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:

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:

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 (K_p) 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.