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Superfund Chemical Data Matrix (SCDM)

The Superfund Chemical Data Matrix (SCDM) is a source for factor values and benchmark values applied when evaluating potential National Priorities List (NPL) sites using the Hazard Ranking System (HRS). Factor values are part of the HRS mathematical equation for determining the relative threat posed by a hazardous waste site and reflect hazardous substance characteristics, such as toxicity and persistence in the environment, substance mobility and potential for bioaccumulation. Benchmarks are environment- or health-based substance concentration limits, including some developed by or used in other EPA regulatory programs. SCDM contains HRS factor values and benchmark values for hazardous substances that are frequently found at sites evaluated using the HRS, as well as the physical, chemical and radiological data used to calculate those values. The accompanying SCDM Methodology report describes how data are selected or calculated for inclusion in SCDM and how SCDM data, HRS factor values and benchmarks are presented in formatted printouts.

On January 28, 2004, the EPA released an updated SCDM with many revisions to the HRS factor values and benchmarks. These revisions were necessary both because of updates in the SCDM procedures used to assign HRS factor values and benchmarks and because of revisions to pertinent standards and criteria for individual hazardous substances and their associated characteristics.

UPDATE: On December 1, 2011, the EPA released updated human toxicity factor values and air inhalation benchmarks for 49 volatile substances listed in SCDM. Click here for a list of affected contaminants, updated values, and a description of procedures used to determine the updated values: December 2011 SCDM Volatile Substances. These updated values reflect current reference source information, as well as updates in the procedures for determining human toxicity factor values and air inhalation benchmarks.

UPDATE: On February 6, 2012, the EPA released updated screening concentration benchmarks for trichloroethylene (TCE) in air, drinking water, ground water, soil and human food chain exposure pathways. Click here for the updated values and a description of the procedures used to determine the updated values.

UPDATE: On March 31, 2012, the EPA released updated data factor values, screening concentration benchmarks and chemical/physical properties for 49 volatile substances listed in SCDM. Click here for a list of affected contaminants, updated values and a description of the procedures used to determine the updated information. This update supercedes information provided in the December 2011 update.


Disclaimer

The Superfund Chemical Data Matrix (SCDM) is a database containing factor values and benchmark values used for applying the Hazard Ranking System (HRS) [40 CFR Part 300 Appendix A, 55 FR 51583] to evaluate potential National Priorities List (NPL) sites. The physical, chemical, toxicological and radiological parameters used to calculate the factor values and benchmarks contained in SCDM are obtained from references listed in Chapters 2 and 3 of the SCDM Methodology. The references and the data extracted from them were selected to meet specific HRS requirements and conditions which may not be applicable or representative for other uses. In addition, the parameter values are updated only on an "as needed" basis. As a screening tool, the HRS and SCDM are used for quickly assessing sites at the screening stage and data used to perform this task may not be applicable for other site specific purposes.

The parameter values in SCDM should be used for HRS and NPL purposes only.


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Superfund Chemical Data Matrix Report

March 2012 Volatile Substances: Acenaphthene; Acetone; Acrolein; Anthracene; Benzene; Bromodichloromethane; Carbon disulfide; Carbon tetrachloride; Chlorobenzene; Chloroform; Cumene; Dibensofuran; 1,2-Dibromo-3-chloropropane; 1,2-Dibromoethane; 1,4-Dichlorobenzene; 1,1-Dichlroethane; 1,2-Dichloroethane; 1,2-Dichloroethylene; 1,2-Dichloroethylene (mixed isomers); 1,2-cis-Dichloroethylene; 1,2-trans-Dichloroethylene; 1,2-Dichloropropane; 1,3-Dichloropropene; Ethylbenzene; Fluorene; Mercury (elemental); Methyl ethyl ketone (2-butanone); Methyl tert-butyl ether; Methylene chloride; Nitrobenzene; 2-Methylnaphthalene; Naphthalene; Pyrene; Styrene; 1,1,2,2-Tetrachloroethane; Tetrachloroethylene; Toluene; 1,2,4-Trichlorobenzene; 1,1,1-Trichloroethane; 1,1,2-Trichloroethane; Trichloroethylene; Trichlorofluoromethane; 1,2,3-Trichloropropane; Vinyl acetate; Vinyl chloride; p-Xylene; m-Xylene; o-Xylene; Xylenes

Please note that the January 2004 SCDM was developed by compiling a list of CERCLA hazardous substances used in the scoring of NPL sites since 1990. The previous SCDM versions were developed using all substances ever scored at a site using the original HRS. The January 2004 SCDM does not include any substance that has not been used in the scoring of a site since 1990, even if previously listed in SCDM.

There are 17 new entries (PDF) (1 pg, 41K) (with new CAS Numbers) in the January 2004 version of SCDM that were not in the 1996 version. There are 235 fewer entries (PDF) (5 pp, 58K). Some of these changes resulted from new naming conventions and more specific identification of isomers and congeners. Also, some substances were removed because they were pollutants and contaminants and not Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) hazardous substances.

NOTE: Please do not assume that any substance not listed in the January 2004 SCDM cannot be used for HRS scoring. The number of entries was reduced to save resources in developing, updating and tracking changes in chemical properties. If values are needed for a substance that was not listed in the January 2004 SCDM and are thought to be critical to the listing decision, please request the value by calling the SCDM contact listed below. As a preliminary value (for screening purposes only), the former 1996 value associated with the substance can be used, and the EPA will verify the new value if necessary. For all technical questions concerning SCDM, please contact the contact listed below.

For SCDM information, contact:
Linda Gaines, Ph.D., P.E. (gaines.linda@epa.gov)
US Environmental Protection Agency
1200 Pennsylvania Avenue, N.W.
Washington, DC 20460
Phone: (703) 603-7189
Email: gaines.linda@epa.gov

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