the DCCs presented on this site located in the User's Guide, What's New, FAQ, and Download Area links.

The EPA has prepared a fact sheet for the general public that describes DCC uses, DCC calculator operation, and land uses available for assessment. Additionally, this fact sheet describes the Preliminary Remediation Goal ( PRG ) and DCC calculators in greater detail for EPA staff. The Office of Solid Waste and Emergency Response ( OSWER ) Directive and the Superfund Radiation Risk Assessment: A Community Toolkit were developed by the EPA to help the public understand more about the risk assessment process used at Superfund sites with radioactive contamination.

The DCC calculator was largely developed based on the PRG calculator and benefited from its peer reviews . The DCC calculator was previously peer reviewed and the documentation of those peer reviews may be seen here. The DCC calculator results were previously verified. The documentation from these may be seen on the Internal Verification and External Verification pages , which also benefited from the external verification review of the PRG calculator. Several other comparison reviews that focused on describing the default parameters in various models may be found here.

Introduction

The purpose of this guidance is to provide a DCC calculation tool to assist risk assessors, remedial project managers, and others involved with dose assessment and decision-making at Comprehensive Environmental Response, Compensation, and Liability Act ( CERCLA ) sites (commonly known as Superfund) in developing DCCs.

This website has been updated after new EPA guidance has been issued. The website was initially made available for use in a transmittal memo entitled "Distribution of OSWER Radionuclide ARAR Dose Compliance Concentrations (DCCs) for Superfund Electronic Calculator", January 28, 2004.

ARAR Dose Compliance Concentrations

Dose conversion factors (DCFs), or "dose coefficients", for a given radionuclide represent the dose equivalent per unit intake (i.e., ingestion or inhalation) or external exposure from emissions of that radionuclide. These DCFs are used to convert a radionuclide concentration in soil, air, water, or foodstuffs to a radiation dose. DCFs may be specified for specific body organs or tissues of interest or as a weighted sum of individual organ dose, termed the effective dose equivalent. These DCFs may be multiplied by the total activity of each radionuclide inhaled or ingested per year, or the external exposure concentration to which a receptor may be exposed, to estimate the dose equivalent to the receptor.

The recommended approach for developing remediation goals is to identify DCCs at scoping, modify them as needed based on site-specific information, and ultimately select remediation levels in the Record of Decision (ROD). In order to set radionuclide-specific DCCs in a site-specific context, however, assessors must answer fundamental questions about the site. Information on the radionuclides that are present onsite, the specific contaminated media, land-use assumptions, and the exposure assumptions behind pathways of individual exposure is necessary in order to develop radionuclide-specific DCCs. The DCC calculator provides the ability to modify the standard default DCC exposure parameters to calculate site-specific DCCs.

Where this recommended database tool is used to develop standard DCCs or calculate site-specific DCCs, it is important to clearly document the equations and exposure parameters used in the calculations. Discussion of the assumptions that go into the DCCs calculated should be included in the document where the DCCs are presented such as a Remedial Investigation (RI) Report or Feasibility Study (FS).

This recommended database tool presents suggested standardized dose-based DCCs and dose-based DCC calculation equations for radioactively contaminated soil, water, air, and foods. Recommended DCCs are presented for residential soil, composite worker soil, outdoor worker soil, indoor worker soil, construction worker soil, recreator soil, air, farmer soil, farmer water, recreator water, farm products, tap water, and fish ingestion. The dose limit used for dose-based DCCs for radionuclides is based on the dose limit in the requirement that is determined to be an ARAR. The suggested standardized DCCs are based on default exposure parameters and incorporate exposure factors that represent the reasonably maximum exposed (RME) individual . This recommended database tool presents DCCs in both activity per area and mass per area units.

At this website, you will find DCCs calculated using the dose conversion factors from International Commission on Radiological Protection (ICRP) 30, ICRP 60, and ICRP 107. This website does not address the calculation of DCCs for ARARs based on ICRP 2 dose conversion factors (e.g., 40 CFR 141.66(d), 10 CFR 61.41).

Sufficient knowledge about a given site may warrant the use of site-specific assumptions which may differ from the defaults. Exceeding a generic DCC usually suggests that further evaluation of the potential risks is appropriate. The DCC concentrations presented on this website can be used to determine compliance with dose limits in requirements that are determined to be an ARAR at that site.

CERCLA is NOT a Dose-Based Program

It is EPA's recommendation that dose assessments should only be conducted under CERCLA where necessary to demonstrate ARAR compliance. Further, dose recommendations in guidance should generally not be used as to-be-considered material. For more information on this issue, please see questions 33 and 36 on pages 27 to 29 of "Radiation Risk Assessment At CERCLA Sites: Q & A" (EPA 540-R-012-13, May 2014).

Also, EPA generally does not use ARARs greater than 12 mrem/yr to establish cleanup levels at CERCLA sites. Cleanup levels not based on an ARAR should be based on the carcinogenic risk range (generally 10^-4 to 10^-6, with 10^-6 as the point of departure and 1 x 10^-6 used for PRGs). For further guidance on this issue, refer to question 35 on page 28 of "Radiation Risk Assessment At CERCLA Sites: Q & A" (EPA 540-R-012-13, May 2014).

Related CERCLA Calculators and Guidance

It should also be noted that calculating a DCC does not address human cancer risk, noncancer toxicity, or potential ecological risk. Of the radionuclides generally found at CERCLA sites, only uranium has potentially significant noncancer toxicity. When assessing sites with uranium as a contaminant, it may also be necessary to consider the noncancer toxicity of uranium using other tools, such as EPA's Regional Screening Levels (RSLs) for Chemical Contaminants at Superfund Sites electronic calculator for uranium in soil, water, or air and the WTC for uranium inside buildings. EPA's SDCC Calculator should be used to assess radionuclide dose for hard outside surfaces, and the BDCC Calculator for radionuclide dose inside buildings. EPA's PRG Calculator should be used to assess radionuclide cancer risk for soil, water, and air; BPRG Calculator for radionuclide cancer risk inside buildings; and the SPRG Calculator for radionuclide cancer risk for hard outside surfaces. For sites where vapor intrusion may be of concern, the EPA's Vapor Intrusion Screening Levels (VISL) Calculator for chemicals should be consulted and for sites with radon, the Radon Vapor Intrusion Screening Level (RVISL) Calculator for Radionuclide Contaminants at Superfund Sites should be consulted. Similarly, some sites with radiological contaminants in sensitive ecological settings may also need to be evaluated for potential ecological risk. EPA's guidance "Ecological Risk Assessment Guidance for Superfund: Process for Designing and Conducting Ecological Risk Assessment" contains an eight step process for using benchmarks for ecological effects in the remedy selection process.

Below is a table that summarizes the existing EPA online calculators for assessing risks from chemicals and radionuclides at Superfund sites.