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DCC Frequently Asked Questions (FAQ)

This page presents many questions asked by site users and responses. Please search this page for answers to your questions prior to contacting technical support staff. Researching the questions and answers posted here will greatly reduce the time it takes for you to solve many problems that arise from calculating and using this DCC site.

  1. What are DCCs?
  2. What are DCCs used for?
  3. What are radionuclide dose conversion factors (DCF)?
  4. How should dose conversion factors (DCFs) be used?
  5. How do DCCs differ from Removal Action Levels (RALs)?
  6. How do DCCs differ from cleanup standards?
  7. How often do you update the DCC Table?
  8. Can I get a copy of a previous DCC table?
  9. What ages and exposure routes are considered in each land use?
  10. How can I select more than one isotope at a time in the DCC Search page?
  11. How are the DCC results converted to a mass basis?
  12. How are the residential exposure durations (EDs) used in the DCC equations determined for carcinogenic (age-adjusted) exposures?
  13. How can I get the calculator results or the other web pages to print on one page?
  14. Do the fish tissue and/or soil DCCs apply to wet-weight or dry-weight data?
  15. Do the DCCs take into account field survey or laboratory analytical approaches?
  16. Are the DCCs applicable to cleanup after a terrorist attack?
  17. Do the DCCs factor inhalation from Radon vapor intrusion?
  18. What is the preferred citation for information taken from this website?
  19. Where else can I go for toxicity studies (values) not on this site?
  1. What are DCCs?
  2. The recommended DCCs (Dose Compliance Concentrations for Radionuclides in Buildings) presented on this site are dose-based concentrations, derived from standardized equations combining exposure information assumptions with EPA dose conversion factors, that are used for Superfund/RCRA programs. They are designed by the Agency to achieve protective cleanup levels for humans (including sensitive groups) over a lifetime. Recommended DCCs are not always applicable to a particular site, however, and do not address non-human health endpoints such as ecological impacts. The recommended DCCs contained in the DCC table are generic; that is, they are calculated without site-specific information. They may be re-calculated using site-specific data.

  3. What are DCCs used for?
  4. DCCs often are used for site "screening" and as initial cleanup goals, if appropriate. The recommended DCCs on this site are not de facto cleanup standards and should not be applied as such. The recommended DCC's role in site "screening" is typically to help identify areas, contaminants, and conditions that do not require further federal attention at a particular site. Generally, at sites where contaminant concentrations fall below DCCs, no further action or study is warranted under the Superfund program, so long as the exposure assumptions at a site match those taken into account by the DCC calculations. Radionuclide concentrations above the DCC would not automatically designate a site as "dirty" or trigger a response action. Exceeding a DCC suggests that further evaluation of the potential risks that may be posed by site contaminants is appropriate. DCCs may also be useful tools for identifying initial cleanup goals at a site. In this role, DCCs can provide long-term targets to use during the analysis of different remedial alternatives. By developing DCCs early in the decision-making process, design staff may be able to streamline the consideration of remedial alternatives.

  5. What are radionuclide dose conversion factors?
  6. 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 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, which are included in this DCC electronic calculator. 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.

  7. How should dose conversion factors be used?
  8. The primary use of DCFs is to compare doses from site-related exposures with radiation protection standards and dose limits that are determined to be ARARs. This is accomplished by multiplying the exposure estimates (i.e., the intake of each radionuclide of concern via inhalation and ingestion and the duration of exposure and concentration of each radionuclide of concern in environmental media for external exposure) by the appropriate DCF values for that exposure pathway and radionuclide. Unlike excess cancer risk, which represents cumulative lifetime exposure, dose estimates are typically expressed in terms of annual exposure (e.g., the effective dose equivalent resulting from exposure during a one-year period, mrem/year).

  9. What dose-based radiation standards may be applicable or relevant and appropriate requirements (ARARs)?
  10. In some cases, cleanup levels may be derived based on compliance with ARARs. Attachment A, "Likely Federal Radiation Applicable or Relevant and Appropriate Requirements (ARARs)", of OSWER Directive 9200.4-18 (U.S. EPA 1997a) provides guidance to use federal standards that have often been selected as ARARs that may be either applicable or relevant and appropriate for particular site-specific conditions. NOTE: EPA has determined that NRC decommissioning requirements (e.g., 25 or 100 mrem/yr dose limits) under 10 CFR 20 Subpart E should generally not be used to establish cleanup levels under CERCLA, even when these regulations are ARARs.

  11. How do DCCs differ from cleanup standards?
  12. DCCs are not designed to serve as de facto cleanup standards; however, they could be used to help establish final cleanup levels for a site after a proper evaluation takes place. In the Superfund remedial program, part of this evaluation typically is carried out as part of the nine criteria analysis for remedy selection, addressed in the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). The site-specific cleanup level, which can be based in part on DCCs, is documented in the Record of Decision.

  13. How often do you update the DCC Table?
  14. The recommended DCC database is typically updated when new toxicity values are presented by the EPA. This is generally done monthly; however, there may be times when more than one month passes without the release of updated toxicity values. Please take note of the "What's New" page to identify when toxicity values are updated.

  15. Can I get a copy of a previous DCC table?
  16. We do not distribute outdated copies of the recommended DCC table. Each new version of the table supersedes all previous versions. If you wish to maintain previous versions of the DCCs for a long-term project, you can download the entire table and save multiple versions with a time-stamp.

  17. What ages and exposure routes are considered in each land use?

    The following table lists the land uses, media, and receptor ages utilized in the DCC calculator.

    Land use Media Exposure Routes
    Oral Externala Inhalation
    Resident Soil Adult
    Child
    Adult
    Child
    All Ages
    Tapwater Adult
    Child
    Adult
    Child
    All Ages
    Air NA All Ages Adult
    Child
    Fish All Ages NA NA
    Recreator Soil/Sediment Adult
    Child
    Adult
    Child
    All Ages
    Surface Water Adult
    Child
    Adult
    Child
    NA
    Air NA All Ages Adult
    Child
    Game & Fowl
    Consumption
    All Ages NA NA
    Farmer Soil Adult
    Child
    Adult
    Child
    All Ages
    Tapwater Adult
    Child
    Adult
    Child
    All Ages
    Air NA All Ages Adult
    Child
    Biota
    Consumption
    Adult
    Child
    NA NA
    Outdoor Worker Soil Adult Adult Adult
    Air NA Adult Adult
    Indoor Worker Soil Adult Adult Adult
    Air NA Adult Adult
    Composite Worker Soil Adult Adult Adult
    Air NA Adult Adult
    Construction Worker Soil Adult Adult Adult
    Air NA Adult Adult
    Soil to Groundwater Soil Adult
    Child
    Adult
    Child
    All Ages

    NA = Not Applicable
    a. The external exposure routes include external exposure to ionizing radiation in soil, submersion in air, and immersion in water.

  18. How can I select more than one isotope at a time in the DCC Search page?

    To select more than one isotope you can:

    1. Left click and hold the button down while dragging the mouse pointer up and down through the isotope list,
    2. Hold the control (Ctrl) key down while left clicking on the isotopes desired, or
    3. Click in the "Select All" box to the bottom right of the isotope list.
  19. How are the DCC results converted to a mass basis?

    Appendix B of the Soil Screening Guidance for Radionuclides Technical Background Document presents a formula for converting DCCs in pCi/g to mg/kg and also a formula for converting pCi/L to mg/L. The equation is reproduced here with similar conversions for mg/m3 and mg/cm2.


    The derivation of the 2.8 × 10-12 and the 2.8 × 10-15 conversions are presented below.


    Combination of the derivation of the conversions with the isotope-specific half life and atomic weight is presented here.


  20. How can I get the calculator results or the other web pages to print on one page?

    Output links for PDF and Spreadsheet files can be found at the top of the calculator results page. The HTML results are not suited for formatting to print on a single page but are rather designed for ease of use on the screen.

  21. Do the fish tissue and/or soil DCCs apply to wet-weight or dry-weight data?

    The fish DCCs represent the concentration that can be consumed at the rate indicated in the Technical Background Document. Therefore, wet or dry weight is not an inherent assumption of the DCC numbers. Rather, users of the Table should consider whether their population of interest is more likely to consume the fish using a preparation method that is better simulated by a wet or dry weight. (For example, consumption of raw or fried fish would be more likely represented by wet weight, whereas consumption of smoked or dried fish might be better represented by dry weight.) In other words, the use of a site-specific sample as wet or dry weight should be governed by its representativeness for the population of interest. The DCC Calculator does not provide default fish DCCs under residential. If the fish scenario is selected under residential, the calculator will automatically switch to site-specific mode. On the next page, the user is required to enter a site-specific fish consumption rate. The previous default fish intake rate of 54,000 mg/day from the Standard Default Exposure Factors has been removed. Intake rates can be found in the 2011 Exposure Factors Handbook. Please consult your Regional risk assessor when determining appropriate fish consumption rates. The soil DCCs are based on dry weight, because the soil intake rates are based on dry weight. Most soil data is typically reported as dry weight. As always, please consult your Regional risk assessor when applying the DCCs to site-specific data.

  22. Do the DCCs take into account field survey or laboratory analytical approaches?

    No, the DCCs are a dose-based tool only, except for the Soil to Groundwater scenario, which is usually based on MCLs. Determining the extent of contamination is a separate process during the Remedial Investigation or Feasibility Study (RI/FS) and remedial design processes. It is important for remedial decision data to be of known and acceptable quality. The determination of what data are needed is a site-specific decision, and it is the responsibility of the Remedial Project Manager (RPM) to use the tools that are most appropriate for that situation.

  23. Are the DCCs applicable to cleanup after a terrorist attack?

    Responses to radiological and nuclear terrorist incidents is addressed in an August 1, 2008, guidance issued by the Department of Homeland Security (DHS) in the Federal Register (Vol. 73, No. 149, pp 45029 - 45049), Planning Guidance for Protection and Recovery Following Radiological Dispersal Device (RDD) and Improvised Nuclear Device (IND) Incident. The DHS guidance uses Operational Guidelines from the Department of Energy to guide the early and intermediate phases of response to an RDD and an IND. Under the guidance, the late-phase generally would utilize an optimization process to site-specifically decide on an approach for addressing the remaining residual contamination. Normally, the DCC calculator would be used only if the optimal process for the late-phase was a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) approach. As at a CERCLA site, the user at an RDD or IND site can choose to modify the standard default DCC exposure parameters to calculate site-specific DCCs. The characteristics of an RDD or IND site may warrant the use of site-specific assumptions that differ from the DCC defaults. The site manager should weigh the cost of collecting the data necessary to develop site-specific DCCs with the potential for deriving a higher DCC that provides an appropriate level of protection.

  24. Do the DCCs factor inhalation from Radon vapor intrusion?

    Air DCCs represent preliminary remediation goals for indoor and outdoor air. The residential and industrial air DCC values can be used to determine preliminary remediation goals that are detected in the air (e.g., indoor and outdoor) from a variety of sources. There are no DCCs specific to the vapor intrusion pathway (i.e, for subsurface sources that may contribute to indoor air contamination). EPA's recommended Radon Vapor Intrusion Screening Level tool can be found online here. For guidance on vapor intrusion assessment, see EPA's Vapor Intrusion Site. The OSWER Technical Guide For Assessing And Mitigating The Vapor Intrusion Pathway From Subsurface Vapor Sources To Indoor Air (OSWER Publication 9200.2-154; June 2015) can be found there among other resources and information.

  25. What is the preferred citation for information taken from this website?

    United States Environmental Protection Agency. Dose Compliance Concentrations for Radionuclide Contaminants at Superfund Sites. (insert date accessed and url).

  26. Where else can I go for toxicity studies (values) not on this site?

    Many other websites host toxicity information from other countries and other government agencies similar to this EPA site. The Risk Assessment Information System (RAIS) at http://rais.ornl.gov/ presents toxicity values and toxicity study information. Websites of other governmental agencies are also useful. Call the U.S. EPA Superfund Health Risk Technical Support Center at (513) 569-7300 and ask for toxicity values. Call the ATSDR Information Center toll-free at 1-888-422-8737 for toxicity values and profiles.