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Waste and Cleanup Risk Assessment

Health Effects Assessment Summary Tables for Superfund (HEAST)

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Contents

HEAST On-line Repository


Current as of December 2011

Office of Research and Development
Office of Emergency and Remedial Response
U.S. Environmental Protection Agency
Washington, DC 20460

DISCLAIMER

This document has been prepared by the U.S. Environmental Protection Agency (EPA). The information contained herein has been taken from final documents prepared by or for the National Center for Environmental Assessment (NCEA) for the Office of Solid Waste and Emergency Response (OSWER), the Office Air and Radiation (OAR), the Office of Water, and the Office of Air Quality Planning and Standards (OAQPS). These documents were reviewed in accordance with Agency policy and approved for publication. They have variuos levels of peer review that were deemed appropriate at the time of development.

INTRODUCTION

The Health Effects Assessment Summary Tables (HEAST) is a database of human health toxicity values developed for the EPA Superfund and Resource Conservation and Recovery Act (RCRA) hazardous waste programs. Until the early to mid-1990s, HEAST was updated on a regular basis and was known as the Quarterly, reflecting its publication by EPA four times per year.

HIERARCHY OF HUMAN HEALTH TOXICITY VALUE SOURCES

It is recognized that at any point in time there may be multiple old and new Agency documents or databases that present different values for a specific contaminant. The following hierarchy of sources is recommended in evaluating chemical toxicity for Superfund sites:

  • Integrated Risk Information System (IRIS) and cited references. Changes are made in this database as new chemicals or chemical information becomes available, but there may be data gaps. Visit http://www.epa.gov/iris/ or call the IRIS HOTLINE at (301) 345-2870 for further information.
  • The Provisional Peer Reviewed Toxicity Values (PPRTV) and cited references developed for the EPA OSWER Office of Superfund Remediation and Technology Innovation (OSRTI) programs.1
  • Other toxicity values.2

The "other" level of the hierarchy includes several sources of toxicity values that are commonly consulted by the EPA Superfund program when a relevant toxicity value is not available from either IRIS or the PPRTV database. They include:

  • California Environmental Protection Agency (Cal EPA) toxicity values, available on Cal EPA's internet website at http://www.oehha.ca.gov/risk/chemicalDB/index.asp;
  • The Agency for Toxic Substances and Disease Registry (ATSDR) Minimal Risk Levels (MRLs, addressing noncancer effects only), available on ATSDR's internet website at http://www.atsdr.cdc.gov/mrls.html ;
  • The EPA Superfund Health Effects Assessment Summary Tables (HEAST) database and cited references; and
  • Additional sources of toxicity values.

Note: Do not consult either the toxicity tables (Appendix A) in the Superfund Public Health Evaluation Manual (SPHEM, U.S. EPA, 1986) or the September 1988 Public Health Risk Evaluation Data Base (PHRED); these sources were superceded as guidance by Risk Assessment Guidance for Superfund, 1989 (RAGS) and are likely to contain numerous values that have since become out-of-date.

Both RCRA and Superfund hazardous waste programs accept the primacy of human health toxicity values contained in IRIS. Toxicity values placed on IRIS have undergone Agency consensus review. When HEAST was being published on a quarterly basis, if a new toxicity value was placed on IRIS, the corresponding value was removed from HEAST. Beginning in 2002, as HEAST toxicity values are replaced with new provisional peer-reviewed toxicity values (PPRTVs), the corresponding value will be removed from HEAST, and the PPRTV will be placed in the PPRTV database.

HEAST ORGANIZATION

Staff in regional Superfund and RCRA program offices are advised to carefully review the information provided on HEAST to ensure that any HEAST toxicity value used is appropriate for the types of exposures and circumstances at the Superfund site or RCRA facility in question. Contact the NCEA Superfund Health Risk Technical Support Center (STSC) or the appropriate personnel in OSWER with questions about HEAST toxicity values and their appropriate use.

This HEAST database is primarily an electronic format of the HEAST FY 1997 Update. HEAST Tables 1, 2 and 3 from the 1997 Update were consolidated into an electronic, searchable format. The user selects either a chemical abstract series registration number (CASRN) or a chemical name from the alphabetical index. All of the HEAST contaminant-specific information for subchronic and chronic noncancer toxicity, alternate methods for toxicity, and toxicity values for carcinogenicity (i.e., slope factors and unit risk values) are shown in different sections. Each section also shows the appropriate references.

As of August 2002, HEAST contains human health toxicological information for approximately 400 contaminants, including (cancer and noncancer) toxicity values and study (laboratory and epidemiological) information and references. The searchable database contains toxicity information only on chemicals. Slope factors on radionuclides are calculated by the Office of Air and Radiation (OAR) and are presented in the HEAST database in the Table 4 format of the 1997 HEAST Update and on OAR's website: http://www.epa.gov/radiation/heast/download.htm.

CAUTION

The toxicity values [other than National Ambient Air Quality Standards (NAAQS) or Drinking Water Criteria Documents (DWCD) values] in this database are considered to be "provisional". The Agency has no official definition for this term, but the user may interpret it as follows: A toxicity value or a cancer value is "provisional" if the value has had some limited form of Agency or external review but does not have the extensive documentation or formal review process required for inclusion on IRIS. The PPRTVs developed for the Superfund Program, and described under Appendix A - Technical Information of this introduction, are another form of non-IRIS toxicity values. Please note that the PPRTVs have undergone external peer review before they are placed in that database.

The user is referred to the IRIS database for Agency Consensus toxicity values. It is also important for users to note the development date of toxicity values in these databases. For IRIS values, all available information on the contaminant at that time was evaluated, the value was calculated using the methodology current at the time, and an Agency consensus was reached on the value. The values in the HEAST database have NOT undergone a full Agency Consensus review.

It is also important to remember that the numbers alone tell very little about the adverse effects of a chemical or the quality of evidence on which risk assessment information is based. Original assessment documents should be consulted in order to fully appreciate the strengths and limitations of a specific toxicity value and to develop a full risk characterization. Original source documents will allow for the most complete characterization of potential toxicity associated with the range of exposure pathways generally evaluated at Superfund sites and RCRA facilities. The references listed in HEAST point the user to these sources for HEAST values.

CONTRIBUTORS

Contaminants commonly found at Superfund sites and RCRA facilities, as identified by the Office of Solid Waste (OSW), are included in HEAST. The OAR calculated the radionuclide slope factors presented in Table 4. Finally, the OAQPS has provided information on chemicals for which Air Quality Criteria Documents and National Ambient Air Quality Standards have been developed.

CONTAMINANTS LISTED

Most of the contaminants included are those for which at least one of the following EPA documents has been written: Health Effects Assessment Document (HEA), Health and Environmental Effects Profile (HEEP), Health and Environmental Effects Document (HEED), Health Assessment Document (HAD), Air Quality Criteria Document (AQCD), and/or Drinking Water Criteria Document (DWCD). A description of each is provided in Appendix A, Section I. In a few cases, the values are supported by other written material, such as reference dose (RfD)/reference concentration (RfC) and Carcinogen Review and Verification Endeavor (CRAVE) Workgroup3 meeting notes completed as IRIS assessments or Carcinogen Assessment Group (CAG) Profiles. Most of these documents were written in the late 1980s and early 1990s. The Radionuclide slope factor values, which were calculated by the EPA OAR program, were updated in 2000.

The names of criteria pollutants that are regulated as NAAQS under the Clean Air Act are listed in the main body of the HEAST, but the actual criteria are included as Section V of Appendix A. NAAQS were not included in the summaries in order to distinguish them from the inhalation reference concentration (RfC) values. The NAAQS and RfCs represent different levels of review and different methods of calculation and thus must be interpreted and used differently.

QUESTIONS

Chemical Toxicity and Carcinogenicity

Questions regarding the contents of the chemical toxicity and carcinogenicity summaries in HEAST or the PPRTVs (e.g., contaminants not covered or contaminants with pending reference values) may be directed to EPA/ORD/NCEA/STSC in Cincinnati, OH at (513)569-7300 [FAX#: (513)569-7159]. Requests should include the following information:

  • Superfund site name, site location, twelve-digit CERCLIS4 site number, and Federal Facility Status;
  • Name and phone number of the site Remedial Project Manager (RPM) On-Scene Coordinator OSC) or Regional Risk Assessor/Toxicologist;
  • Detailed description of the risk assessment related question.

Written requests should be mailed to:

Superfund Health Risk Technical Support Center
US EPA
26 W. Martin Luther King Dr.
National Center for Environmental Assessment
MS - G44
Cincinnati, OH 45268

Radionuclide Carcinogenicity

Questions concerning radionuclide carcinogenicity should first be addressed by contacting the appropriate Regional Radiation Program Manager. A revised listing of these managers and several contacts in OAR can be found in Exhibit 2 of the User's Guide - Radionuclide Carcinogenicity and on OAR's internet website at http://www.epa.gov/radiation.

REFERENCES

Most cited Agency references (e.g., HEAs, HEEPs, HEEDs) are available through the National Technical Information Service (NTIS), 5285 Port Royal Road, Springfield, VA 22161 [(703)487-4650].

Carcinogen Assessment Group (CAG) Profiles cited are available through the RCRA Docket, (703)603-9230.

Drinking water documents are available by calling the Water Resource Center at (202)260-7786.

STRUCTURE OF THE HEAST DATABASE

As of August 2002, the HEAST database provides human health risk assessment information for approximately 400 contaminants. This information is divided into five sections: 1) heading, 2) summary, 3) subchronic and chronic toxicity (other than carcinogenic), 4) alternate methods- subchronic and chronic toxicity (other than carcinogenic), and 5) carcinogenicity.

  • Heading

The database heading includes the chemical name, Chemical Abstract Series Registration Number (CASRN), molecular formula, molecular weight, and a link to a database, under the "Chemical Information" heading, to obtain a picture or schematic representation of the chemical structure, synonyms, etc.

  • Summary

The summary section lists the value(s) [e.g., chronic reference doses (RfDs)] that are presented on-line for subchronic and chronic toxicity, alternate methods - subchronic and chronic toxicity, and carcinogenicity. A link is provided to take the user directly to the value on that page. Additionally, the summary information may include links to IRIS.

Note: IRIS links are only provided for chemicals that have some type of information in the HEAST database. Chemicals that were previously listed in HEAST, but contained no toxicity information other than a referral to the IRIS database, have been removed from HEAST.

  • Subchronic and Chronic Toxicity (other than Carcinogenicity)

This section lists subchronic and chronic non-cancer toxicity values that were calculated using the methodology used by NCEA in the development of reference values for IRIS as well as information on the uncertainty factors, route of exposure, target organ/critical effect, study information, references, and comments.

  • Alternate Methods - Subchronic and Chronic Toxicity (Other Than Carcinogenicity)

This section lists subchronic and chronic non-cancer toxicity values that are found in Agency documents but were calculated by alternative methods that were not used by NCEA for IRIS, as well as information on the uncertainty factor, exposure route, target organ/critical effect, study information, references, and comments. These values are considered to be generally appropriate as provisional values for risk assessment purposes at Superfund sites and RCRA facilities, but should be reviewed to confirm that they appropriate for the types of exposures existing at a particular Superfund site or RCRA facility.

  • Carcinogenicity

This section lists carcinogenicity values that were calculated for HEAST using Agency methodology as well as information on the route of exposure, target organ/cancer, toxicity study information, EPA carcinogen class, references, and comments.

  • Radionuclide Carcinogenicity - Slope Factors (In Units of Picocuries)

This table provides ingestion, inhalation, and external exposure carcinogenicity slope factors for radionuclides in units of picocuries and a factor to convert to the International System (SI) activity units of becquerels (Bq).

  • Technical Appendix

A technical appendix (Technical Information) is available, containing the following sections:

  • Data Sources and Selection Criteria Used in HEAST
  • Dose Conversions on HEAST
  • CASRN Cross Reference
  • Effect Level Definitions
  • National Ambient Air Quality Standards (NAAQS), also available on an EPA website at http://www.epa.gov/airs/criteria.html.

ENDNOTES

1OSWER is issuing a new directive to present the revised hierarchy of toxicity value sources: IRIS, values from the PPRTV database, and other peer-reviewed values. Section 7.4 of Risk Assessment Guidance for Superfund (RAGS) Volume I, Human Health Evaluation Manual, Part A, (EPA/540/1-89/002) had previously identified the following hierarchy of toxicity value sources: IRIS, HEAST, EPA criteria documents, Agency for Toxic Substances and Disease Registry (ATSDR) Toxicological Profiles, EPA's Environmental Criteria and Assessment Office documents, and open literature.

2It is recommended to EPA toxicologists, risk assessors and risk managers in the Superfund program that they consult with NCEA/STSC regarding the use of any toxicity value from this level of the hierarchy (below IRIS and the NCEA/STSC PPRTVs), especially if the use of such a toxicity value is considered critical to the selection of a remedial or removal action at a Superfund site and if the contaminant is considered a "risk driver" for that site.

3EPA's RfD/RfC and CRAVE workgroups were discontinued in May 1995. Chemical substance reviews that were not completed by September 1995 were taken out of IRIS review. The IRIS Pilot Program replaced these workgroup functions beginning in September 1995.

4"Comprehensive Environmental Response, Compensation and Liability Information System", the database in which EPA maintains information about sites or releases being assessed as potential Superfund sites. Since all funding for the STSC comes from the Superfund Program, this center provides support only on Superfund sites, which is why a CERCLIS number is sought on requests for assistance from the STSC.

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