What's New

January 2017 Updates

The "Uranium Soluble Salts" PRG uses the ATSDR intermediate MRL of 2E-04 mg/kg-day instead of the IRIS oral RfD of 3E-03 mg/kg-day. This is a deviation from the typical toxicity hierarchy. " In December 2016, the EPA Office of Superfund Remediation and Technology Innovation (OSRTI) announced its determination that the ATSDR intermediate MRL generally reflects a better scientific basis for assessing the chronic health risks of soluble uranium than the RfD currently available in IRIS." The rationale for this determination is summarized in an accompanying memorandum, which recommends use of the ATSDR intermediate MRL for assessing chronic and subchronic human exposures at Superfund sites nationwide.

New inhalation Risk and Dose Coefficients are avilable for Rn-222, Rn-220, Bi-212, Bi-214, Pb-212, Pb-214, and Po-218.

Intake rates have been updated for recreator surface water ingestion according to Table 3.5 in the 2011 Exposure Factors Handbook.

December 2016 Updates

  • IRIS updates to Ethylene Oxide have been added.

October 2016 Updates

  • PPRTV updates to o-Phenylenediamine, o-Aminophenol, 1,2,3,4,5-Pentabromo-6-Chlorocyclohexane , 1,2-Dichloropropane, and 1,1,2-Trichloro-1,2,2-trifluoroethane have been added.
  • IRIS has archived 51 chemical assessments for pesticides and has recommended the use of the Office of Pesticide Programs (OPP) human health risk benchmarks for pesticides (HHBPs). OPP lists 363 pesticides. All pesticides currently in the RAIS database will now use the new RfDs and slope factors in the HHPB table and pesticides not currently in the RAIS database will be added as time permits. The OPP values are tier 3 and are used in our hierarchy after PPRTV and before ATSDR. The archived IRIS values will be retained in the RAIS database for historical reference and presented in the Chemical Data Profile Tool as soon as possible.

September 2016 Updates

  • The Indoor Worker water ingestion rate was updated to 1.25 L/day per OSWER Directive FAQ 13.
  • IRIS updates to ammonia and trimethylbemzenes have been added.
  • PPRTV updates to n-heptane, 2-mercaptobenzothiazole, rubidium, rubidium chloride, rubidium hydroxide, rubidium iodide, 3-methylphenol, N,N-dimethylaniline, and p-phenylenediamine have been added.
  • A link under the guidance tab has been added that lists all the Health and Environmental Agencies of U.S. States and Territories and provides contact information.

August 2016 Updates

  • The Koc values for PFOS and PFOA were updated. The values presented in the Health Advisories were presented as Koc but were actually log Koc values.

June 2016 Updates

  • The Chemical Data Profile Tool provides a look into all the available toxicity values and chemical parameters that are part of the RAIS databases. The RAIS uses a source selection hierarchy to determine what values are used in our risk calculations. The hierarchies are described in the PRG and Risk Models user’s guides. Explosive limits, critical values, molar enthalpies, atmospheric (OH) rate constants, acid dissociation constants and flammability parameters were added from multiple sources. The preferred values are now highlighted and a synonym list was added.
  • Chemicals with toxicity value changes due to Cal EPA updates are: Lead acetate, Toluene-2,4-diisocyanate, and Toluene-2,6-diisocyanate.
  • Chemicals with new toxicity values due to PPRTV updates are: Chloronitrobenzene and p-, Benzaldehyde.
  • Thallic oxide and thallium selenite RfDs were derived by MW adjustment.
  • The chemical name associated with CAS 114-26-1 was changed to Phenol, 2-(1-methylethoxy)-, methylcarbamate from Propanediol, 1,2-.
  • The programming of the soil to groundwater scenario was changed to allow the calculation of the SSL when H' is missing.
  • The programming of the diffusivity in air (Dia) equation was changed to use the dioxin-specific equation for furans and dioxin-like PCBs. See section 4.16.4 of the PRG User's Guide.
  • The hierarchy of Koc sources was modified to use the SSL first for the nine ionizable organics identified. See section 2.4.2 of the PRG User's Guide.
  • Various parameters have changed for Chlordane, Hydrogen cyanide, Cyanide (CN-) and White phosphorus.
  • Freezing point values from Yaws were added to the 6th position of the hierarchy.
  • The radiation risk calculator was updated to only allow inhalation of gases in tapwater.
  • The chromium VI oral slope factor from Cal EPA Consolidated Table of OEHHA/ARB Approved Risk Assessment Health Values was updated.

March 2016 Updates

  • The EPA Ecological Soil Screening Levels (Eco-SSL) for Copper were updated in the Ecological Benchmark Tool. The plant Eco-SSL values were removed for boron, fluorine, iodine, lithium, mercury, methyl mercury, molybdenum, technetium, thallium and tin. The invertebrate Eco-SSLs were removed for mercury and methyl mercury. These values incorrectly inferred as Eco-SSLs in the SQuiRTs.

December 2015 Updates

  • The EPA has released another update to the OSWER Directive concerning the use of exposure parameters from the Exposure Factors Handbook. Review the changes here. There you will find a new table and a FAQ explaining the changes. The child surface area for soil exposure and the worker surface area have been updated.

October 2015 Updates

  • PPRTV values have been updated for: 2-Chlorobenzoic Acid, 1,1-Dichloropropene, 2,4,4-Trimethylpentene, Carbonyl Sulfide, Diethylene Glycol Monomethyl Ether, 1,1,1-Trifluoroethane, Picric Acid, Lewisite, 1-Chlorooctadecane, Diundecyl phthalate, Ethyl Acrylate, Triethylene Glycol, Propylene Glycol Monoethyl ether - alpha isomer, Propylene Glycol Monoethyl ether - beta isomer, Isopropanol, 2-Methylphenol, Styrene-Acrylonitrile (SAN) Trimer, 1,3-Dibromobenzene, Perfluorobutane Sulfonate, and Potassium Perfluorobutane Sulfonate.

September 2015 Updates

  • MCLs for radionuclides have been updated.

June 2015 Updates

  • The definition of a volatile was changed to match the EPA RSL and VISL projects. The following criteria are now used to define a chemical as volatile in the RSLs: 1) vapor pressure greater than 1 mm Hg or 2) Henry's Law constant greater than 0.00001 atm-m3/mole. There are now over 100 chemicals newly classified as volatile. Chemical-specific parameters were added to the database for use in calculating volatilization factors for the new volatiles.

April 2015 Updates

  • The EPA has released an update to the OSWER Directive concerning the use of exposure parameters from the Exposure Factors Handbook. Review the changes here. There you will find a new table and a FAQ explaining the changes. The child surface area for soil exposure and the worker surface area have been updated.

October 2014 Updates

  • Ecological benchmark database was updated to restore the ECO-SSLs to match the Interim Eco SSLs found here rather than the values presented on the SQuiRTs table here.

September 2014 Updates

August 2014 Updates

  • The EPA has released a memo directing the use of new exposure parameters from the exposure factor handbook. The RAIS has incorporated these new parameters into the PRG and risk tools for chemicals. The radionuclide tools will be updated as soon as possible.

February 2014 Updates

  • A work around for the calculation of TCE PRGs for the resident has been implemented. The results that are given in default mode of the PRG calculator now match the EPA's regional screening level (RSL) tables. Details on the new equations are presented in the PRG USer Guide section 5.13.

November 2013 Updates

  • ECO mammalian SSLs were updated for cadmium, antimony , arsenic, inorganic, barium, Beryllium, chromium VI, cobalt, copper, lead, silver, vanadium, cyanide (total complex), methyl mercury, sulfide, thallium and tin.

October 2013 Updates

  • The biota intake rates for the radionuclide PRG and risk tools were updated to correct an improper units conversion.

September 2013 Updates

  • IRIS updates for 1,4-Dioxane and Biphenyl were completed.
  • PPRTV values have been updated for Biphenyl, 3,4-Dichlorobenzotrifluoride, Trinitrophenylmethylnitramine (Tetryl), Endosulfan Sulfate, 1,1,2,2-Tetrachloroethane, Nitromethane, Dibenzothiophene, 2-Ethoxyethanol, 3,3'-Dimethoxybenzidine, Butylated hydroxytoluene, Ethyl Acetate, tert-Amyl Alcohol, 2,2-Difluoropropane, 2,6-Dinitrotoluene, Dinitrotoluene Technical grade, Diisopropyl Methylphosphonate, Toluene-2-5-diamine and compounds, 1,4-Benzenediamine-2-methyl sulfate, 2-Methylbenzene-1,4-diamine sulfate, Toluene-2,5-diamine free-base, Toluene-2,5-diamine dihydrochloride, Toluene-2,5-diamine monohydrochloride and Methylcyclohexane. Appropriate chemical-specific parameters were added.
  • The download feature for the Chemical Toxicity Metadata and Ecological Screening Benchmark search tools were updated.
  • The Chemical Data Profile tool was updated.
  • The Ecological Screening Benchmark database was updated.

February 2013 Updates

We have recently incorporated the February 2013 update from ATSDR. It is:
  • The date of the final paper changed for: Tributyl Phosphate; respirable Manganese; Tricresol Phosphate (TCP); Tris(2-Butoxyethyl) phosphate (TBEP); Tris(2-chloroethyl) phosphate (TCEP); Tris(1,3-Dichloro-2-propyl) phosphate (TDCP); and Vanadium
  • Draft papers were removed (and values reverted to old values or additional draft values withdrawn) since they have not been cleared for publication for the following: 2,4-DNT; 2,6-DNT; Endosulfan; and Hexachlorobenzene.
  • Original values were removed and new addendum values were added for TCE.

January 2013 Updates

We have recently incorporated the January 2013 update from ATSDR. It is:
  • Acrylamide oral acute and intermediate values were changed from 0.02 and 0.002 to 0.1 and 0.001, respectively. Also, an oral chronic value of 0.001 was added.
We have recently incorporated the December 2012 updates from ATSDR. They are as follows:
  • 1,3-Butadiene has been removed from the database. (There was a draft inhalation acute value from 2009).
  • Cadmium values have changed from draft to final.
  • Chromium III soluble particulate values have changed from draft to final.
  • Chromium III insoluble particulate values have changed from draft to final.
  • Chromium VI oral chronic value has changed from 0.001 to 0.0009 and all values have changed from draft to final.
  • Chromium VI aerosol mist values have changed from draft to final.
  • Chromium VI particulate values have changed from draft to final.
  • 2,4-Dinitrotoluene values are draft as of Oct 2012. There is a new oral intermediate value proposed and the oral chronic value is changing from 0.002 to 0.001.
  • 2,6-Dinitrotoluene values are draft as of Oct 2012. There is a new oral acute value proposed.
  • 1,4-Dioxane inhalation intermediate, inhalation chronic, oral acute, and oral intermediate values have changed from 1, 1, 4, and 0.6 to 0.2, 0.03, 5, and 0.5, respectively. Also, all values have changed from draft to final.
  • Endosulfan values are draft as of Oct 2012. There is a new oral acute value proposed and the oral chronic value is changing from 0.002 to 0.005.
  • Hexachlorobenzene values are draft as of Oct 2012. The oral chronic value is changing from 0.00005 to 0.00007.
  • Manganese, respirable inhalation chronic value has changed from 0.04 to 0.3 and from draft to final.
  • Tributyl phosphate oral intermediate and oral chronic values have both changed from 0.02 to 0.08, and all values have changed from draft to final.
  • Tricresyl phosphate (TCP) has been added to the database as a new chemical with final values for oral intermediate and oral chronic.
  • Tris(2-butoxyethanol) phosphate (TBEP) oral intermediate value has changed from 0.2 to 0.09 and from draft to final.
  • Tris(2-cchloroethyl) phosphate (TCEP) oral chronic value has changed from 0.3 to 0.2 and from draft to final.
  • Tris(1,3-dichloro-2-propyl) phosphate (TDCP) values have changed from draft to final.
  • Vanadium values have changed from draft to final.

December 2012 Updates

Two new tools were added to the bottom of the TOOLS drop down menu on the blue horizontal navigation bar. The Groundwater Transport Calculator allows the user to enter a concentration in soil of a chemical, metal or radionuclide and calculate the resulting concentration in groundwater. Many site-specific soil and aquifer parameters are required. The user can choose between a partitioning model and a mass limit model. The Air Transport Calculator allows the user to enter a soil concentration of a radionuclide or nonradionuclide and calculate an air concentration based on site-specific meteorological conditions. The user can choose between a wind-driven or mechanically-driven model.

November 2012 Updates

The following changes were made as part of the semiannual RSL updates:

  1. The hydrogen cyanide RfC was also assigned to cyanide. Further, the cyanide Kd was also assigned to hydrogen cyanide. This will allow for calculation of a Csat and protection of groundwater SSLs.
  2. Chemicals with new toxicity values due to PPRTV updates are:
    • acetone cyanohydrin,
    • boron trichloride
    • chloroethanol, 2-,
    • cyclohexene,
    • diethanolamine,
    • ethylene cyanohydrin,
    • methacrylonitrile,
    • methyl acrylate,
    • octyl phthalate, di-N-,
    • thallium acetate,
    • thallium carbonate,
    • thallium chloride,
    • thallium (I) nitrate,
    • thallium sulfate,
    • thiocyanate,
    • toluene-2,5-diamine,
    • toluidine, p-,
    • triacetin,
    • tris(1-chloro-2-propyl)phosphate and
    • zirconium.
  3. The RfC for mercuric chloride was replaced with the IRIS RfC for elemental mercury.
  4. Changes in chemical-specific parameters were also made. The most significant change was updating the hierarchy of sources for water solubility as it was discovered that some sources were more qualitative than assumed.
  5. Thiocyanate was reclassified as an inorganic compound to be equivalent to all the other cyanide compounds.
  6. Changes were also made to the parameters involved in dermal exposure to water. Our previous hierarchy used RAGS Part E before using EPI for EPD (effective predictive domain) determination and Kp (dermal permeability) values. Recently released logKows (logp) for some chemicals conflicted with those in RAGS Part E. Specifically for the RSL project, the most recent logKow were used to determine EPD status. To complete the transition the RAIS now also calculates our own FA (fraction absorbed) values.
  7. To calculate a Csat, the ambient state of the VOC in soil must be known. As indicated in the SSL Guidance, Csat is not calculated for a chemical that is solid at soil temperatures. To make sure this rule was being followed, the melting point database was updated and this rule was established from the SSL guidance: if melting point is less than 20 °C, chemical is a liquid; if melting point is above 20 °C, chemical is solid.
  8. The individual TPHs (total petroleum hydrocarbons) are now available in the pick lists.
  9. MCLs were added for the following:
    • aldicarb,
    • aldicarb sulfone and
    • aldicarb sulfoxide.
  10. September 2012 Updates

    National Recommended Water Quality Criteria for Aquatic Life and MCLs were updated in the ARAR Search Tool.

    All Tennessee ARARs were updated.

    August 2012 Updates

    Canadian Water Quality Guidelines for surface water for the protection of aquatic life have been updated.

    May 2012 Updates

    The radionuclide decay chain tool has been updated to include more recent decay information from ICRP 107.

    April 2012 Updates

    The IRIS oral chronic reference doses for calcium cyanide, cyanogen, potassium cyanide, potassium silver cyanide, aqueous HCN and sodium cyanide were updated. The toxicity values for these analytes are based on the "Hydrogen Cyanide and Cyanide Salts (CASRN Various)" profile which was updated in 2010.

    February 2012 Updates

    The toxicity values for TCDD, Tetrahydrofuran and Tetrachloroethylene have been updated in IRIS.

    December 2011 Updates

    The toxicity values for Methylene Chloride (Dichloromethane) from IRIS have been updated. Methylene Chloride is now a mutagen. Hexachloroethane and Trichloroacetic Acid were also added from IRIS.

    Acrylamide is now treated as a mutagen.

    The Vanadium Sulfate RfD was dropped from HEAST.

    The RSL Website provides instructions on how to calculate PRGs for TCE for landuses involving multiple age cohorts.

    October 2011 Updates

    The toxicity values for TCE from IRIS have been added to the RAIS. TCE has now been classified as a mutagen. The RAIS mutagen equations only have 4 age bins yet the IRIS profile suggests 13. Also, the IRIS profile suggest that the liver, kidney and non-Hodgkin lymphoma risk be assessed separately and summed. The RAIS is not currently programmed for this level of detail. We will be watching the RSLs and will follow their lead.

    The Chemical Metadata Tool was updated to follow the RAIS chemical toxicity source hierarchy. The output now includes the toxicity value and it's reference as well as all the metadata contained on the RAIS. The result of this update allows the user to run PRG and risk calculations for COPCs and then pull the metadata for the toxicity values used in the PRG and risk calculations for the COPCs. Caution: if toxicity values are changed for PRG and risk calculations in the "user-provided" mode, then the metadata will not match.

    The Chemical PRG Tool and User Guide were updated to include RAGS Part E dermal exposure to water equations. This update also expanded the noncancer output to include child, adult and age-adjusted results. The site-specific option of the calculator now presents four age bins that are analogous to the mutagenic equation age bins. The 0-2 and 2-6 year age bins are combined to generate the traditional child exposure parameters and the 6-16 and 16-30 age bins are combined to generate the traditional adult exposure parameters. These age divisions are available for the resident and recretor scenarios.

    The Chemical Risk Tool and User Guide were updated to include RAGS Part E dermal exposure to water equations. This update also expanded the noncancer output to include child, adult and age-adjusted results. The site-specific option of the calculator now presents four age bins that are analogous to the mutagenic equation age bins. The 0-2 and 2-6 year age bins are combined to generate the traditional child exposure parameters and the 6-16 and 16-30 age bins are combined to generate the traditional adult exposure parameters. These age divisions are available for the resident and recreator scenarios.

    Both the chemical PRG and risk tools now give the user the option to select between chronic and subchronic noncancer toxicity values.

    The Chemical Data Profile Tool was updated to include more metadata.

    July 2011 Updates

    Some Toxicity Profiles were updated to correct .html usage of special characters.

    June 2011 Updates

    The Risk Assessment Overview Diagram was updated.

    The Chemical Data Profile Tool was updated.

    New PPRTVswere added to the toxicity database.

    November 2010 Updates

    EPA Eco-SSLs are updated.

    October 2010 Updates

    New toxicity values and metadata have been uploaded for Chloroprene (Chloro-1,3-butadiene, 2-) from IRIS .

    New toxicity values and metadata have been uploaded for cis-1,2-Dichloroethylene from IRIS .

    New toxicity values and metadata have been uploaded for Pentachlorophenol from IRIS .

    New toxicity values and metadata have been uploaded for 1,1,2,2-Tetrachloroethane from IRIS .

    New toxicity values and metadata have been uploaded for trans-1,2-Dichloroethylene from IRIS .

    New toxicity values and metadata have been uploaded for Hydrogen Cyanide and Cyanide Salts from IRIS .

    The RAGS Part A style toxicity profiles have been removed and replaced by a new tool that is updated automatically. The Chemical Data Profiles tool provides all the toxicity values and chemical specific parameters from every source available on the RAIS for the analyte selected. Additional chemical information such as ecological screening values and chemical metadata will be added over time.

    August 2010 Updates

    New toxicity values and metadata have been uploaded for 1,4-Dioxane from IRIS .

    The exposure time parameter was removed from the recreator exposure to incidental ingestion of soil/sediment for the PRG and risk tools.

    July 2010 Updates

    Several minor changes have recently been completed.

    We have consolidated all of our risk assessment guidance documents in one area and have created a document search tool.

    We have created a site map to help users get a quick feel how all our tools are organized.

    We have a new navigation change under our tools menu. We separated the toxicity values, metadata and parameter searches so that it is more transparent where each tool is located.

    The radionuclide decay chain tool has been updated

    The gamma radiation instrument response tool has a new user guide that provides more detail. Use this tool to calculate a detector reading to determine if your soil PRGs are being met during cleanup.

    March 2010 Updates

    IRIS has released a toxicological profile for Acrylamide. The chronic oral reference dose, chronic inhalation reference concentration, inhalation unit risk and oral slope factor have been updated as well as associated toxicity metadata.

    The RAIS has added acute and chronic Ecological Benchmarks from EPA Region 4 for saltwater.

    The RAIS has updated the ARAR Search Tool. Many of the footnotes are now visible.

    January 2010 Updates

    The RAIS has added toxicity values that are less than chronic. These include: subchronic, short-term and acute.

    The RAIS has updated chemical-specific parameters for beef and milk transfer coefficients and wet and dry plant uptake factors.

    Several new chemicals were added from California EPA sources.

    A Radionuclide Decay Chain Tool was added.

    October 2009 Updates

    The RAIS was given a new style. The user list is being verified. All databases are now running on ORACLE.

    The Paducah Background data was revised and new documents were added.

    The RAIS Main Tutorial has been updated.

    A discussion forum for all things related to risk assessment has been added.

    September 2009 Updates

    IRIS has released a toxicological profile for Thallium and its many salts. The chronic oral reference doses have been withdrawn. These values have been retained on the RAIS and given a reference of WITHDRAWN and a special footnote given to the values for useage instructions.

    IRIS has released a toxicological profile for 1,2,3-Trichloropropane. The chronic oral reference dose, chronic inhalation reference concentration and oral slope factor have been updated as well as associated toxicity metadata. 1,2,3-Trichloropropane is a mutagen.

    IRIS has released a toxicological profile for Bromobenzene. The chronic and subchronic oral reference doses and the chronic and subchronic inhalation reference concentrations have been updated as well as associated toxicity metadata.

    IRIS has released a toxicological profile for Cerium Oxide and Cerium Compounds. The chronic inhalation reference concentration has been updated as well as associated toxicity metadata.

    IRIS has released a toxicological profile for Chlordecone (kepone). The oral slope factor and the chronic oral reference dose have been updated as well as associated toxicity metadata.

    IRIS has released a toxicological profile for 2-Hexanone . The chronic inhalation reference concentration and the chronic oral reference dose have been updated as well as associated toxicity metadata.


    April 2009 Updates

    The half-life and lambda parameters were set to units of years. Toxicity Value Tool


    March 2009 Updates

    Densities were added to the Toxicity Value Tool .

    Melting points, boiling points, vapor pressures and water solubilities were added for many inorganics.


    February 2009 Updates

    The PRG tool was modified to generate tapwater noncarcinogenic PRGs based on adult exposure rather than child. Toxicity values, metadata and the RAGS Part A profile for Nitrobenzene were updated based on a new IRIS summary.

    The biota intakes rates in the PRG section were updated to more accurately reflect the intent of the guidance.

    A new risk modeling calculation tool for chemicals and radionuclides is now on the RAIS. This tool has new user guides and presents the chronic daily intake (CDI) equations and exposure parameters. Users should note that the new equations do not present dermal toxicity values but do present the gastrointestinal absorption factors used to modify oral values. Also note that inhalation RfDs are no longer used but are replaced with RfCs. For chemicals, inhalation slope factors are replaced with inhalation unit risks. A new feature of the risk tool is the ability to change the toxicity values that are used as well as calculate risk for a chemical that is not in our pick list. If you have any comments about these new features, please contact Fred Dolislager.


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    December 2008 Updates

    A new PRG calculation tool for chemicals and radionuclides is now on the RAIS, http://rais.ornl.gov/prg/rais_prg_document.shtml. This tool has a new user guide and presents the equations and exposure parameters. Users should note that the new equations do not present dermal toxicity values but do present the gastrointestinal absorption factors used to modify oral values. Also note that inhalation RfDs are no longer used but are replaced with RfCs. For chemicals, inhalation slope factors are replaced with inhalation unit risks. A new feature of the PRG tool is the ability to change the toxicity values that are used as well as calculate a PRG for a chemical that is not in our pick list. The PRG tool uses the toxicity values presented on a newly formatted Toxicity Value page http://rais.ornl.gov/tox/tox_values.shtml. ATSDR and California EPA values are now included in the hierarchy. Soon, a new Risk Models page will be released using the same exposure values as the new PRG equations. Also soon to be released is a new section of the Toxicity Profiles tool that will create a real-time "RAGS Part A" format profile based on current toxicity data and chemical-specific parameters. If you have any comments about these new features, please contact Fred Dolislager.

    The half-life of Am-242m was changed from 152 to 141 years.


    May 2008 Updates

    Chemical specific parameters updated for PCB 81, PCB 170, PCB 180, PCB 189, PCB 126, PCB 167, PCB 157, PCB 156, PCB 123 and PCB 114.

    Mercuric Sulfide GIABS updated to 0.07 based on RAGS Part E Exhibit 4-1. Also the oral RfD has been modified to 0.0003 mg/kg-day to reflect the intent of, SRC SF 01-016a/09-25-02 "Risk Assessment Issue Paper for: Evaluation of the Provisional RfD for Mercuric Sulfide (CASRN 1344-48-5), that states the IRIS value for mercuric chloride should be protective of mercuric sulfide. Footnotes and references have been updated.


    June 2007 Updates

    Federal ARARs Updated.

    Mercuric Sulfide GIABS updated to 0.07 based on RAGS Part E Exhibit 4-1. Also the oral RfD has been modified to 0.0003 mg/kg-day to reflect the intent of, SRC SF 01-016a/09-25-02 "Risk Assessment Issue Paper for: Evaluation of the Provisional RfD for Mercuric Sulfide (CASRN 1344-48-5), that states the IRIS value for mercuric chloride should be protective of mercuric sulfide. Footnotes and references have been updated.


    September 2006 Updates

    TN ARARs are updated.

    EPA Eco-SSLs are updated.


    May 2006 Updates

    The toxicity values for chloral and chloral hydrate were reported to be combined on the RAIS and they have been separated. Appropriate chemical-specific parameters have been applied and metadata updated.

    A footnote was added to p-Chlorobenzoic acid giving screening RfDs.

    It is now possible to download references in the tab delimited files.

    The Federal ARARs were updated. Saltwater and organoleptic values were added.


    April 2006 Updates

    The RAIS is now using oral slope factors for radionuclides that have been calculated for adults only. These slope factors will be used for the indoor and outdoor worker scenarios as well as the construction/excavator scenarios.

    Oral reference doses were added for 4-Amino-2,6-Dinitrotoluene and 2-Amino-4,6-Dinitrotoluene. The toxicity values were taken from the EPA Region 9 PRG table as listed under the contaminant Aminodinitrotoluene with a reference of NCEA. Chemical-specific parameters were also updated.


    February 2006 Updates

    A new IRIS report for Phosgene CAS 75-44-5 has been released. A new chronic inhalation RfC has been released. Toxicity metadata have been updated. Chemical-specific parameters have been added.


    January 2006 Updates

    A new IRIS report for n-Hexane CAS 110-54-3 has been released. A new chronic inhalation RfC has been released. Toxicity metadata have been updated.

    The RAIS has adopted the California EPA slope factors for Tetrachloroethylene. The oral paper can be found here and the inhalation paper can be found here.


    September 2005 Updates

    A new IRIS report for Toluene CAS 108-88-3 has been released. A new chronic oral RfD and inhalation RfC have been released. Toxicity metadata have been updated.

    Oral toxicity values were added for Ethyl chloride from NCEA as reported in the US EPA Region 9 PRG table.

    Slope Factor values were added for Methyl tertbutyl ether (MTBE) from California EPA as reported in the US EPA Region 9 PRG table.

    An oral chronic RfD was added for 4-Nitrophenol from NCEA as reported in the US EPA Region 6 PRG table.

    Vapor pressures were added for 9 Organics.


    August 2005 Updates

    Chemical-specific parameters were updated for all inorganic compounds that formerly referenced the EPI software suite. Initiated by user feedback, it was discovered that the software was not generally suitable for inorganic compound estimation and EPI's underlying experimental database was very limited. This oversight on our part can unfortunately be found in many EPA products such as SCDM, WATER8, CHEM9, etc. The parameters that were updated include: boiling point, melting point, vapor pressure, unitless Henry's Law constant, fish BCF, Koc (not applicable for inorganics), logKow, water solubility and permeability constant. Boiling point, melting point and vapor pressure were not used in any PRG or risk equations, however, the other parameters were and new calculations may be different from your previous results. A very concerted effort was made to compile a complete and defensible database. Please contact Fred Dolislager with any questions.


    July 2005 Updates

    An Oral RfD was added for Barium from IRIS. A Dermal RfD was also calculated. Metadata was updated.


    June 2005 Updates

    An Oral RfD was added for Iron from the EPA Regional tables. A Dermal RfD was also calculated.


    May 2005 Updates

    The RAIS Team has allowed the newly programmed risk and PRG calculators to retain the ability to calculate dermal risk from soil contact for the indoor industrial exposure route. However we have set the default surface area to be 0. This effectively removes the route from the equation to be compliant with Superfund. Should a user desire to include the dermal route, a surface area may be entered by using the "prompt for parameters" option.


    March 2005 Updates

    The RAIS Team has completed a total upgrade to the risk modeling calculator tool. There are new equations and new exposure parameters that reflect recent EPA guidance. After hours of diligent programming, we believe that all the bugs have been corrected. Please take the time to reread the "notes" sections where they occur. They contain many important clues to make the risk calculation process transparent. Please observe the many links that are now present in the output and the "prompt for parameters" page. When risks are returned, you can click on the column headers and you will be taken to the equation parameters page. When selecting variables in the "prompt for parameters" page you can click on the equations and be taken to the equation parameters page. The selected parameters are then returned with the risk results. What you can't "see" while using the new risk tool is that ALL the programs that make the RAIS risk calculator work are brand new. Leslie Galloway has diligently designed and structured the code in a way that makes the results visually pleasing as well as seamlessly functional. Future updates will be much simpler. With that in mind, please take the time to test and investigate all the new changes and tell us what you think. When doing multiple chemicals, the RAIS now sums the risks for you and highlights COCs. The risk totals even take into account the one-hit rule.

    A new IRIS oral reference dose of 7E-04 was released for Perchlorate and Perchlorate Salts (CAS 7790-98-9). The salts include Ammonium perchlorate (CAS 7790-98-9), Lithium perchlorate (CAS 7791-03-9), Potassium perchlorate (CAS 7778-74-7) and Sodium perchlorate (CAS 7601-89-0). Metadata and chemical-specific data have also been updated.


    February 2005 Updates

    A newly updated ecological screening benchmark database was loaded into the RAIS. This is the same database currently in SADA ver 4.


    November 2004 Updates

    The RAIS Team has completed a total upgrade to the PRG calculator tool. There are new equations and new exposure parameters that reflect recent EPA guidance. After hours of diligent programming, we believe that all the bugs have been corrected. Please take the time to reread the "notes" sections where they occur. They contain many important clues to make the PRG calculation process transparent.

    Please observe the many links that are now present in the output and the "prompt for parameters" page. When PRGs are returned, you can click on the column headers and you will be taken to the equation parameters page. When selecting variables in the "prompt for parameters" page you can click on the equations and be taken to the equation parameters page. The selected parameters are then returned with the PRG results.

    What you can't "see" while using the new PRG tool is that ALL the programs that make the RAIS PRGs work are brand new. Leslie Galloway has diligently designed and structured the code in a way that makes the results visually pleasing as well as seamlessly functional. Future updates will be much simpler. With that in mind, please take the time to test and investigate all the new changes and tell us what you think. Similar changes will soon be made to the forward risk calculator tool.


    October 2004 Updates

    The RAIS has updated the subchronic oral RfD for arsenic. The previous value (5.0E-03) was withdrawn. The new value of 3.0E-04 comes from HEAST which has taken the chronic value from IRIS.


    September 2004 Updates

    The RAIS ABS values have been updated for those analytes found in "Risk Assessment Guidance for Superfund (RAGS), Volume I: Human Health Evaluation Manual (Part E, Supplemental Guidance for Dermal Risk Assessment) Final July 2004" Exhibit 3-4.


    August 2004 Updates

    The RAIS has been updated and a toolbar has been added to the top of every page for user convenience. If you have any comments or requests please contact Fred Dolislager.

    The toxicity summary for Boron and Compounds has been revised, and a Toxicological Review for Boron and Compounds has been added to the IRIS Web site. The following toxicity values are to be used for Boron and Compounds:

    • The Chronic Oral Reference Dose is now 2.0E-01 (mg/kg-day) and associated metadata have been updated.
    • The Dermal Reference Dose of 1.8E-01 (mg/kg-day) was calculated from the oral RfD.


    July 2004 Updates

    The toxicity summary for 1,2-Dibromoethane has been revised, and a Toxicological Review for 1,2-Dibromoethane has been added to the IRIS Web site. The following toxicity values are to be used for 1,2-Dibromoethane:

    • The new Chronic Inhalation Reference Concentration (RfC) of 9.0E-03 (mg/m3) has been added. The associated toxicity metadata have also been updated.
    • The Chronic Inhalation Reference Dose of 2.57E-03 (mg/kg-day) was calculated from the RfC.
    • The Chronic Oral Reference Dose is now 9.0E-03 (mg/kg-day) and associated metadata have been updated.
    • The Dermal Reference Dose of 7.2E-03 (mg/kg-day) was calculated from the oral RfD.
    • The Oral Slope Factor is now 2.00E+00 (mg/kg-day)-1 and associated metadata has been added.
    • The Dermal Slope Factor is now 2.50E+00 (mg/kg-day)-1 and was calculated from the oral slope factor.
    • The Oral Unit Risk is now 6.00E-02 (mg/L)-1 and associated metadata has been added.
    • The Inhalation Unit risk is now 6.0E-01 (mg/m3)-1 associated metadata has been added.
    • The Inhalation Slope Factor is now 2.10E-01 (mg/kg-day)-1 and was calculated from the inhalation unit risk.


    May 2004 Updates

    Slope Factors (inhalation, ingestion-diet and ingestion-tapwater) were added for Cm-248 and Cf-252. These are spontaneous fission isotopes and their slope factors have not yet been published in HEAST or FGR 13. These new values were obtained from the ORNL team that created FGR 13.

    ARARs are now available on-line for Wisconsin and New York.


    December 2003 Updates

    The Oral Subchronic Reference Dose for Chromium III was changed from 1.0E+00 to 1.5E+00 mg/kg-d . According to HEAST, the chronic value was adopted as the subchronic value. The chronic value is listed on IRIS as 1.5E+00 mg/kg-d. The previous subchronic oral RfD of 1.0E+00 was an artifact of the original HEAST database. The associated dermal subchronic value is also updated.


    September 2003 Updates

    The toxicity summary for Methyl ethyl ketone (MEK) has been revised, and a Toxicological Review for MEK has been added to the IRIS Web site. The following toxicity values are to be used for MEK:

    • The Chronic Inhalation Reference Concentration (RfC) is now 5.00E+00 mg/m3) based on the critical effect of developmental toxicity (skeletal variations).
    • The associated toxicity metadata have also been updated.
    • The Chronic Inhalation Reference Dose is now 1.43E+00 (mg/kg-day).

    The toxicity summary for Cyclohexane has been revised, and a new Toxicological Review for Cyclohexane has been added to the IRIS Web site. The following toxicity values are to be used for Cyclohexane:

    • The Chronic Inhalation Reference Concentration is now 6.00E+00 (mg/m3) based on the critical effect of reduced pup weights in the F1 and F2 generations.
    • The Chronic Inhalation Reference Dose of 1.71E+00 (mg/kg-day) was calculated from the RfC.
    • The associated toxicity metadata have also been updated.

    The toxicity summary for Dichloroacetic acid has been revised, and a Toxicological Review for Dichloroacetic acid has been added to the IRIS Web site. The following toxicity values are to be used for Dichloroacetic acid:

    • The Chronic Oral Reference Dose (RfD) is now 4.00E-03 mg/kg-day) based on the critical effect of lesions observed in the testes, cerebrum, cerebellum, and liver.
    • The associated toxicity metadata have also been updated.
    • The Dermal Reference Dose is now 2.00E-03 (mg/kg-day).
    • The drinking water unit risk of 1.4E-03 (mg/L)-1was added based on hepatoadenoma and hepatocarcinoma in mice.
    • The oral slope factor of 5.00E-02 (mg/kg-day)-1was added based on hepatoadenoma and hepatocarcinoma in mice.
    • The associated toxicity metadata have also been updated.
    • The Dermal Slope Factor is now 1.00E-01 (mg/kg-day)-1.


    August 2003 Updates

    The toxicity summary for Acetone has been revised, and a new Toxicological Review for Acetone has been added to the IRIS Web site. The following toxicity values are to be used for Acetone:

    • The Chronic Oral Reference Dose is now 9.0E-01 (mg/kg-day) based on the critical effect of nephropathy.
    • The Dermal Reference Dose is now 7.47E-01 (mg/kg-day).
    • The associated toxicity metadata have also been updated.

    The toxicity summary for Hydrogen sulfide has been revised, and a Toxicological Review for Hydrogen sulfide has been added to the IRIS Web site. The following toxicity values are to be used for Hydrogen sulfide:

    • The Chronic Inhalation Reference Concentration (RfC) is now 2.0E-03 (mg/m3) based on the critical effect of nasal lesions of the olfactory mucosa.
    • The associated toxicity metadata have also been updated.
    • The Chronic Oral Reference Dose of 3.0E-03 (mg/kg-day) was withdrawn. This value remains on the RAIS and has been footnoted. When a new value is available from IRIS, it will replace the withdrawn value.


    July 2003 Updates

    The Ethylbenzene cancer toxicity values have been withdrawn by NCEA. This chemical is now being reassessed for IRIS which automatically flags further use of any provisional cancer or non-cancer assessments. However, the RAIS has retained these values and added appropriate footnotes.

    Toxicity values have been added for Copper. HEAST presents a drinking water standard of 1.3 mg/L for Copper. The RAIS has converted this value into a chronic and subchronic RfD for oral and dermal exposure. The following toxicity values are to be used for Copper:

    • The Chronic Oral Reference Dose (RfD) of 4.00E-02 (mg/kg-day) was added.
    • The Subchronic Oral Reference Dose (RfD) of 4.00E-02 (mg/kg-day) was added.
    • The Chronic Dermal Reference Dose (RfD) of 1.20E-02 (mg/kg-day) was added.
    • The Subchronic Dermal Reference Dose (RfD) of 1.20E-02 (mg/kg-day) was added.


    June 2003 Updates

    The toxicity summary for Acrolein has been revised, and a new Toxicological Review for Acrolein has been added to the IRIS Web site. The following toxicity values are to be used for Acrolein:

    • The Chronic Inhalation Reference Concentration (RfC) of 2.0E-05 (mg/m3) has not changed but the associated toxicity metadata has been updated.
    • The Chronic Oral Reference Dose is now 5.0E-04 (mg/kg-day) based on critical effects of decreased survival.
    • The Dermal Reference Dose is now 4.0E-04 (mg/kg-day).

    The toxicity summary for Methyl isobutyl ketone (MIBK) has been revised, and a Toxicological Review for MIBK has been added to the IRIS Web site. The following toxicity values are to be used for MIBK:

    • The Chronic Inhalation Reference Concentration (RfC) of 3.0E+00 (mg/m3) has been added. The associated toxicity metadata have also been added as follows: critical effects of reduced fetal body weight.
    • The Chronic Inhalation Reference Dose of 8.57E-01 (mg/kg-day) was calculated from the RfC.


    May 2003 Updates

    The toxicity summary for Trichloroethylene (TCE) has been revised, and a new Metadata Report for TCE has been added to the EIMS Web site. The following toxicity values are to be used for TCE:

    • The Chronic Inhalation Reference Concentration (RfC) of 4.0E-02 (mg/m3) has been added. The associated toxicity metadata have also been added as follows: critical effects in the central nervous system, liver, and endocrine system.
    • The Chronic Inhalation Reference Dose of 1.14E-02 (mg/kg-day) was calculated from the RfC.
    • The Chronic Oral Reference Dose is now 3.0E-04 (mg/kg-day) based on critical effects in the liver, kidney, and developing fetus.
    • The Dermal Reference Dose is now 4.5E-05 (mg/kg-day).
    • The Oral Slope Factor is now 4.00E-01 (mg/kg-day)-1. No metadata is presented in the report.
    • The Inhalation Slope Factor is now 4.00E-01 (mg/kg-day)-1. No metadata is presented in the report.
    • The Dermal Slope Factor is now 2.67E+00 (mg/kg-day)-1.


    April 2003 Updates

    The toxicity summary for Benzene has been revised, and a new Toxicological Review for Benzene has been added to the IRIS Web site. The following changes have been made on the toxicity databases and toxicity profiles:

    • The Chronic Inhalation Reference Concentration (RfC) of 3.0E-02 (mg/m3) has been added. The associated toxicity metadata have also been added as follows: UF = 300; MF = 1; critical effect = decreased lymphocyte count; inhalation study confidence= medium; study reference = Rothman et. al., 1996; species = human; basis = BMCL.
    • The Chronic Inhalation Reference Dose of 8.57E-03 (mg/kg-day) was calculated from the RfC.
    • The Chronic Oral Reference Dose of 4.0E-03 (mg/kg-day) has been added. The associated toxicity metadata have also been added as follows: UF = 300; MF = 1; critical effect = decreased lymphocyte count; inhalation study confidence= medium; study reference = Rothman et. al., 1996; species = human; basis = BMCL.
    • The Chronic Dermal Reference Dose of 3.88E-03 (mg/kg-day) was calculated from the Chronic Oral RfD.


    March 2003 Updates

    The toxicity summary for Xylenes has been revised, and a new Toxicological Review for Xylenes has been added to the IRIS Web site. The following changes have been made on the toxicity database:

    • The Chronic Inhalation Reference Concentration (RfC) of 1.0E-01 (mg/m3) has been added. The associated toxicity metadata have also been added as follows: UF = 300; MF = 1; critical effect = impaired motor coordination (decreased rotarod performance); inhalation study confidence= medium; study reference = Korsak et. al., 1994; species = male rats; basis = NOAEL (HEC).
    • The Chronic Inhalation Reference Dose of 2.86E-02 (mg/kg-day) was calculated from the RfC.
    • The Chronic Oral Reference Dose is now 2.0E-01 (mg/kg-day).
    • The Dermal Reference Dose is now 1.84E-01 (mg/kg-day).

    Diesel engine exhaust was added as a new Chemical on the IRIS website. The following additions have been made:

    • The Chronic Inhalation Reference Concentration (RfC) of 5.0E-03 (mg/m3) was added. The associated toxicity metadata have also been updated as follows: UF = 30; MF = 1; critical effect = pulmonary inflammation and histopathology; inhalation study confidence = medium; study reference = Ishinishi 1988; species = rat; basis = NOAEL (HEC).
    • The Chronic Inhalation Reference Dose (RfD) of 1.43E-03 (mg/kg-day) was calculated from the RfC.


    November 2002 Updates

    The summary for 1,3-Butadiene has been revised, and a new Toxicological Review for 1,3-Butadiene has been added to the IRIS Web site. The following changes have been made on the toxicity database:

    • The Chronic Inhalation Reference Concentration (RfC) of 2E-03 (mg/m3) has been added. The associated toxicity metadata have also been added as follows: UF = 1000; MF = 1; critical effect = ovarian atrophy; confidence = medium; study reference = NTP 1993; species = mouse; target organ = ovaries; basis = BMCL.
    • The Inhalation Unit Risk is now 3.0E-02 (mg/m3)-1. The associated toxicity metadata have also been added as follows: inhalation study reference = US EPA 2002 and Health Canada 1998; study species = human; target organ = lymphatic and hematopoietic tissue; tumor = leukemia.
    • The Inhalation slope factor is now 1.05E-01(mg/kg-day)-1.
    • The EPA Cancer Classification was changed from B2, probable human carcinogen to "carcinogenic to humans by inhalation".

    The summary for Phenol has been revised, and a new Toxicological Review for Phenol has been added to the IRIS Web site. The following changes have been made on the toxicity database:

    • The Chronic Oral Reference Dose (RfD) of 6.0E-01 (mg/kg-day) was changed to 3.0E-01 (mg/kg-day). The associated toxicity metadata have also been updated as follows: UF = 300; MF = 1; critical effect = decreased maternal weight gain; confidence = medium/high; study reference = Argus Research Laboratories 1997; species = rat; target organ = none; basis = BMDL.
    • The Chronic Dermal Reference Dose (RfD) of 5.4E-01 (mg/kg-day) was changed to 2.7E-01 (mg/kg-day).

    The inhalation unit risk value for asbestos was changed on the RAIS to be 2.3E-04 (fiber/L)-1. Also the inhalation slope factor was changed to 8.05E-07 (fiber/kg-day)-1. These changes are a result of converting the IRIS units to RAIS standard units.


    October 2002 Updates

    The Chemical-specific Parameters database was updated for nearly all chemicals for their references and/or values. The references were updated to provide complete definition of the source or the process used to derive the values. In the process of updating these references, it was discovered that WATER8 was no longer supplied by the US EPA. WATER8 was a common reference for many parameters. The RAIS now uses values taken from EPA's EPI software for the following parameters: molecular weight, log octanol-water partition coefficient (log Kow or log p), dermal permeability constant (Kp), organic carbon partition coefficient (Koc), water solubility (S), fish bioconcentration factor, and Henry law constant (H').

    The ARARs have been updated for: Federal, Tennessee, South Carolina, Kentucky, Ohio, Washington, and Illinois. Many contaminants were added such as fecal coliform, giardia lamblia, viruses, etc. These additions were common among all States.

    1,1-Dichlorethylene tox values were updated based on a new IRIS toxicological release at http://www.epa.gov/IRIS/toxreviews/0039-tr.pdf. The non-cancer Reference Dose (RfD) was changed from 0.009 mg/kg-day to 0.05 mg/kg-day.

    The excel spread sheets were also updated that contain the toxicity values.


    June 2002 Updates

    Estimation of Whole-Fish Contaminant Concentrations from Fish Fillet Data (ES/ER/TM-202) has been added to the Risk Assessment Guidance pages in pdf format.


    May 2002 Updates

    There are new Inhalation Unit Risk (URi) values on the RAIS for 2,3,7,8-TCDD and associated chemicals based on adjustment with a Toxicity Equivalent Factor (TEF). This change was necessary to correct an error in the standard unit conversions from HEAST format to RAIS format. The standard units for inhalation unit risk in HEAST are (ug/m3)-1, however the HEAST URi for 2,3,7,8-TCDD was presented in the nonstandard units of (pg/m3)-1. Below are the new toxicity values for URi, presented in (mg/m3)-1 for the RAIS:

    • 2,3,7,8-TCDD, TEF=1.0; new URi = 3.30E+04
    • 2,3,7,8-PeCDD, TEF=0.5; new URi = 1.65E+04
    • 2,3,7,8-HxCdd, TEF=0.1; new URi = 3.30E+03
    • 2,3,7,8-HpCdd, TEF=0.01; new URi = 3.30E+02
    • OCDD, TEF=0.001; new URi = 3.30E+01
    • 2,3,7,8-TCDF, TEF=0.1; new URi = 3.30E+03
    • 1,2,3,7,8-PeCDF, TEF=0.5; new URi = 1.65E+04
    • 2,3,4,7,8-PeCDF, TEF=0.05; new URi = 1.65E+03
    • 2,3,7,8-HxCDF, TEF=0.1; new URi = 3.30E+03
    • 2,3,7,8-HpCDF, TEF=0.01; new URi = 3.30E+02
    • OCDF, TEF=0.001. new URi = 3.30E+01


    October 2001 Updates

    The summary for Quinoline has been revised, and a new Toxicological Review for Quinoline has been added to the IRIS Web site. The following changes have been made on the toxicity database:

    • The Oral Slope Factor is now 3.0 (mg/kg-day)-1.
    • The Dermal Slope Factor is now 6.0 (mg/kg-day)-1.
    • The Oral Unit Risk is now 9.0E-02 (mg/L)-1.
    • The EPA Cancer Classification is now B2, probable human carcinogen.


    September 2001 Updates

    A new, searchable database of chemical-specific toxicity metadata contains values needed in human health toxicity assessments. This information can be used to help complete EPA RAGs Part D tables and supplement toxicity assessments. The database is accessible at http://rais.ornl.gov/tox/metadata.shtml.

    RAGS Part A format toxicity profiles were added for the 64 chemicals currently on the RAIS. This format follows the requirements from RAGS Part A, are maintained with current toxicity information, and are designed for inclusion in the main body of a risk assessment. These new profiles may be found at the following page: http://rais.ornl.gov/tox/rap_toxp.shtml.


    July 2001 Updates

    The summary for Chloromethane has been revised, and a new Toxicological Review for Chloromethane has been added to the IRIS Web site. The following changes have been made on the toxicity database:

    • Inhalation Chronic RfC = 9.0E-02 (mg/kg-day)
    • Inhalation Chronic RfD = 2.57E-02 (mg/kg-day)
    • EPA Weight of Evidence Class = D

    The summary for Hexachlorocyclopentadiene (HCCPD) has been revised, and a new Toxicological Review for Hexachlorocyclopentadiene (HCCPD) has been added to the IRIS Web site. The following changes have been made on the toxicity database:

    • Oral Chronic RfD = 6.0E-03 (mg/kg-day)
    • Dermal Chronic RfD = 3.0E-03 (mg/kg-day)
    • Inhalation Chronic RfC = 2.0E-04 (mg/kg-day)
    • Inhalation Chronic RfD = 5.7E-05 (mg/kg-day)
    • EPA Weight of Evidence Class = E


    June 2001 Updates

    Bromate (CAS 15541-45-4) has been added to IRIS. Therefore, the toxicity database has been updated with the following information:

    • Oral Chronic RfD = 4.0E-03 (mg/kg-day)
    • Dermal Chronic RfD = 8.0E-04 (mg/kg-day)
    • Oral Slope Factor = 7.0E-01 (mg/kd-day)-1
    • Oral Unit Risk = 2.0E-02 (mg/L)-1
    • Dermal Slope Factor = 3.5E+00 (mg/kd-day)-1
    • GI Absorption Factor = 0.2
    • Dermal Absorption Factor = 0.001
    • EPA Cancer Class = B2


    May 2001 Updates

    Water Solubility (S) was added to the chemical-specific parameters search feature.

    Addresses and phone numbers were updated on the contacts pages.

    For 47 chemicals, the inhalation slope factor was changed from a HEAST value to a conversion from the IRIS unit risk value, which is more current. A footnote was also added to indicate this conversion. This change occurred for the following chemicals: Acrylamide; Acrylonitrile; Aldrin; Aramite; Azobenzene; Benzene; Beryllium; Bis(2-chloroethyl)ether; Bis(chloromethyl)ether; Bromoform; Butadiene, 1,3-; Carbon Tetrachloride; Chlordane; Chloroform; Chromium VI (chromic acid mists and particulates); Coke Oven Emissions; DDT; Dibromoethane, 1,2-; Dichloroethylene, 1,1-; Dichloropropene, 1,3-; Dieldrin; Diphenylhydrazine, 1,2-; Epichlorohydrin; Formaldehyde; Heptachlor; Heptachlor Epoxide; Hexachlorobenzene; Hexachlorobutadiene; Hexachlorocyclohexane, Alpha-; Hexachlorocyclohexane, Beta-; Hexachlorocyclohexane, Technical; Hexachloroethane; Hydrazine; Hydrazine Sulfate; Nickel Refinery Dust; Nickel Subsulfide; Nitrosodiethylamine, N-; Nitrosodimethylamine, N-; Nitroso-di-N-butylamine, N-; Nitrosopyrrolidine, N-; Propylene Oxide; Tetrachloroethane, 1,1,2,2-; Toxaphene; Trichloroethane, 1,1,2; Trichlorophenol, 2,4,6; and Vinyl Chloride.


    February 2001 Updates

    Updated the Oral RfD for Uranium (Soluble Salts). The new value is 6.0E-4 mg/kg/day and the new Dermal RfD is 5.1E-4 mg/kg/day. Source: Federal Register, (very large file) Thursday December 7, 2000. Part II, Environmental Protection Agency. 40 CFR Parts 9, 141, and 142 - National Primary Drinking Water Regulations; Radionuclides; Final Rule. p 76713. [PDF] Also see Soil Screening Guidance for Radionuclides: User's Guide pg 1-6.

    Updated files for the Federal Regulatory Standards. The following is a list of the changes/additions:

    • Deletion of the Chloroform MCLG
    • Revision of the Arsenic MCL and MCLG
    • Deletion of proposed MCLS: all other manmade radionuclides, gross alpha, gross beta, natural uranium, radium 226, radium 228, strontium 90, and tritium (Note: the existing MCL for combined radium 226/228, gross alpha,gross beta, and photon radioactivity were retained by the rule making).
    • Addition of the proposed radon 222 MCL
    • Addition of the natural uranium MCL
    • Addition of the methyl mercury water quality criteria for human health (expressed as fish tissue)
    • Addition of the water quality criteria for nutrients
    • Addition of the water quality criteria for the non-priority pollutants (45 substances)
    • Corresponding changes/additions were also made in the appropriate footnotes.


    January 2001 Updates

    Note to Users: There has been a new release of toxicity values for radionuclides as presented in Federal Guidance Report No. 13. Essentially, every slope factor has changed. In addition, oral values are tabulated separately for ingestion of tap water, dietary intakes (food), and incidental soil ingestion. Please consult the User's Guide section on radionuclide carcinogenicity for the derivation of radionuclide slope factors and guidance on their use. Also please note that the output of the Preliminary Remediation Goal and Human Health Exposure Modeling sections will reflect these changes in toxicity values.

    Added a link to the Tools page for EPA's Soil Screening Guidance for Radionuclides.


    October 2000 Updates

    Chloral toxicity has been updated on IRIS. The chemical name is now "Chloral Hydrate" and the new Oral Chronic RfD is 1E-1.

    Chlorine Dioxide toxicity has been updated on IRIS. The new Oral Chronic RfD is 3E-2.

    Chlorite (Sodium Salt) toxicity has been updated on IRIS. The new Oral Chronic RfD is 3E-2.

    Four missing references were added to the Beryllium formal toxicity profile.


    September 2000 Updates

    A new link to "Risk Assessment Guidance for Superfund Volume 3 Part A Process for Conducting Probabilistic Risk Assessment" (RAGS 3A) has been added to the Regulatory Guidance page.

    A new link to "Region IV Supplemental Guidance to Risk Assessment Guidance for Superfund" has been added to the Regulatory Guidance page.

    A sentence was added to the end of all toxicity value footnotes for Mercury compounds (Inorganic Mercury, Elemental Mercury, Mercuric Chloride, and Mercuric Sulfide) in order to ensure proper use of the toxicity value by referring the user to toxicity information regarding other forms of Mercury.


    August 2000 Updates

    The IRIS summary for Vinyl Chloride has been revised, and a new Toxicological Review for Vinyl Chloride has been added to the IRIS Web site. The following changes to Vinyl Chloride have been made on the RAIS:

    • The oral RfD is now 3E-3 mg/kg/day.
    • The dermal RfD has been added to reflect the addition of the oral RfD.
    • The inhalation RfC is now 1E-1 mg/m3.
    • The inhalation RfD had been added to reflect the addition of the inhalation RfC.
    • The oral slope factor has been changed to 1.4 (mg/kg/day)-1.
    • The dermal slope factor has been changed to reflect the change in the oral slope factor.
    • The oral unit risk has been changed to 4.2E-2 (mg/L)-1.
    • The inhalation unit risk has been changed to 8.8E-3 (mg/m3)-1.
    • The inhalation slope factor has been changed to reflect the change in the inhalation unit risk.

    New ecological guidance for Region IV, "Amended Guidance on Ecological Risk Assessment at Military Bases: Process Considerations, Timing of Activities, and Inclusion of Stakeholders", has been added to the Regulatory Guidance page.

    "Improved Methods for Calculating Concentrations Used in Exposure Assessments", BJC/OR-416, has replaced the draft TM, ES/ER/TM-211, on the Risk Assessment Guidance page.


    June 2000 Updates

    Kentucky, Illinois, and South Carolina state regulations have been updated.

    The IRIS summary for 1,3-Dichloropropene has been revised, and a new Toxicological Review for 1,3-Dichloropropene has been added to the IRIS Web site. The following changes to 1,3-Dichloropropene have been made on the RAIS:

    • The oral RfD has been changed to 3E-2 mg/kg/day.
    • The dermal RfD has been changed to reflect the change in the oral RfD.
    • The oral slope factor has been changed to 1E-1 (mg/kg/day)-1.
    • The dermal slope factor has been changed to reflect the change in the oral slope factor.
    • The oral unit risk has been changed to 3E-3 (mg/L)-1.
    • The inhalation unit risk has been changed to 4E-3 (mg/m3)-1.
    • The inhalation slope factor has been changed to reflect the change in the inhalation unit risk.


    April 2000 Updates

    The following chemicals have been added to the RAIS with provisional toxicity values - CAS numbers are in parentheses:

    • Dibenzofuran (000132-64-9)
    • Dichlorobenzophenone, 4,4'- (000090-98-2)
    • Methyl Mercaptan (000074-93-1)
    • Thiocyanate (000463-56-9)
    • Trimethylbenzene, 1,2,4- (000095-63-6)
    • Trimethylbenzene, 1,3,5- (000108-67-8)

    Please check the toxicity database for chemical-specific provisional toxicity values and other physical properties.

    The following chemicals have new provisional toxicity values:

    • Antimony
      • Subchronic RfC=4E-4
      • Subchronic RfD=2E-4
    • Cadmium
      • Subchronic RfC=9E-4
    • Carbon Tetrachloride
      • Subchronic RfC=2E-2
    • Chlorine
      • Chronic RfC=2E-4
    • Dimethyl Hydrazine, 1,1-
      • Inhalation UR=4.9E0
      • Oral SF=3E0
    • Ethylbenzene
      • Inhalation UR=1.1E-3
      • Subchronic RfC=1E0
      • Subchronic RfD=1.1E-1
    • Hexachlorobenzene
      • Subchronic RfD=1E-4
    • Methyl Hydrazine
      • Inhalation UR=4.9E0
      • Oral SF=3E0
    • Toluene
      • Subchronic RfC=9.23E-1
    • Trichloroethane, 1,1,1-
      • Chronic RfC=2.2E0
      • Subchronic RfC=2.2E+1

    Please check the toxicity database for other chemical-specific toxicity values for these chemicals.

    The Paducah background values have been updated. See the background database for further information.


    February 2000 Updates

    The IRIS summary for benzene has been revised with a new oral carcinogenicity assessment. The oral unit risk is now 1.6E-3 (mg/L)-1 and the oral slope factor is now 5.5E-2 (mg/kg/day)-1.

    Footnote "h" of Toxicity Footnotes has been revised to read "Value expressed as fibers/L".

    The following chemicals have been assigned CAS numbers:

    • Polybrominated Biphenyls -- 059536-65-1
    • Benzene, Ethylmethyl -- 025550-14-5
    • Benzene, Methylpropenyl -- 000768-00-3

    The inhalation slope factor for Diethylstilbesterol was withdrawn from HEAST and is now referenced with a 'w'. The withdrawn date is July 1997.

    The oral reference dose for Methyl Methacrylate is now referenced as coming from IRIS.


    January 2000 Updates

    Incorrect Exposure Frequency (EF) units for the PRG search table output were corrected to now read "day/year".

    A reference for RAGS Part B, Appendix D was added to the PRG and Human Health Risk Exposure Modeling pages.

    Numerous missing/incorrect links were updated throughout the site, especially on the EPA Human Health Related Guidance page.


    December 1999 Updates

    New IRIS Summary and Toxicological Review for Ethylene glycol monobutyl ether (EGBE) have been added to the IRIS web site. The oral chronic reference dose is 5E-1 mg/kg/day, the dermal chronic reference dose is 2.5E-1 mg/kg/day, the inhalation chronic reference concentration is 1.3E+1 mg/m3, and the inhalation chronic reference dose is 3.71E+0 mg/kg/day. There were no supporting data for carcinogenicity at this time.

    Tennessee and Ohio State Guidelines were updated to reflect recent changes.


    October 1999 Updates

    The ORO Risk Assessment Guidance pages were updated to remove three inactive procedures: "Verifying Calculations in Human Health and Ecological Risk Assessments", EM&EF/ER-P2009; "Requirements for Conducting Human Health and Ecological Risk Assessments", EM&EF/ER- S2010; and "Integrating Contractor Issues in Risk Assessment", ER/C-S2002.

    One new procedure was added to the ORO Risk Assessment Guidance pages: "Environmental Management: Human Health and Ecological Risk Assessment", ES-A-2100.


    September 1999 Updates

    Additional text and links were added to the boxes in the Risk Assessment Overview Diagram.


    August 1999 Updates

    Description of the configuration control process was added to the top of the "Tools" page.


    July 1999 Updates

    Incorrect text was removed from Section 2.3 "Derivation of Dermal Toxicity Values" of "Using Toxicity Values in Risk Assessment", which is part of the "Toxicity Values" Tool page.

    The html version of "Guidance for Conducting Risk Assessments and Related Risk Activities for the DOE-ORO Environmental Management Program", BJC/OR-271, is available on the Technical Memoranda lists from the "ORO Risk Assessment Guidance" page, and all human health strategy document links have been re-linked to this file.

    Established Regulatory Limits for Surface Water and Groundwater for Illinois, South Carolina, and Washington and revised federal limits were added to the Federal and State Guidelines.


    June 1999 Updates

    The inhalation RfC for Beryllium and compounds has been changed from 2e-2 ug/m^3 to 2e-5 mg/m^3 and the inhalation RfD for Beryllium and compounds has been changed from 5.71e-3 ug/kg/day to 5.71e-6 mg/kg/day.

    Html code that appears in the tab/comma delimited version of the PRG output has been removed.


    May 1999 Updates

    The human health strategy document "Risk Assessment Strategy at DOE-ORO," ES/ER/TM-180 has been superceded by the following document: Guidance for Conducting Risk Assessments and Related Risk Activities for the DOE-ORO Environmental Management Program, BJC/OR-271.

    Pdf files for the following technical memoranda were added to "ORO Risk Assessment Guidance":

    • ES/ER/TM35/R1, An Introductory Guide to Uncertainty Analysis in Environmental and Health Risk Assessment;
    • ES/ER/TM-38, Approach and Strategy for Developing Human Health Toxicity Information for Contaminants of Concern at Sites Administered by the U.S. Department of Energy Oak Ridge Field Office Environmental Restoration Program;
    • ES/ER/TM112/R2, Environmental Restoration Risk-Based Prioritization Work Package Planning and Risk Ranking Methodology, June 1995 Revision;
    • ES/ER/TM-131, Radiological Criteria for Remedial Actions at Radioactively Contaminated Sites; ES/ER/TM-134, Decision Support for CERCLA Investigations: An Introduction to Decision Analysis Applications;
    • ES/ER/TM-187, Criteria for Establishing De Minimis Levels of Radionuclides and Hazardous Chemicals in the Environment;
    • ES/ER/TM-212, Relative Risk Ranking Evaluation for DOE Oak Ridge Operations;
    • BJC/OR-80, Radiological Benchmarks for Screening Contaminants of Potential Concern for Effects on Aquatic Biota;
    • BJC/OR-112, Biota-Sediment Accumulation Factors for Invertebrates: Review and Recommendations for the Oak Ridge Reservation;
    • BJC/OR-1333, Empirical Models for the Uptake of Inorganic Chemicals from Soil by Plants


    April 1999 Updates

    The Established Regulatory Limits for Surface Water and Groundwater have been revised for Tennessee and Kentucky.

    Rad CAS numbers were revised to enable selection of rads with "m" or "+d" on the human health risk models tool.


    March 1999 Updates

    Acetonitrile (75-05-8) - The Chronic Oral RFD (RFDOC) has been withdrawn from IRIS. The Chronic Inhalation Reference Concentration (RFCIC) has been changed to 6.0E-2. The Chronic Inhalation Reference Dose has been changed to 1.71E-2. The cancer class changed to 'D'.

    Benzo(a)pyrene (50-32-8) - The Inhalation Unit Risk (IUR) has been corrected from 880 (g/m3) to 0.88 (mg/m3). This change affects all PAH's which derive their IUR values via a TEF.


    Compound TEF
    Benz(a)anthracene 0.1
    Benzo(b)fluoranthene 0.1
    Benzo(k)fluoranthene 0.01
    Chrysene 0.001
    Dibenz(a,h)anthracene 1.0
    Indeno(1,2,3-cd)pyrene 0.1

    October 1998 Updates

    Naphthalene (91-20-3) - The Chronic Oral RFD (RFDOC) changed to 2.0E-2 and the Chronic Inhalation Reference Concentration (RFCIC) changed to 3.0E-3. The cancer class changed to 'C'.

    Benzene (71-43-2) - The Inhalation Unit Risk (IUR) changed to 7.8E-3.


    September 1998 Updates

    Inhalation of soil now follows EPA's soil screening guidance and separates inhalation of volatiles and inhalation of particulates.

    Several new variables have been added to the Toxicity Values and Chemical-Specific Factors to accomodate the fields needed for soil inhalation. Included in this list are Inhalation Unit Risk factors.

    Inhalation chronic reference dose and reference concentration added for Naphthalene (91-20-3) [RFDIC = 3.71E-04, RFCIC = 1.3E-4] and Tetrachloroethylene (127-18-4) [RFDIC = 1.71E-01, RFCIC = 6.0E-1].

    Inhalation slope factor for Polycholorinated Biphenyls and all Aroclors has been changed from 2.0 to 0.4.

    Ingestion and dermal chronic reference dose have been changed for the following:

    Chemical CAS # RFDOC ADRFDOC
    Tricholorethane, 1,1,1 71-55-6 2.0E-1 1.8E-1
    Trichloroethylene 79-01-6 6.0E-3 9.0E-4
    Naphthalene 91-20-3 4.0E-2 3.2E-2
    Chromium (III) 16065-83-1 1.5E+0 7.5E-3

    EPA Cancer class changed for several analytes.

    References and footnotes changed for several analytes.

    New values added for Fish BTF (bio-transfer factor).

    New values added for Beef BTF (bio-transfer factor).

    New values added for Milk BTF (bio-transfer factor).

    New values added for KP (permeability constant).

    New values added for BV Dry for pasture

    New values added for BV Wet for leafy vegetables

    July '97 withdrawn dates added for:

    • Bis(2-ethylhexyl)phthalate (117-81-7)
    • Barium Cyanide (542-62-1)
    • Vinyl Bromide (593-60-2)
    • Cadmium (7440-43-9)
    • Chlorodibromoethane (73506-94-2)

    The ingestion rates used in the PRGs are now all expressed in kg/day.


    July 1998 Updates

    Inhalation RfDs are defined to be RfC x 20/70. A database check identified three inhalation reference doses which needed to be upddated. The following changes resulted:

    Chronic:
    101-68-8 Methylenediphenyl Diisocyanate
    OLD Number = 5.71E-6 NEW Number = 1.71E-4
     
    Subchronic:
    74-83-9 Bromomethane
    OLD Number = 4.77E-2 NEW Number = 1.4E-3
    108-88-3 Toluene
    OLD Number = 3.20E-1 NEW Number = 1.1E-1

    June 1998 Updates

    BERYLLIUM (7440-41-7) The oral slope factor is withdrawn pending further investigation.


    May 1998 Updates

    • BENTAZON (25057-89-0) The Chronic Oral RfD is changed from 2.50E-03 to 3.00E-02.
    • BERYLLIUM (7440-41-7) The chemical name is changed from "Beryllium" to "Beryllium and compounds". The Chronic Oral RfD is changed from 5.00E-03 to 2.00E-03. The Chronic Inhalation RfC of 2.00E-02 is added, and footnoted "a". The Chronic Dermal RfD is changed from 5.00E-05 to 2.00E-05.
    • CHLORDANE (57-74-9) The Chronic Oral RfD is changed from 6.00E-05 to 5.00E-04. The Oral Slope Factor is changed from 1.30E+00 to 3.50E-01. The Oral Unit Risk is changed from 3.70E-05 to 1.00E-05. The Chronic Inhalation RfC of 7.00E-04 with the footnote "a" is added. This is mutiplied by 20/70 to get a Chronic Inhalation RfD of 2.00E-4. The Inhalation Unit Risk is changed from 3.70E-04 to 1.00E-04. The Chronic Dermal RfD is changed from 3.00E-05 to 2.50E-04. The Dermal Slope Factor is changed from 2.60E+00 to 7.00E-01.
    • METHYL METHACRYLATE (80-62-6) The Chronic Oral RfD is changed from 8.00E-02 to 1.40E+00. The Chronic Inhalation RfC of 7.00E-01 with a footnote of "a" is added. This is mutiplied by 20/70 to get a Chronic Inhalation RfD of 2.00E-1.
    • METHYLENEDIPHENYL ISOCYANATE, 4,4'- (101-68-8) The chemical name is changed to Methylenediphenyl Diisocyanate. The Chronic Inhalation RfC is changed from 2.00E-05 to 6.00E-04.
    • POLYMERIC METHYLENE DIPHENYL DIISOCYANATE 9016-87-9 Polymeric Methylene Diphenyl Diisocyanate (PMDI) is added to the table. A Chronic Inhalation RfC of 6.00E-04 is listed and footnoted "a". The Subchronic Inhalation RfC is listed as 2.00E-05 and footnoted "b".

    February 1998 Updates

    • ANTIMONY TRIOXIDE (1309-64-4) A Subchronic Inhalation RfC value of 2.00E-04, with the footnote "b" has been added. This corresponds to an RfD of 5.71E-05.
    • ARSENIC, INORGANIC (7440-38-2) The Inhalation Slope Factor of 5.00E+01 has been withdrawn.
    • BENZO[B]FLUORANTHENE (205-99-2) The footnote "e" has been removed from the Subchronic Oral RfD field.
    • BORON AND BORATES ONLY (7440-42-8) The Subchronic Oral RfD value of 9.00E-02 and the Subchronic Dermal RfD value, 8.10E-02, have been withdrawn.
    • CARBON DISULFIDE (75-15-0) The Subchronic Inhalation RfC has been changed from 1.00E-02 to 7.00E-01. The footnote "b" remains unchanged. As a result, the RfD has been changed from 2.86E-03 to 2.0E-01.
    • CHLOROBENZENE (108-90-7) The Subchronic Oral RfD of 2.00E-01 and the Subchronic Dermal RfD value, 6.20E-02, have been withdrawn.
    • DICHLOROETHANE, 1, 2- (107-06-2) The Inhalation Slope Factor of 9.10E-02 has been withdrawn.
    • HYDROGEN SULFIDE (7783-06-4) The Subchronic Inhalation RfC has been changed from 9.00E-03 to 1.00E-02. The footnote "b" remains unchanged. As a result, the RfD has been changed from 2.57E-03 to 2.86E-03.
    • MANGANESE (Diet) (7439-96-5) The Subchronic Oral RfD value of 1.40E-01 and the Subchronic Dermal RfD value, 5.60E-03, have been withdrawn.
    • MANGANESE (Water) (7439-96-5) The Subchronic Oral RfD value of 5.00E-03 and the Subchronic Dermal RfD value, 2.00E-04, have been withdrawn.
    • MERCURIC CHLORIDE (7487-94-7) The Subchronic Oral RfD has been changed from 3.00E-04 to 3.00E-03. The Subchronic Dermal RfD is changed from 2.10E-05 to 2.10E-04.
    • PHOSPHINE (7803-51-2) The Subchronic Inhalation RfC has been changed from 3.00E-04 to 3.00E-03. The footnote "b" remains unchanged.
    • TRICHLOROETHANE, 1,1,1- (71-55-6) The footnote "e" has been removed from the Subchronic Inhalation RfC field.

    January 1998 Update

    The Risk-Based PRGs will now accept user-supplied parameters to the equations.


    October/November 1997 Updates

    • ACTINIUM-227+D (14952-40-0)+D The External Slope Factor has been changed from 5.97E-07 to 9.30E-07.
    • CALIFORNIUM-252 (13981-17-4) Californium-252 has been added to the table. The Radioactive Halflife is 2.64E+00 years. The ICRP Lung Class is Y. The GI Absorption Factor is 1.00E-03. The Ingestion Slope Factor is 1.80E-10. The Inhalation Slope Factor is 2.59E-08. The External Slope Factor is 1.79E-11.
    • CERIUM-144+D (14762-78-8)+D The External Slope Factor has been changed from 1.56E-07 to 1.59E-07.
    • CURIUM-243+D (15757-87-6)+D Curium-243+D has been removed.
    • IRIDIUM-192 (14694-69-0) Iridium-192 has been added to the table. The Radioactive Halflife is 7.40E+01 days. The ICRP Lung Class is Y. The GI Absorption Factor is 1.00E-02. The Ingestion Slope Factor is 6.43E-12. The Inhalation Slope Factor is 1.12E-11. The External Slope Factor is 2.70E-06.
    • PLUTONIUM-241+D (14119-32-5)+D Plutonium-241+D has been removed.
    • PLUTONIUM-244+D (14119-34-7)+D The External Slope Factor has been changed from 3.65E-06 to 1.05E-06.
    • SILVER-110m+D (14391-76-5)(m)+D Silver-110m+D has been added to the table. The Radioactive Halflife is 2.50E+02 days. The ICRP Lung Class is Y. The GI Absorption Factor is 5.00E-02. The Ingestion Slope Factor is 8.43E-12. The Inhalation Slope Factor is 3.21E-11. The External Slope Factor is 1.05E-05.
    • THALLIUM-207 (CAS number not available) Thallium-207 has been added to the table. The Radioactive Halflife is 4.77E+00 minutes. The ICRP Lung Class is D. The GI Absorption Factor is 9.50E-01. The Ingestion Slope Factor is 1.07E-14. The Inhalation Slope Factor is 1.24E-14. The External Slope Factor is 8.53E-09.
    • THORIUM-228+D (14274-82-9) The External Slope Factor has been changed from 9.94E-07 to 6.20E-06.
    • THORIUM-229+D (15594-54-4)+D The External Slope Factor has been changed from 5.99E-07 to 7.68E-07.
    • URANIUM-238+D (7440-61-1) The External Slope Factor has been changed from 5.25E-08 to 6.57E-08.
    • MANGANESE (7439-96-5) The Chronic Oral RfD is changed from 4.67E-02 ot 4.6E-02. Footnote m was modified to explain the reason for this change.
    • TRINITROBENZENE, 1,3,5- (99-35-4) The Chronic Oral RfD is changed from 5.00E-05 to 3.00E-02. Footnote a remains unchanged.
    • Footnote m (Toxicity Values) is changed to explain the rounding of the value. It now reads, "IRIS no longer separates values for manganese chronic RfDs into water and diet RfDs. The chronic oral RfD for the total oral intake of manganese is 1.40E-01. However, when assessing exposure to manganese from drinking water or soil, IRIS recommends using a modifying factor of 3, thereby lowering the RfD to 4.67E-02, which has been rounded to 4.6E-02. Rounding to 4.7E-02 is more accurate, but makes the value less conservative. HEAST values remain separated into water and diet subchronic RfDs."
    • Footnote n (Toxicity Values) is changed to correct problems with previous versions. In the previous versions, the entire sentence was scrambled by computer error. The footnote now reads, "The cancer potency of PCB mixtures is determined using a three-tiered approach that depends on the information available. Criteria for use of the High Risk and Persistence Tier include: food chain exposure; sediment or soil ingestion; dust or aerosol inhalation; dermal exposure if an absorption factor has been applied; any early-life exposure; and the presence of dioxin-like, tumor-promoting, or persistent congeners. This value, 2.00E+00 per (mg/kg)/day, is the upper-bound slope factor for the High Risk and Persistence Tier. The central-estimate slope factor for this tier is 1.00+00 per (mg/kg)/day."
    • Footnote r (Toxicity Values). A typographical error was corrected, removing the letter "c" from the word "cPAH", in the phrase "...used to convert each cPAH concentration...".

    November 1997

    Added Quantitative Uncertainty Analysis of Superfund Residential Risk Pathway Models for Soil and Goundwater: White Paper Oak Ridge National Laboratory, 1996 (pdf format).


    August/September 1997 Updates

    Many Permeability Constants (Kp) have been added.

    The halflives for Ruthenium were corrected in the the Excel spreadsheet.

    CUMENE (98-82-8) The chronic oral RfD is changed from 4.00E-02 to 1.00E-01. The footnote for this value, "a", remains unchanged. The chronic inhalation RfC is changed from 9.00E-03 to 4.00E-01, and footnoted a, indicating that the new value comes from IRIS. The EPA Cancer Classification of D is added, and footnoted a, indicating that it comes from IRIS.

    TRIBUTYLTIN OXIDE (56-35-9) The Chronic Oral RfD is changed from 3.00E-05 to 3.00E-04, with the footnote "a" remaining unchanged, indicating that the value comes from IRIS. An EPA Cancer Classification of D is added, footnoted "a". Note, the inhalation information added to the IRIS file indicated that data are inadequate for derivation of an inhalation RfC.


    May/June 1997 Updates

    • DIBROMOETHANE, 1,2- (106-93-4) The Inhalation Unit Risk of 2.20E-04 was added, with the footnote a, indicating that the value comes from IRIS. This is not a new value, it was mistakenly omitted from previous versions.
    • AMMONIA (7664-41-7) Oral Chronic and Subchronic RfD values, both 34 mg/l, were added. Both values are footnoted b and y.
    • Footnote c (Toxicity Values) is changed to reflect the HEAST definition for alternative methods. The new footnote reads, "These subchronic and chronic non-cancer toxicity values are found in Agency documents, but were calculated by alternative methods that are not currently practiced by the RfD/RfC Work Group. These values are considered to be adequate provisional values for risk assessment purposes at Superfund and RCRA sites, but are subject to being reviewed by the RfD/RfC Work Group and revised when necessary to reflect current work group practices."
    • Footnote y (Toxicity Values) is added to the table. It reads, "This value given as concentration in drinking water. Specifically related to organoleptic threshold. Safe concentration may be higher, but data are inadequate to assess."

    April 1997 Updates

    • The chemical-specific parameters have been updated for Methyl Mercury, Elemental Mercury, Mercury (Inorganic Salts), and Mercuric Sulfide.

    March 1997 Updates

    • The chemical-specific parameters have been updated.

    September 1996 Updates

    • The chemical-specific parameters have been updated.

    June 1996 Updates

    • The chemical-specific parameters have been updated.

    February 1996 Updates

    • The chemical-specific parameters have been updated.
    • Ingestion of Fish has been added as a pathway to the residential scenario.
    • Ingestion of Fish has been changed to include a concentration in fish and a concentration in water. There are new equations for both concentrations for both scenarios (recreational and residential).
    • A hazard quotient of 0.1 added to the database.
    • Averaging time for noncarcinogens has changed from 30x365 to EDx365.
    • Subchronic RfDs have been added to the chemical-specific parameters.
    • Indoor inhalation rate changed from 15 to 20 cubic meters per day for residential scenarios.
    • Water ingestion rate changed from 2 liters per day to .05 liters per hour for ingestion of water in the recreational scenario and the water pathway.
    • Exposure frequency changed from 75 to 45 days per year for dermal contact with water in the recreational scenario and the water pathway.
    • The exposure time (ET) in hours per day and the units conversion factor CF2) in days per hour have both been removed from several equations.
    • Agricultural Equations
      • New back-calculated equations for vegetables added.
      • New back-calculated equations for analyte concentrations in soil alone added.
      • New back-calculated equations for analyte concentrations in soil and water added.
      • New supporting equations for chemical concentration in vegetables and beef added.