Sample records for exempt chemical mixtures

  1. 21 CFR 1310.12 - Exempt chemical mixtures.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 9 2014-04-01 2014-04-01 false Exempt chemical mixtures. 1310.12 Section 1310.12... CHEMICALS AND CERTAIN MACHINES § 1310.12 Exempt chemical mixtures. (a) The chemical mixtures meeting the..., or importation of listed chemicals contained in the exempt chemical mixture or the civil liability...

  2. 21 CFR 1310.12 - Exempt chemical mixtures.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 9 2013-04-01 2013-04-01 false Exempt chemical mixtures. 1310.12 Section 1310.12... CHEMICALS AND CERTAIN MACHINES § 1310.12 Exempt chemical mixtures. (a) The chemical mixtures meeting the..., or importation of listed chemicals contained in the exempt chemical mixture or the civil liability...

  3. 21 CFR 1310.12 - Exempt chemical mixtures.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 9 2012-04-01 2012-04-01 false Exempt chemical mixtures. 1310.12 Section 1310.12... CHEMICALS AND CERTAIN MACHINES § 1310.12 Exempt chemical mixtures. (a) The chemical mixtures meeting the..., or importation of listed chemicals contained in the exempt chemical mixture or the civil liability...

  4. 21 CFR 1310.12 - Exempt chemical mixtures.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Exempt chemical mixtures. 1310.12 Section 1310.12... CHEMICALS AND CERTAIN MACHINES § 1310.12 Exempt chemical mixtures. (a) The chemical mixtures meeting the... importation of listed chemicals contained in the exempt chemical mixture or the civil liability for unlawful...

  5. 21 CFR 1310.12 - Exempt chemical mixtures.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 9 2011-04-01 2011-04-01 false Exempt chemical mixtures. 1310.12 Section 1310.12... CHEMICALS AND CERTAIN MACHINES § 1310.12 Exempt chemical mixtures. (a) The chemical mixtures meeting the... importation of listed chemicals contained in the exempt chemical mixture or the civil liability for unlawful...

  6. 21 CFR 1310.13 - Exemption of chemical mixtures; application.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Exemption of chemical mixtures; application. 1310... REPORTS OF LISTED CHEMICALS AND CERTAIN MACHINES § 1310.13 Exemption of chemical mixtures; application. (a... application of all or any part of the Act a chemical mixture consisting of two or more chemical components, at...

  7. 21 CFR 1310.13 - Exemption of chemical mixtures; application.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 9 2011-04-01 2011-04-01 false Exemption of chemical mixtures; application. 1310... REPORTS OF LISTED CHEMICALS AND CERTAIN MACHINES § 1310.13 Exemption of chemical mixtures; application. (a... application of all or any part of the Act a chemical mixture consisting of two or more chemical components, at...

  8. 21 CFR 1310.13 - Exemption of chemical mixtures; application.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 9 2013-04-01 2013-04-01 false Exemption of chemical mixtures; application. 1310... REPORTS OF LISTED CHEMICALS AND CERTAIN MACHINES § 1310.13 Exemption of chemical mixtures; application. (a... application of all or any part of the Act a chemical mixture consisting of two or more chemical components, at...

  9. 21 CFR 1310.13 - Exemption of chemical mixtures; application.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 9 2014-04-01 2014-04-01 false Exemption of chemical mixtures; application. 1310... REPORTS OF LISTED CHEMICALS AND CERTAIN MACHINES § 1310.13 Exemption of chemical mixtures; application. (a... application of all or any part of the Act a chemical mixture consisting of two or more chemical components, at...

  10. 21 CFR 1310.13 - Exemption of chemical mixtures; application.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 9 2012-04-01 2012-04-01 false Exemption of chemical mixtures; application. 1310... REPORTS OF LISTED CHEMICALS AND CERTAIN MACHINES § 1310.13 Exemption of chemical mixtures; application. (a... application of all or any part of the Act a chemical mixture consisting of two or more chemical components, at...

  11. Elimination of exemptions for chemical mixtures containing the list I chemicals ephedrine and/or pseudoephedrine. Final rule.

    PubMed

    2008-07-10

    The Drug Enforcement Administration (DEA) is finalizing, without change, the Interim Rule with Request for Comment published in the Federal Register on July 25, 2007 (72 FR 40738). The Interim Rule removed the Controlled Substances Act (CSA) exemptions for chemical mixtures containing ephedrine and/or pseudoephedrine with concentration limits at or below five percent. Upon the effective date of the Interim Rule, all ephedrine and pseudoephedrine chemical mixtures, regardless of concentration and form, became subject to the regulatory provisions of the CSA. DEA regulated the importation, exportation, manufacture, and distribution of these chemical mixtures by requiring persons who handle these chemical mixtures to register with DEA, maintain certain records common to business practice, and file certain reports, regarding these chemical mixtures. No comments to the Interim Rule were received. This Final Rule finalizes the Interim Rule without change.

  12. 21 CFR 1308.24 - Exempt chemical preparations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 9 2011-04-01 2011-04-01 false Exempt chemical preparations. 1308.24 Section 1308... SUBSTANCES Exempt Chemical Preparations § 1308.24 Exempt chemical preparations. (a) The chemical preparations... security: Any person who manufactures an exempt chemical preparation or mixture must be registered under...

  13. 21 CFR 1308.24 - Exempt chemical preparations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Exempt chemical preparations. 1308.24 Section 1308... SUBSTANCES Exempt Chemical Preparations § 1308.24 Exempt chemical preparations. (a) The chemical preparations... security: Any person who manufactures an exempt chemical preparation or mixture must be registered under...

  14. 21 CFR 1308.24 - Exempt chemical preparations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 9 2012-04-01 2012-04-01 false Exempt chemical preparations. 1308.24 Section 1308... SUBSTANCES Exempt Chemical Preparations § 1308.24 Exempt chemical preparations. (a) The chemical preparations... security: Any person who manufactures an exempt chemical preparation or mixture must be registered under...

  15. 21 CFR 1308.24 - Exempt chemical preparations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 9 2014-04-01 2014-04-01 false Exempt chemical preparations. 1308.24 Section 1308... SUBSTANCES Exempt Chemical Preparations § 1308.24 Exempt chemical preparations. (a) The chemical preparations... security: Any person who manufactures an exempt chemical preparation or mixture must be registered under...

  16. 21 CFR 1308.24 - Exempt chemical preparations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 9 2013-04-01 2013-04-01 false Exempt chemical preparations. 1308.24 Section 1308... SUBSTANCES Exempt Chemical Preparations § 1308.24 Exempt chemical preparations. (a) The chemical preparations... security: Any person who manufactures an exempt chemical preparation or mixture must be registered under...

  17. 76 FR 41371 - Impact of Reducing the Mixture Concentration Threshold for Commercial Schedule 3 Chemical...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-13

    ...The Bureau of Industry and Security (BIS) is seeking public comments on the impact of amending the Chemical Weapons Convention Regulations (CWCR) to reduce the concentration level at which the CWCR exempt certain mixtures containing Schedule 3 chemicals from the declaration requirements that apply to Schedule 3 chemical production and the reporting requirements that apply to exports and imports of Schedule 3 chemicals under the Chemical Weapons Convention (CWC). BIS is considering amending the CWCR declaration requirements that apply to the production of Schedule 3 chemicals to conform with the low concentration exemption adopted by the Organization for the Prohibition of Chemical Weapons (OPCW) in 2003, which applies when the concentration of any single Schedule 3 chemical in a mixture is ``30% or less,'' by weight or volume (whichever yields the lesser percent). Currently, the CWCR do not require the quantity of a Schedule 3 chemical contained in a mixture to be counted for declaration or reporting purposes if the concentration of the Schedule 3 chemical in the mixture is ``less than 80%'' by volume or weight (whichever yields the lesser percent). The current low concentration level was implemented in accordance with requirements set forth in the Chemical Weapons Convention Implementation Act (CWCIA). Accordingly, publication and implementation of regulatory changes affecting this low concentration exemption level would be contingent upon amendment of the CWCIA by the Congress. In addition, consistent with U.S. national discretion, BIS is considering amending the CWCR reporting requirements for exports and imports of Schedule 3 chemicals by reducing the low concentration exemption that applies to certain mixtures containing Schedule 3 chemicals from the current low concentration level of ``less than 80%'' of a Schedule 3 chemical by volume or weight (whichever yields the lesser percent) to a concentration of ``30% or less.''

  18. 76 FR 31824 - Chemical Mixtures Containing Listed Forms of Phosphorus and Change in Application Process

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-02

    ... 1117-AA66 Chemical Mixtures Containing Listed Forms of Phosphorus and Change in Application Process... establish those chemical mixtures containing red phosphorus or hypophosphorous acid and its salts (hereinafter ``regulated phosphorus'') that shall automatically qualify for exemption from the [[Page 31825...

  19. 21 CFR 1310.09 - Temporary exemption from registration.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... manufacture, distribute, import, or export regulated iodine, including regulated iodine chemical mixtures... a chemical mixture containing iodine on or before August 31, 2007. The exemption will remain in... distributes, imports, or exports a chemical mixture containing iodine whose application for exemption is...

  20. 76 FR 41365 - Impact of Reducing the Mixture Concentration Threshold for Commercial Schedule 2A Chemical...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-13

    ...The Bureau of Industry and Security (BIS) is seeking public comments on the impact of amending the Chemical Weapons Convention Regulations (CWCR) to reduce the concentration level below which the CWCR exempt certain mixtures containing a Schedule 2A chemical from the declaration requirements that apply to Schedule 2A chemical production, processing, and consumption under the Chemical Weapons Convention (CWC). To make these declaration requirements consistent with the international agreement adopted by the Organization for the Prohibition of Chemical Weapons (OPCW), BIS is considering amending the CWCR to replace the current low concentration exemption (a concentration of ``less than 30%'' by volume or weight) with a two-tiered low concentration exemption that is based, in part, on whether the total amount of a Schedule 2A chemical produced, processed, or consumed at one or more plants on a plant site during a calendar year is less than the applicable verification threshold in the CWCR. Under this two- tiered approach, the declaration and reporting requirements in the CWCR would not apply to a chemical mixture containing a Schedule 2A chemical if: The concentration of the Schedule 2A chemical in the mixture is ``1% or less,'' or the concentration of the Schedule 2A chemical in the mixture is ``more than 1%, but less than or equal to 10%,'' and the annual amount of the Schedule 2A chemical produced, processed, or consumed is less than the relevant verification threshold. Legislative amendment of the Chemical Weapons Convention Implementation Act (CWCIA) is required in order to implement this proposed amendment to the CWCR. In addition, at U.S. national discretion, BIS is considering amending the CWCR to require declarations/reports for exports and imports of any mixtures that contain ``more than 10%'' of a Schedule 2A chemical by volume or weight (whichever method yields the lesser percentage), if the total quantity of the Schedule 2A chemical exported or imported

  1. 10 CFR 503.9 - Use of mixtures-general requirement for certain permanent exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... exemptions. 503.9 Section 503.9 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS NEW FACILITIES... and petroleum and an alternate fuel for which an exemption under 10 CFR 503.38 (Fuel mixtures) would... substitute mixture, such other alternate fuels as OFE and the petitioner agree are reasonable to petitioner's...

  2. 40 CFR 372.38 - Exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... person produced the mixture, either by mixing the chemicals involved or by causing a chemical reaction... COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.38 Exemptions. (a) De minimis concentrations of a toxic chemical in a mixture. If a toxic...

  3. 40 CFR 372.38 - Exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... person produced the mixture, either by mixing the chemicals involved or by causing a chemical reaction... COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.38 Exemptions. (a) De minimis concentrations of a toxic chemical in a mixture. If a toxic...

  4. 40 CFR 372.38 - Exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... person produced the mixture, either by mixing the chemicals involved or by causing a chemical reaction... COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.38 Exemptions. (a) De minimis concentrations of a toxic chemical in a mixture. If a toxic...

  5. 40 CFR 372.38 - Exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... person produced the mixture, either by mixing the chemicals involved or by causing a chemical reaction... COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.38 Exemptions. (a) De minimis concentrations of a toxic chemical in a mixture. If a toxic...

  6. 40 CFR 372.38 - Exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... person produced the mixture, either by mixing the chemicals involved or by causing a chemical reaction... COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.38 Exemptions. (a) De minimis concentrations of a toxic chemical in a mixture. If a toxic...

  7. 75 FR 36306 - Chemical Mixtures Containing Listed Forms of Phosphorus and Change in Application Process

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-25

    ... 1117-AA66 Chemical Mixtures Containing Listed Forms of Phosphorus and Change in Application Process... phosphorus, white phosphorus (also known as yellow phosphorus), or hypophosphorous acid and its salts (hereinafter ``regulated phosphorus'') that shall automatically qualify for exemption from the Controlled...

  8. 21 CFR 80.35 - Color additive mixtures; certification and exemption from certification.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Color additive mixtures; certification and... HEALTH AND HUMAN SERVICES GENERAL COLOR ADDITIVE CERTIFICATION Certification Procedures § 80.35 Color additive mixtures; certification and exemption from certification. (a) Color additive mixtures to be...

  9. 21 CFR 80.35 - Color additive mixtures; certification and exemption from certification.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Color additive mixtures; certification and... HEALTH AND HUMAN SERVICES GENERAL COLOR ADDITIVE CERTIFICATION Certification Procedures § 80.35 Color additive mixtures; certification and exemption from certification. (a) Color additive mixtures to be...

  10. 21 CFR 80.35 - Color additive mixtures; certification and exemption from certification.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Color additive mixtures; certification and... HEALTH AND HUMAN SERVICES GENERAL COLOR ADDITIVE CERTIFICATION Certification Procedures § 80.35 Color additive mixtures; certification and exemption from certification. (a) Color additive mixtures to be...

  11. 21 CFR 73.1001 - Diluents in color additive mixtures for drug use exempt from certification.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Diluents in color additive mixtures for drug use..., DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1001 Diluents in color additive mixtures for drug use exempt from certification. The following...

  12. 21 CFR 73.1 - Diluents in color additive mixtures for food use exempt from certification.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Diluents in color additive mixtures for food use... HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.1 Diluents in color additive mixtures for food use exempt from certification. The following substances may be...

  13. 21 CFR 73.1 - Diluents in color additive mixtures for food use exempt from certification.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Diluents in color additive mixtures for food use... HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.1 Diluents in color additive mixtures for food use exempt from certification. The following substances may be...

  14. 21 CFR 73.1 - Diluents in color additive mixtures for food use exempt from certification.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Diluents in color additive mixtures for food use... HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.1 Diluents in color additive mixtures for food use exempt from certification. The following substances may be...

  15. 21 CFR 73.1 - Diluents in color additive mixtures for food use exempt from certification.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Diluents in color additive mixtures for food use... HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.1 Diluents in color additive mixtures for food use exempt from certification. The following substances may be...

  16. 21 CFR 73.1 - Diluents in color additive mixtures for food use exempt from certification.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Diluents in color additive mixtures for food use... HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.1 Diluents in color additive mixtures for food use exempt from certification. The following substances may be...

  17. 40 CFR 180.905 - Pesticide chemicals; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Pesticide chemicals; exemptions from... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.905 Pesticide chemicals; exemptions from the requirement of a...

  18. 40 CFR 180.905 - Pesticide chemicals; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Pesticide chemicals; exemptions from... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.905 Pesticide chemicals; exemptions from the requirement of a...

  19. 40 CFR 180.905 - Pesticide chemicals; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Pesticide chemicals; exemptions from... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.905 Pesticide chemicals; exemptions from the requirement of a...

  20. 40 CFR 180.1317 - Pesticide chemicals; exemption from the requirements of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Pesticide chemicals; exemption from... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1317 Pesticide chemicals; exemption from the requirements of a...

  1. 40 CFR 180.1317 - Pesticide chemicals; exemption from the requirements of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Pesticide chemicals; exemption from... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1317 Pesticide chemicals; exemption from the requirements of a...

  2. 40 CFR 180.905 - Pesticide chemicals; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Pesticide chemicals; exemptions from... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.905 Pesticide chemicals; exemptions from the requirement of a...

  3. 40 CFR 180.905 - Pesticide chemicals; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Pesticide chemicals; exemptions from... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.905 Pesticide chemicals; exemptions from the requirement of a...

  4. Partial Exemption of Certain Chemical Substances from Reporting Additional Chemical Data

    EPA Pesticide Factsheets

    This Federal Register notice amends the list of chemical substances that are partially exempt from reporting additional information by adding six chemicals in response to a petition the Agency received.

  5. 21 CFR 73.1001 - Diluents in color additive mixtures for drug use exempt from certification.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Diluents in color additive mixtures for drug use exempt from certification. 73.1001 Section 73.1001 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs...

  6. 21 CFR 73.1001 - Diluents in color additive mixtures for drug use exempt from certification.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Diluents in color additive mixtures for drug use exempt from certification. 73.1001 Section 73.1001 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs...

  7. 21 CFR 73.1001 - Diluents in color additive mixtures for drug use exempt from certification.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Diluents in color additive mixtures for drug use exempt from certification. 73.1001 Section 73.1001 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs...

  8. 21 CFR 73.1001 - Diluents in color additive mixtures for drug use exempt from certification.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Diluents in color additive mixtures for drug use exempt from certification. 73.1001 Section 73.1001 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs...

  9. 21 CFR 1310.16 - Exemptions for certain scheduled listed chemical products.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 9 2011-04-01 2011-04-01 false Exemptions for certain scheduled listed chemical... RECORDS AND REPORTS OF LISTED CHEMICALS AND CERTAIN MACHINES § 1310.16 Exemptions for certain scheduled listed chemical products. (a) Upon the application of a manufacturer of a scheduled listed chemical...

  10. 10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... mixture of solar energy (including wind, tide, and other intermittent sources) and petroleum or natural gas, where: (1) Solar energy will account for at least 20 percent of the total annual Btu heat input... 10 Energy 4 2011-01-01 2011-01-01 false Permanent exemption for certain fuel mixtures containing...

  11. 10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... mixture of solar energy (including wind, tide, and other intermittent sources) and petroleum or natural gas, where: (1) Solar energy will account for at least 20 percent of the total annual Btu heat input... 10 Energy 4 2012-01-01 2012-01-01 false Permanent exemption for certain fuel mixtures containing...

  12. 10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... mixture of solar energy (including wind, tide, and other intermittent sources) and petroleum or natural gas, where: (1) Solar energy will account for at least 20 percent of the total annual Btu heat input... 10 Energy 4 2013-01-01 2013-01-01 false Permanent exemption for certain fuel mixtures containing...

  13. 10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... mixture of solar energy (including wind, tide, and other intermittent sources) and petroleum or natural gas, where: (1) Solar energy will account for at least 20 percent of the total annual Btu heat input... 10 Energy 4 2014-01-01 2014-01-01 false Permanent exemption for certain fuel mixtures containing...

  14. 30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

  15. 30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

  16. 30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

  17. 30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

  18. 30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

  19. Test Marketing Exemption (TME) for New Chemical Review under TSCA

    EPA Pesticide Factsheets

    Under section 5 of TSCA, EPA established an exemption for certain chemicals that are manufactured (including imported) for test marketing. You can learn more here about the requirements of this exemption, along with the review and submission process.

  20. Research and Development Exemption for New Chemical Review under TSCA

    EPA Pesticide Factsheets

    Section 5(h)(3) of TSCA allows EPA to exempt manufacturers of chemical substances from the notice requirements if they manufacture it in small quantities for the purposed of research and development. This page gives an overview of this exemption.

  1. Designation of Alpha-Phenylacetoacetonitrile (APAAN), a Precursor Chemical Used in the Illicit Manufacture of Phenylacetone, Methamphetamine, and Amphetamine, as a List I Chemical. Final rule.

    PubMed

    2017-07-14

    The Drug Enforcement Administration (DEA) is finalizing the designation of the chemical alpha-phenylacetoacetonitrile (APAAN) and its salts, optical isomers, and salts of optical isomers, as a list I chemical under the Controlled Substances Act (CSA). The DEA proposed control of APAAN, due to its use in clandestine laboratories to illicitly manufacture the schedule II controlled substances phenylacetone (also known as phenyl-2-propanone or P2P), methamphetamine, and amphetamine. This rulemaking finalizes, without change, the control of APAAN as a list I chemical. This action does not establish a threshold for domestic and international transactions of APAAN. As such, all transactions involving APAAN, regardless of size, shall be regulated. In addition, chemical mixtures containing APAAN are not exempt from regulatory requirements at any concentration. Therefore, all transactions of chemical mixtures containing any quantity of APAAN shall be regulated pursuant to the CSA. However, manufacturers may submit an application for exemption for those mixtures that do not qualify for automatic exemption.

  2. Low Volume Exemption for New Chemical Review under TSCA

    EPA Pesticide Factsheets

    Certain categories of new low-volume chemical substances are exempt from full premanufacture notice (PMN) review, i.e., chemicals manufactured at 10,000 kg/year or less. LVE substances undergo a 30-day review and are not subject to a user fee.

  3. Cumulative effects of anti-androgenic chemical mixtures and ...

    EPA Pesticide Factsheets

    Kembra L. Howdeshell and L. Earl Gray, Jr.Toxicological studies of defined chemical mixtures assist human health risk assessment by characterizing the joint action of chemicals. This presentation will review the effects of anti-androgenic chemical mixtures on reproductive tract development in rats with a special focus on the reproductive toxicant phthalates. Observed mixture data are compared to mathematical mixture model predictions to determine how the individual chemicals in a mixture interact (e.g., response addition – probabilities of response for each individual chemical are added; dose-addition – the doses of each individual chemical at a given mixture dose are combined together based on the relative potency of the individual chemicals). Phthalate mixtures are observed to act in a dose-additive manner based on the relative potency of the individual phthalates to suppress fetal testosterone production. Similar dose-additive effects have been reported for mixtures of phthalates with anti-androgenic pesticides of differing mechanisms. Data from these phthalate experiments in rats can be used in conjunction with human biomonitoring data to determine individual hazard ratios. Furthermore, data from the toxicological studies can inform the analysis of human biomonitoring data on the association of detected chemicals and their metabolites with measured health outcomes. Data from phthalate experiments in rats can be used in conjunction with human biomonit

  4. Understanding the human health effects of chemical mixtures.

    PubMed Central

    Carpenter, David O; Arcaro, Kathleen; Spink, David C

    2002-01-01

    Most research on the effects of chemicals on biologic systems is conducted on one chemical at a time. However, in the real world people are exposed to mixtures, not single chemicals. Although various substances may have totally independent actions, in many cases two substances may act at the same site in ways that can be either additive or nonadditive. Many even more complex interactions may occur if two chemicals act at different but related targets. In the extreme case there may be synergistic effects, in which case the effects of two substances together are greater than the sum of either effect alone. In reality, most persons are exposed to many chemicals, not just one or two, and therefore the effects of a chemical mixture are extremely complex and may differ for each mixture depending on the chemical composition. This complexity is a major reason why mixtures have not been well studied. In this review we attempt to illustrate some of the principles and approaches that can be used to study effects of mixtures. By the nature of the state of the science, this discussion is more a presentation of what we do not know than of what we do know about mixtures. We approach the study of mixtures at three levels, using specific examples. First, we discuss several human diseases in relation to a variety of environmental agents believed to influence the development and progression of the disease. We present results of selected cellular and animal studies in which simple mixtures have been investigated. Finally, we discuss some of the effects of mixtures at a molecular level. PMID:11834461

  5. Ecological Assembly of Chemical Mixtures

    EPA Science Inventory

    Human-environment interactions have a significant role in the formation of chemical mixtures in the environment and by extension in human tissues and fluids. These interactions, which include decisions to purchase and use products containing chemicals as well as behaviors and act...

  6. Low Releases and Low Exposures (LoREX) Exemption for New Chemicals Review under TSCA

    EPA Pesticide Factsheets

    EPA established an exemption category for certain new chemical substances with low environmental releases and human exposures. To ensure that they will not present an unreasonable risk, EPA has included a 30-day review and other conditions in the exemption

  7. New Chemical Information Bulletin: Exemptions for Research and Development and Test Marketing

    EPA Pesticide Factsheets

    EPA has received numerous questions about the scope of the exemption for R&D, under TSCA section 5(h)(3). This New Chemical Information Bulletin provides more specific guidance to manufacturers and processors of new chemical substances.

  8. Chemical mixtures in potable water in the U.S.

    USGS Publications Warehouse

    Ryker, Sarah J.

    2014-01-01

    In recent years, regulators have devoted increasing attention to health risks from exposure to multiple chemicals. In 1996, the US Congress directed the US Environmental Protection Agency (EPA) to study mixtures of chemicals in drinking water, with a particular focus on potential interactions affecting chemicals' joint toxicity. The task is complicated by the number of possible mixtures in drinking water and lack of toxicological data for combinations of chemicals. As one step toward risk assessment and regulation of mixtures, the EPA and the Agency for Toxic Substances and Disease Registry (ATSDR) have proposed to estimate mixtures' toxicity based on the interactions of individual component chemicals. This approach permits the use of existing toxicological data on individual chemicals, but still requires additional information on interactions between chemicals and environmental data on the public's exposure to combinations of chemicals. Large compilations of water-quality data have recently become available from federal and state agencies. This chapter demonstrates the use of these environmental data, in combination with the available toxicological data, to explore scenarios for mixture toxicity and develop priorities for future research and regulation. Occurrence data on binary and ternary mixtures of arsenic, cadmium, and manganese are used to parameterize the EPA and ATSDR models for each drinking water source in the dataset. The models' outputs are then mapped at county scale to illustrate the implications of the proposed models for risk assessment and rulemaking. For example, according to the EPA's interaction model, the levels of arsenic and cadmium found in US groundwater are unlikely to have synergistic cardiovascular effects in most areas of the country, but the same mixture's potential for synergistic neurological effects merits further study. Similar analysis could, in future, be used to explore the implications of alternative risk models for the

  9. Chemical Mixtures Health Risk Assessment: Overview of Exposure Assessment, Whole Mixtures Assessments; Basic Concepts

    EPA Science Inventory

    This problems-based, half-day, introductory workshop focuses on methods to assess health risks posed by exposures to chemical mixtures in the environment. Chemical mixtures health risk assessment methods continue to be developed and evolve to address concerns over health risks f...

  10. 30 CFR 47.92 - Exemptions from labeling.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... COMMUNICATION (HazCom) Exemptions § 47.92 Exemptions from labeling. A hazardous chemical is exempt from subpart... Chemicals Exempt from Labeling Exemption Conditions for exemption Chemical substance, consumer product, hazardous substance, or pesticide When kept in its manufacturer's or supplier's original packaging labeled...

  11. 30 CFR 47.92 - Exemptions from labeling.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... COMMUNICATION (HazCom) Exemptions § 47.92 Exemptions from labeling. A hazardous chemical is exempt from subpart... Chemicals Exempt from Labeling Exemption Conditions for exemption Chemical substance, consumer product, hazardous substance, or pesticide When kept in its manufacturer's or supplier's original packaging labeled...

  12. 30 CFR 47.92 - Exemptions from labeling.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... COMMUNICATION (HazCom) Exemptions § 47.92 Exemptions from labeling. A hazardous chemical is exempt from subpart... Chemicals Exempt from Labeling Exemption Conditions for exemption Chemical substance, consumer product, hazardous substance, or pesticide When kept in its manufacturer's or supplier's original packaging labeled...

  13. 30 CFR 47.92 - Exemptions from labeling.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... COMMUNICATION (HazCom) Exemptions § 47.92 Exemptions from labeling. A hazardous chemical is exempt from subpart... Chemicals Exempt from Labeling Exemption Conditions for exemption Chemical substance, consumer product, hazardous substance, or pesticide When kept in its manufacturer's or supplier's original packaging labeled...

  14. MODEL OF ADDITIVE EFFECTS OF MIXTURES OF NARCOTIC CHEMICALS

    EPA Science Inventory

    Biological effects data with single chemicals are far more abundant than with mixtures. et, environmental exposures to chemical mixtures, for example near hazardous waste sites or nonpoint sources, are very common and using test data from single chemicals to approximate effects o...

  15. Chemical Mixture Risk Assessment Additivity-Based Approaches

    EPA Science Inventory

    Powerpoint presentation includes additivity-based chemical mixture risk assessment methods. Basic concepts, theory and example calculations are included. Several slides discuss the use of "common adverse outcomes" in analyzing phthalate mixtures.

  16. Health Risk Assessment of Chemical Mixtures

    EPA Science Inventory

    The implementation of Superfund requires a methodology for estimating health risk from multi-chemical contamination at ambient levels. Most often, the chemical composition of these mixtures is poorly characterized, exposure data are uncertain and toxicologic data on the known com...

  17. Prospective aquatic risk assessment for chemical mixtures in agricultural landscapes

    PubMed Central

    Brown, Colin D.; Hamer, Mick; Jones, Russell; Maltby, Lorraine; Posthuma, Leo; Silberhorn, Eric; Teeter, Jerold Scott; Warne, Michael St J; Weltje, Lennart

    2018-01-01

    Abstract Environmental risk assessment of chemical mixtures is challenging because of the multitude of possible combinations that may occur. Aquatic risk from chemical mixtures in an agricultural landscape was evaluated prospectively in 2 exposure scenario case studies: at field scale for a program of 13 plant‐protection products applied annually for 20 yr and at a watershed scale for a mixed land‐use scenario over 30 yr with 12 plant‐protection products and 2 veterinary pharmaceuticals used for beef cattle. Risk quotients were calculated from regulatory exposure models with typical real‐world use patterns and regulatory acceptable concentrations for individual chemicals. The results could differentiate situations when there was concern associated with single chemicals from those when concern was associated with a mixture (based on concentration addition) with no single chemical triggering concern. Potential mixture risk was identified on 0.02 to 7.07% of the total days modeled, depending on the scenario, the taxa, and whether considering acute or chronic risk. Taxa at risk were influenced by receiving water body characteristics along with chemical use profiles and associated properties. The present study demonstrates that a scenario‐based approach can be used to determine whether mixtures of chemicals pose risks over and above any identified using existing approaches for single chemicals, how often and to what magnitude, and ultimately which mixtures (and dominant chemicals) cause greatest concern. Environ Toxicol Chem 2018;37:674–689. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. PMID:29193235

  18. A role of low dose chemical mixtures in adipose tissue in carcinogenesis.

    PubMed

    Lee, Duk-Hee; Jacobs, David R; Park, Ho Yong; Carpenter, David O

    2017-11-01

    The Halifax project recently hypothesized a composite carcinogenic potential of the mixture of low dose chemicals which are commonly encountered environmentally, yet which are not classified as human carcinogens. A long neglected but important fact is that adipose tissue is an important exposure source for chemical mixtures. In fact, findings from human studies based on several persistent organic pollutants in general populations with only background exposure should be interpreted from the viewpoint of chemical mixtures because serum concentrations of these chemicals can be seen as surrogates for chemical mixtures in adipose tissue. Furthermore, in conditions such as obesity with dysfunctional adipocytes or weight loss in which lipolysis is increased, the amount of the chemical mixture released from adipose tissue to circulation is increased. Thus, both obesity and weight loss can enhance the chance of chemical mixtures reaching critical organs, however paradoxical this idea may be when fat mass is the only factor considered. The complicated, interrelated dynamics of adipocytes and chemical mixtures can explain puzzling findings related to body weight among cancer patients, including the obesity paradox. The contamination of fat in human diet with chemical mixtures, occurring for reasons similar to contamination of human adipose tissue, may be a missing factor which affects the association between dietary fat intake and cancer. The presence of chemical mixtures in adipose tissue should be considered in future cancer research, including clinical trials on weight management among cancer survivors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. 76 FR 16353 - International Traffic in Arms Regulations: Exemption for Temporary Export of Chemical Agent...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-23

    ... removing certain extraneous language that does not change the meaning of the exemption. DATES: The... need to wear body armor or chemical agent protective gear for personal safety. In August 2009, the ITAR was amended to provide an exemption for the temporary export of body armor covered by 22 CFR 121.1...

  20. Prospective aquatic risk assessment for chemical mixtures in agricultural landscapes.

    PubMed

    Holmes, Christopher M; Brown, Colin D; Hamer, Mick; Jones, Russell; Maltby, Lorraine; Posthuma, Leo; Silberhorn, Eric; Teeter, Jerold Scott; Warne, Michael St J; Weltje, Lennart

    2018-03-01

    Environmental risk assessment of chemical mixtures is challenging because of the multitude of possible combinations that may occur. Aquatic risk from chemical mixtures in an agricultural landscape was evaluated prospectively in 2 exposure scenario case studies: at field scale for a program of 13 plant-protection products applied annually for 20 yr and at a watershed scale for a mixed land-use scenario over 30 yr with 12 plant-protection products and 2 veterinary pharmaceuticals used for beef cattle. Risk quotients were calculated from regulatory exposure models with typical real-world use patterns and regulatory acceptable concentrations for individual chemicals. The results could differentiate situations when there was concern associated with single chemicals from those when concern was associated with a mixture (based on concentration addition) with no single chemical triggering concern. Potential mixture risk was identified on 0.02 to 7.07% of the total days modeled, depending on the scenario, the taxa, and whether considering acute or chronic risk. Taxa at risk were influenced by receiving water body characteristics along with chemical use profiles and associated properties. The present study demonstrates that a scenario-based approach can be used to determine whether mixtures of chemicals pose risks over and above any identified using existing approaches for single chemicals, how often and to what magnitude, and ultimately which mixtures (and dominant chemicals) cause greatest concern. Environ Toxicol Chem 2018;37:674-689. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

  1. Software for analysis of chemical mixtures--composition, occurrence, distribution, and possible toxicity

    USGS Publications Warehouse

    Scott, Jonathon C.; Skach, Kenneth A.; Toccalino, Patricia L.

    2013-01-01

    The composition, occurrence, distribution, and possible toxicity of chemical mixtures in the environment are research concerns of the U.S. Geological Survey and others. The presence of specific chemical mixtures may serve as indicators of natural phenomena or human-caused events. Chemical mixtures may also have ecological, industrial, geochemical, or toxicological effects. Chemical-mixture occurrences vary by analyte composition and concentration. Four related computer programs have been developed by the National Water-Quality Assessment Program of the U.S. Geological Survey for research of chemical-mixture compositions, occurrences, distributions, and possible toxicities. The compositions and occurrences are identified for the user-supplied data, and therefore the resultant counts are constrained by the user’s choices for the selection of chemicals, reporting limits for the analytical methods, spatial coverage, and time span for the data supplied. The distribution of chemical mixtures may be spatial, temporal, and (or) related to some other variable, such as chemical usage. Possible toxicities optionally are estimated from user-supplied benchmark data. The software for the analysis of chemical mixtures described in this report is designed to work with chemical-analysis data files retrieved from the U.S. Geological Survey National Water Information System but can also be used with appropriately formatted data from other sources. Installation and usage of the mixture software are documented. This mixture software was designed to function with minimal changes on a variety of computer-operating systems. To obtain the software described herein and other U.S. Geological Survey software, visit http://water.usgs.gov/software/.

  2. 21 CFR 1308.34 - Exempt anabolic steroid products.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 9 2012-04-01 2012-04-01 false Exempt anabolic steroid products. 1308.34 Section... SUBSTANCES Exempt Anabolic Steroid Products § 1308.34 Exempt anabolic steroid products. The list of compounds, mixtures, or preparations that contain an anabolic steroid that have been exempted by the Administrator...

  3. 21 CFR 1308.34 - Exempt anabolic steroid products.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 9 2014-04-01 2014-04-01 false Exempt anabolic steroid products. 1308.34 Section... SUBSTANCES Exempt Anabolic Steroid Products § 1308.34 Exempt anabolic steroid products. The list of compounds, mixtures, or preparations that contain an anabolic steroid that have been exempted by the Administrator...

  4. 21 CFR 1308.34 - Exempt anabolic steroid products.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 9 2011-04-01 2011-04-01 false Exempt anabolic steroid products. 1308.34 Section... SUBSTANCES Exempt Anabolic Steroid Products § 1308.34 Exempt anabolic steroid products. The list of compounds, mixtures, or preparations that contain an anabolic steroid that have been exempted by the Administrator...

  5. 21 CFR 1308.34 - Exempt anabolic steroid products.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 9 2013-04-01 2013-04-01 false Exempt anabolic steroid products. 1308.34 Section... SUBSTANCES Exempt Anabolic Steroid Products § 1308.34 Exempt anabolic steroid products. The list of compounds, mixtures, or preparations that contain an anabolic steroid that have been exempted by the Administrator...

  6. 21 CFR 1308.34 - Exempt anabolic steroid products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Exempt anabolic steroid products. 1308.34 Section... SUBSTANCES Exempt Anabolic Steroid Products § 1308.34 Exempt anabolic steroid products. The list of compounds, mixtures, or preparations that contain an anabolic steroid that have been exempted by the Administrator...

  7. The underlying toxicological mechanism of chemical mixtures: A case study on mixture toxicity of cyanogenic toxicants and aldehydes to Photobacterium phosphoreum

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tian, Dayong; Department of Chemical and Environmental Engineering, Anyang Institute of Technology, Anyang 455000; Lin, Zhifen, E-mail: lzhifen@tongji.edu.cn

    Intracellular chemical reaction of chemical mixtures is one of the main reasons that cause synergistic or antagonistic effects. However, it still remains unclear what the influencing factors on the intracellular chemical reaction are, and how they influence on the toxicological mechanism of chemical mixtures. To reveal this underlying toxicological mechanism of chemical mixtures, a case study on mixture toxicity of cyanogenic toxicants and aldehydes to Photobacterium phosphoreum was employed, and both their joint effects and mixture toxicity were observed. Then series of two-step linear regressions were performed to describe the relationships between joint effects, the expected additive toxicities and descriptorsmore » of individual chemicals (including concentrations, binding affinity to receptors, octanol/water partition coefficients). Based on the quantitative relationships, the underlying joint toxicological mechanisms were revealed. The result shows that, for mixtures with their joint effects resulting from intracellular chemical reaction, their underlying toxicological mechanism depends on not only their interaction with target proteins, but also their transmembrane actions and their concentrations. In addition, two generic points of toxicological mechanism were proposed including the influencing factors on intracellular chemical reaction and the difference of the toxicological mechanism between single reactive chemicals and their mixtures. This study provided an insight into the understanding of the underlying toxicological mechanism for chemical mixtures with intracellular chemical reaction. - Highlights: • Joint effects of nitriles and aldehydes at non-equitoxic ratios were determined. • A novel descriptor, ligand–receptor interaction energy (E{sub binding}), was employed. • Quantitative relationships for mixtures were developed based on a novel descriptor. • The underlying toxic mechanism was revealed based on quantitative relationships.

  8. Influence factors of multicomponent mixtures containing reactive chemicals and their joint effects.

    PubMed

    Tian, Dayong; Lin, Zhifen; Yu, Jianqiao; Yin, Daqiang

    2012-08-01

    Organic chemicals usually coexist as a mixture in the environment, and the mixture toxicity of organic chemicals has received increased attention. However, research regarding the joint effects of reactive chemicals is lacking. In this study, we examined two kinds of reactive chemicals, cyanogenic toxicants and aldehydes and determined their joint effects on Photobacterium phosphoreum. Three factors were found to influence the joint effects of multicomponent mixtures containing reactive chemicals, including the number of components, the dominating components and the toxic ratios. With an increased number of components, the synergistic or antagonistic effects (interactions) will weaken to the additive effects (non-interactions) if the added component cannot yield a much stronger joint effect with an existing component. Contrarily, the joint effect of the mixture may become stronger instead of weaker if the added components can yield a much stronger joint effect than the existing joint effect of the multicomponent mixture. The components that yield the strongest interactions in their binary mixture can be considered the dominating components. These components contribute more to the interactions of multicomponent mixtures than other components. Moreover, the toxic ratios also influence the joint effects of the mixtures. This study provides an insight into what are the main factors and how they influence the joint effects of multicomponent mixtures containing reactive chemicals, and thus, the findings are beneficial to the study of mixture toxicology. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. 21 CFR 1310.16 - Exemptions for certain scheduled listed chemical products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Exemptions for certain scheduled listed chemical products. 1310.16 Section 1310.16 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE... chapter if the Administrator determines that the product cannot be used in the illicit manufacture of a...

  10. GENE INDUCTION STUDIES AND TOXICITY OF CHEMICAL MIXTURES

    EPA Science Inventory

    As part of its mixtures program the Agency for Toxic Substances and Disease Registry (ATSDR) supports in vitro and limited in vivo toxicity testing to further our understanding of the toxicity and health effects of chemical mixtures. There are increasing concerns that environment...

  11. Computing Properties Of Chemical Mixtures At Equilibrium

    NASA Technical Reports Server (NTRS)

    Mcbride, B. J.; Gordon, S.

    1995-01-01

    Scientists and engineers need data on chemical equilibrium compositions to calculate theoretical thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93 is general program that calculates chemical equilibrium compositions and properties of mixtures for any chemical system for which thermodynamic data are available. Includes thermodynamic data for more than 1,300 gaseous and condensed species and thermal-transport data for 151 gases. Written in FORTRAN 77.

  12. Chemical Mixtures Health Risk Assessment of Environmental Contaminants: Concepts, Methods, Applications

    EPA Science Inventory

    This problems-based, introductory workshop focuses on methods to assess health risks posed by exposures to chemical mixtures in the environment. Chemical mixtures health risk assessment methods continue to be developed and evolve to address concerns over health risks from multic...

  13. Some critical issues and concerns related to research advances on toxicology of chemical mixtures.

    PubMed Central

    Yang, R S

    1998-01-01

    This paper addresses some of the issues and concerns on research advances on the toxicology of chemical mixtures. Emphases will be selectively given to the following questions and answers: Can mechanistic studies be conducted on chemical mixtures? The fact that any studies, including mechanistic studies, of single chemicals are really the study of the parent chemical plus its metabolites underscores the relevance of mechanistic studies on chemical mixtures. Can predictions be made on the health effects of chemical mixtures? Some successes are already evident in the literature on simpler chemical mixtures. For more complex mixtures, it is possible and we propose an approach here. What can we learn from other disciplines (the importance of interdisciplinary collaboration)? Two aspects, the knowledge and methodologies available in clinical pharmacology and the latest advances in structure-oriented lumping in chemical engineering, are discussed in detail. Unrepeatable results: The possibility of magnification of biologic variability because of low-level exposures to chemical mixtures is suggested with special reference to some known examples, including the controversial study on synergistic interactions of endocrine disruptors. Is the driving force for scientific investigations on chemical mixtures the legislative and regulatory atmosphere? Two laws with chemical mixtures specifically in the language are quoted and discussed. Their implications regarding research funding and activities are described. What are the pitfalls of applying for research funding on investigating chemical mixtures? The dilemma at least one investigator faces in pursuing research funding is elaborated. The questions and issues listed above are not all inclusive, but they represent some of the aspects that need to be brought into the open in the scientific community for discussion and/or debate. Thus, the primary objective of this paper is to provide some momentum for the beginning of a fruitful

  14. Advances in Chemical Mixtures Risk Methods

    EPA Science Inventory

    This presentation is an overview of emerging issues for dose addition in chemical mixtures risk assessment. It is intended to give the participants a perspective of recent developments in methods for dose addition. The workshop abstract is as follows:This problems-based, half-day...

  15. Cumulative effects of antiandrogenic chemical mixtures and their relevance to human health risk assessment.

    PubMed

    Howdeshell, Kembra L; Hotchkiss, Andrew K; Gray, L Earl

    2017-03-01

    Toxicological studies of defined chemical mixtures assist human health risk assessment by establishing how chemicals interact with one another to induce an effect. This paper reviews how antiandrogenic chemical mixtures can alter reproductive tract development in rats with a focus on the reproductive toxicant phthalates. The reviewed studies compare observed mixture data to mathematical mixture model predictions based on dose addition or response addition to determine how the individual chemicals in a mixture interact (e.g., additive, greater, or less than additive). Phthalate mixtures were observed to act in a dose additive manner based on the relative potency of the individual phthalates to suppress fetal testosterone production. Similar dose additive effects have been reported for mixtures of phthalates with antiandrogenic pesticides of differing mechanisms of action. Overall, data from these phthalate experiments in rats can be used in conjunction with human biomonitoring data to determine individual hazard indices, and recent cumulative risk assessments in humans indicate an excess risk to antiandrogenic chemical mixtures that include phthalates only or phthalates in combination with other antiandrogenic chemicals. Published by Elsevier GmbH.

  16. Thermo-Chemical Conversion of Microwave Activated Biomass Mixtures

    NASA Astrophysics Data System (ADS)

    Barmina, I.; Kolmickovs, A.; Valdmanis, R.; Vostrikovs, S.; Zake, M.

    2018-05-01

    Thermo-chemical conversion of microwave activated wheat straw mixtures with wood or peat pellets is studied experimentally with the aim to provide more effective application of wheat straw for heat energy production. Microwave pre-processing of straw pellets is used to provide a partial decomposition of the main constituents of straw and to activate the thermo-chemical conversion of wheat straw mixtures with wood or peat pellets. The experimental study includes complex measurements of the elemental composition of biomass pellets (wheat straw, wood, peat), DTG analysis of their thermal degradation, FTIR analysis of the composition of combustible volatiles entering the combustor, the flame temperature, the heat output of the device and composition of the products by comparing these characteristics for mixtures with unprocessed and mw pre-treated straw pellets. The results of experimental study confirm that mw pre-processing of straw activates the thermal decomposition of mixtures providing enhanced formation of combustible volatiles. This leads to improvement of the combustion conditions in the flame reaction zone, completing thus the combustion of volatiles, increasing the flame temperature, the heat output from the device, the produced heat energy per mass of burned mixture and decreasing at the same time the mass fraction of unburned volatiles in the products.

  17. Additive mixture effects of estrogenic chemicals in human cell-based assays can be influenced by inclusion of chemicals with differing effect profiles.

    PubMed

    Evans, Richard Mark; Scholze, Martin; Kortenkamp, Andreas

    2012-01-01

    A growing body of experimental evidence indicates that the in vitro effects of mixtures of estrogenic chemicals can be well predicted from the estrogenicity of their components by the concentration addition (CA) concept. However, some studies have observed small deviations from CA. Factors affecting the presence or observation of deviations could include: the type of chemical tested; number of mixture components; mixture design; and assay choice. We designed mixture experiments that address these factors, using mixtures with high numbers of components, chemicals from diverse chemical groups, assays with different in vitro endpoints and different mixture designs and ratios. Firstly, the effects of mixtures composed of up to 17 estrogenic chemicals were examined using estrogenicity assays with reporter-gene (ERLUX) and cell proliferation (ESCREEN) endpoints. Two mixture designs were used: 1) a 'balanced' design with components present in proportion to a common effect concentration (e.g. an EC(10)) and 2) a 'non-balanced' design with components in proportion to potential human tissue concentrations. Secondly, the individual and simultaneous ability of 16 potential modulator chemicals (each with minimal estrogenicity) to influence the assay outcome produced by a reference mixture of estrogenic chemicals was examined. Test chemicals included plasticizers, phthalates, metals, PCBs, phytoestrogens, PAHs, heterocyclic amines, antioxidants, UV filters, musks, PBDEs and parabens. In all the scenarios tested, the CA concept provided a good prediction of mixture effects. Modulation studies revealed that chemicals possessing minimal estrogenicity themselves could reduce (negatively modulate) the effect of a mixture of estrogenic chemicals. Whether the type of modulation we observed occurs in practice most likely depends on the chemical concentrations involved, and better information is required on likely human tissue concentrations of estrogens and of potential modulators

  18. Additive Mixture Effects of Estrogenic Chemicals in Human Cell-Based Assays Can Be Influenced by Inclusion of Chemicals with Differing Effect Profiles

    PubMed Central

    Evans, Richard Mark; Scholze, Martin; Kortenkamp, Andreas

    2012-01-01

    A growing body of experimental evidence indicates that the in vitro effects of mixtures of estrogenic chemicals can be well predicted from the estrogenicity of their components by the concentration addition (CA) concept. However, some studies have observed small deviations from CA. Factors affecting the presence or observation of deviations could include: the type of chemical tested; number of mixture components; mixture design; and assay choice. We designed mixture experiments that address these factors, using mixtures with high numbers of components, chemicals from diverse chemical groups, assays with different in vitro endpoints and different mixture designs and ratios. Firstly, the effects of mixtures composed of up to 17 estrogenic chemicals were examined using estrogenicity assays with reporter-gene (ERLUX) and cell proliferation (ESCREEN) endpoints. Two mixture designs were used: 1) a ‘balanced’ design with components present in proportion to a common effect concentration (e.g. an EC10) and 2) a ‘non-balanced’ design with components in proportion to potential human tissue concentrations. Secondly, the individual and simultaneous ability of 16 potential modulator chemicals (each with minimal estrogenicity) to influence the assay outcome produced by a reference mixture of estrogenic chemicals was examined. Test chemicals included plasticizers, phthalates, metals, PCBs, phytoestrogens, PAHs, heterocyclic amines, antioxidants, UV filters, musks, PBDEs and parabens. In all the scenarios tested, the CA concept provided a good prediction of mixture effects. Modulation studies revealed that chemicals possessing minimal estrogenicity themselves could reduce (negatively modulate) the effect of a mixture of estrogenic chemicals. Whether the type of modulation we observed occurs in practice most likely depends on the chemical concentrations involved, and better information is required on likely human tissue concentrations of estrogens and of potential modulators

  19. A Statistical Approach for Judging Stability of Whole Mixture Chemical Composition over Time for Highly Complex Disinfection By-Product Mixtures from EPA's Four Lab Study

    EPA Science Inventory

    Chemical characterization of complex mixtures and assessment of stability over time of the characterized chemicals is crucial both to characterize exposure and to use data from one mixture as a surrogate for other similar mixtures. The chemical composition of test mixtures can va...

  20. Chemical Mixtures Health Risk Assessment of Environmental Contaminants: Concepts, Methods, And Applications

    EPA Science Inventory

    This problems-based, introductory workshop focuses on methods to assess health risks posed by exposures to chemical mixtures in the environment. Chemical mixtures health risk assessment methods continue to be developed and evolve to address concerns over health risks from multic...

  1. Chemical Mixtures Health Risk Assessment of Environmental Contaminants: Concepts, Methods, Applications: Handbook

    EPA Science Inventory

    This problems-based, half-day, introductory workshop focuses on methods to assess health risks posed by exposures to chemical mixtures in the environment. Chemical mixtures health risk assessment methods continue to be developed and evolve to address concerns over health risks f...

  2. Constituent bioconcentration in rainbow trout exposed to a complex chemical mixture

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Linder, G.; Bergman, H.L.; Meyer, J.S.

    1984-09-01

    Classically, aquatic contaminant fate models predicting a chemical's bioconcentration factor (BCF) are based upon single-compound derived models, yet such BCF predictions may deviate from observed BCFs when physicochemical interactions or biological responses to complex chemical mixture exposures are not adequately considered in the predictive model. Rainbow trout were exposed to oil-shale retort waters. Such a study was designed to model the potential biological effects precluded by exposure to complex chemical mixtures such as solid waste leachates, agricultural runoff, and industrial process waste waters. Chromatographic analysis of aqueous and nonaqueous liquid-liquid reservoir components yielded differences in mixed extraction solvent HPLC profilesmore » of whole fish exposed for 1 and 3 weeks to the highest dilution of the complex chemical mixture when compared to their corresponding control, yet subsequent whole fish extractions at 6, 9, 12, and 15 weeks into exposure demonstrated no qualitative differences between control and exposed fish. Liver extractions and deproteinized bile samples from exposed fish were qualitatively different than their corresponding controls. These findings support the projected NOEC of 0.0045% dilution, even though the differences in bioconcentration profiles suggest hazard assessment strategies may be useful in evaluating environmental fate processes associated with complex chemical mixtures. 12 references, 4 figures, 2 tables.« less

  3. Environmentally relevant chemical mixtures of concern in waters of United States tributaries to the Great Lakes

    USGS Publications Warehouse

    Elliott, Sarah M.; Brigham, Mark E.; Kiesling, Richard L.; Schoenfuss, Heiko L.; Jorgenson, Zachary G.

    2018-01-01

    The North American Great Lakes are a vital natural resource that provide fish and wildlife habitat, as well as drinking water and waste assimilation services for millions of people. Tributaries to the Great Lakes receive chemical inputs from various point and nonpoint sources, and thus are expected to have complex mixtures of chemicals. However, our understanding of the co‐occurrence of specific chemicals in complex mixtures is limited. To better understand the occurrence of specific chemical mixtures in the US Great Lakes Basin, surface water from 24 US tributaries to the Laurentian Great Lakes was collected and analyzed for diverse suites of organic chemicals, primarily focused on chemicals of concern (e.g., pharmaceuticals, personal care products, fragrances). A total of 181 samples and 21 chemical classes were assessed for mixture compositions. Basin wide, 1664 mixtures occurred in at least 25% of sites. The most complex mixtures identified comprised 9 chemical classes and occurred in 58% of sampled tributaries. Pharmaceuticals typically occurred in complex mixtures, reflecting pharmaceutical‐use patterns and wastewater facility outfall influences. Fewer mixtures were identified at lake or lake‐influenced sites than at riverine sites. As mixture complexity increased, the probability of a specific mixture occurring more often than by chance greatly increased, highlighting the importance of understanding source contributions to the environment. This empirically based analysis of mixture composition and occurrence may be used to focus future sampling efforts or mixture toxicity assessments. 

  4. PREDICTING EVAPORATION RATES AND TIMES FOR SPILLS OF CHEMICAL MIXTURES

    EPA Science Inventory


    Spreadsheet and short-cut methods have been developed for predicting evaporation rates and evaporation times for spills (and constrained baths) of chemical mixtures. Steady-state and time-varying predictions of evaporation rates can be made for six-component mixtures, includ...

  5. Aquatic exposures of chemical mixtures in urban environments: Approaches to impact assessment.

    PubMed

    de Zwart, Dick; Adams, William; Galay Burgos, Malyka; Hollender, Juliane; Junghans, Marion; Merrington, Graham; Muir, Derek; Parkerton, Thomas; De Schamphelaere, Karel A C; Whale, Graham; Williams, Richard

    2018-03-01

    Urban regions of the world are expanding rapidly, placing additional stress on water resources. Urban water bodies serve many purposes, from washing and sources of drinking water to transport and conduits for storm drainage and effluent discharge. These water bodies receive chemical emissions arising from either single or multiple point sources, diffuse sources which can be continuous, intermittent, or seasonal. Thus, aquatic organisms in these water bodies are exposed to temporally and compositionally variable mixtures. We have delineated source-specific signatures of these mixtures for diffuse urban runoff and urban point source exposure scenarios to support risk assessment and management of these mixtures. The first step in a tiered approach to assessing chemical exposure has been developed based on the event mean concentration concept, with chemical concentrations in runoff defined by volumes of water leaving each surface and the chemical exposure mixture profiles for different urban scenarios. Although generalizations can be made about the chemical composition of urban sources and event mean exposure predictions for initial prioritization, such modeling needs to be complemented with biological monitoring data. It is highly unlikely that the current paradigm of routine regulatory chemical monitoring alone will provide a realistic appraisal of urban aquatic chemical mixture exposures. Future consideration is also needed of the role of nonchemical stressors in such highly modified urban water bodies. Environ Toxicol Chem 2018;37:703-714. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

  6. Overview of human health and chemical mixtures: problems facing developing countries.

    PubMed

    Yáñ ez, Leticia; Ortiz, Deogracias; Calderón, Jaqueline; Batres, Lilia; Carrizales, Leticia; Mejía, Jesús; Martínez, Lourdes; García-Nieto, Edelmira; Díaz-Barriga, Fernando

    2002-12-01

    In developing countries, chemical mixtures within the vicinity of small-scale enterprises, smelters, mines, agricultural areas, toxic waste disposal sites, etc., often present a health hazard to the populations within those vicinities. Therefore, in these countries, there is a need to study the toxicological effects of mixtures of metals, pesticides, and organic compounds. However, the study of mixtures containing substances such as DDT (dichlorodiphenyltrichloroethane, an insecticide banned in developed nations), and mixtures containing contaminants such as fluoride (of concern only in developing countries) merit special attention. Although the studies may have to take into account simultaneous exposures to metals and organic compounds, there is also a need to consider the interaction between chemicals and other specific factors such as nutritional conditions, alcoholism, smoking, infectious diseases, and ethnicity.

  7. Cumulative effects of antiandrogenic chemical mixtures and their relevance to human health risk assessment

    EPA Science Inventory

    Toxicological studies of defined chemical mixtures assist human health risk assessment by establishing the manner by which chemicals interact with one another to induce an effect. This paper reviews how antiandrogenic chemical mixtures can alter reproductive tract development in ...

  8. Thermal Conductivity of Gas Mixtures in Chemical Equilibrium

    NASA Technical Reports Server (NTRS)

    Brokaw, Richard S.

    1960-01-01

    The expression for the thermal conductivity of gas mixtures in chemical equilibrium is presented in a simpler and less restrictive form. This new form is shown to be equivalent to the previous equations.

  9. Identification and Prioritization of Chemical Mixtures from Environmental Residue Data

    EPA Science Inventory

    High throughput toxicity testing has greatly improved the speed at which single chemicals can be screened using in vitro methods. However, people are not exposed to a single chemical at a time, rather to a mixture of chemicals. Even with the increased speed of these methods, te...

  10. Overview of human health and chemical mixtures: problems facing developing countries.

    PubMed Central

    Yáñ ez, Leticia; Ortiz, Deogracias; Calderón, Jaqueline; Batres, Lilia; Carrizales, Leticia; Mejía, Jesús; Martínez, Lourdes; García-Nieto, Edelmira; Díaz-Barriga, Fernando

    2002-01-01

    In developing countries, chemical mixtures within the vicinity of small-scale enterprises, smelters, mines, agricultural areas, toxic waste disposal sites, etc., often present a health hazard to the populations within those vicinities. Therefore, in these countries, there is a need to study the toxicological effects of mixtures of metals, pesticides, and organic compounds. However, the study of mixtures containing substances such as DDT (dichlorodiphenyltrichloroethane, an insecticide banned in developed nations), and mixtures containing contaminants such as fluoride (of concern only in developing countries) merit special attention. Although the studies may have to take into account simultaneous exposures to metals and organic compounds, there is also a need to consider the interaction between chemicals and other specific factors such as nutritional conditions, alcoholism, smoking, infectious diseases, and ethnicity. PMID:12634117

  11. Automatic NMR-Based Identification of Chemical Reaction Types in Mixtures of Co-Occurring Reactions

    PubMed Central

    Latino, Diogo A. R. S.; Aires-de-Sousa, João

    2014-01-01

    The combination of chemoinformatics approaches with NMR techniques and the increasing availability of data allow the resolution of problems far beyond the original application of NMR in structure elucidation/verification. The diversity of applications can range from process monitoring, metabolic profiling, authentication of products, to quality control. An application related to the automatic analysis of complex mixtures concerns mixtures of chemical reactions. We encoded mixtures of chemical reactions with the difference between the 1H NMR spectra of the products and the reactants. All the signals arising from all the reactants of the co-occurring reactions were taken together (a simulated spectrum of the mixture of reactants) and the same was done for products. The difference spectrum is taken as the representation of the mixture of chemical reactions. A data set of 181 chemical reactions was used, each reaction manually assigned to one of 6 types. From this dataset, we simulated mixtures where two reactions of different types would occur simultaneously. Automatic learning methods were trained to classify the reactions occurring in a mixture from the 1H NMR-based descriptor of the mixture. Unsupervised learning methods (self-organizing maps) produced a reasonable clustering of the mixtures by reaction type, and allowed the correct classification of 80% and 63% of the mixtures in two independent test sets of different similarity to the training set. With random forests (RF), the percentage of correct classifications was increased to 99% and 80% for the same test sets. The RF probability associated to the predictions yielded a robust indication of their reliability. This study demonstrates the possibility of applying machine learning methods to automatically identify types of co-occurring chemical reactions from NMR data. Using no explicit structural information about the reactions participants, reaction elucidation is performed without structure elucidation of the

  12. Automatic NMR-based identification of chemical reaction types in mixtures of co-occurring reactions.

    PubMed

    Latino, Diogo A R S; Aires-de-Sousa, João

    2014-01-01

    The combination of chemoinformatics approaches with NMR techniques and the increasing availability of data allow the resolution of problems far beyond the original application of NMR in structure elucidation/verification. The diversity of applications can range from process monitoring, metabolic profiling, authentication of products, to quality control. An application related to the automatic analysis of complex mixtures concerns mixtures of chemical reactions. We encoded mixtures of chemical reactions with the difference between the (1)H NMR spectra of the products and the reactants. All the signals arising from all the reactants of the co-occurring reactions were taken together (a simulated spectrum of the mixture of reactants) and the same was done for products. The difference spectrum is taken as the representation of the mixture of chemical reactions. A data set of 181 chemical reactions was used, each reaction manually assigned to one of 6 types. From this dataset, we simulated mixtures where two reactions of different types would occur simultaneously. Automatic learning methods were trained to classify the reactions occurring in a mixture from the (1)H NMR-based descriptor of the mixture. Unsupervised learning methods (self-organizing maps) produced a reasonable clustering of the mixtures by reaction type, and allowed the correct classification of 80% and 63% of the mixtures in two independent test sets of different similarity to the training set. With random forests (RF), the percentage of correct classifications was increased to 99% and 80% for the same test sets. The RF probability associated to the predictions yielded a robust indication of their reliability. This study demonstrates the possibility of applying machine learning methods to automatically identify types of co-occurring chemical reactions from NMR data. Using no explicit structural information about the reactions participants, reaction elucidation is performed without structure elucidation of

  13. A FLEXIBLE APPROACH FOR EVALUATING FIXED RATIO MIXTURES OF FULL AND PARTIAL AGONISTS FOR MIXTURES OF MANY CHEMICALS.

    EPA Science Inventory

    Detecting interaction in chemical mixtures can be complicated by differences in the shapes of the dose-response curves of the individual components (e.g. mixtures of full and partial agonists with differing response maxima). We present an analysis scheme where flexible single che...

  14. COMPLEX MIXTURES OF CHEMICAL CARCINOGENS: PRINCIPLES OF ACTION AND HUMAN CANCER

    EPA Science Inventory

    There is strong epidemiological evidence supported by experimental animal data that complex environmental mixtures pose a risk to human health producing increases in cancer incidence. Understanding the chemical and biological properties of these mixtures leads to a clearer unde...

  15. Transferring mixtures of chemicals from sediment to a bioassay using silicone-based passive sampling and dosing.

    PubMed

    Mustajärvi, Lukas; Eriksson-Wiklund, Ann-Kristin; Gorokhova, Elena; Jahnke, Annika; Sobek, Anna

    2017-11-15

    Environmental mixtures of chemicals consist of a countless number of compounds with unknown identity and quantity. Yet, chemical regulation is mainly built around the assessment of single chemicals. Existing frameworks for assessing the toxicity of mixtures require that both the chemical composition and quantity are known. Quantitative analyses of the chemical composition of environmental mixtures are however extremely challenging and resource-demanding. Bioassays may therefore serve as a useful approach for investigating the combined toxicity of environmental mixtures of chemicals in a cost-efficient and holistic manner. In this study, an unknown environmental mixture of bioavailable semi-hydrophobic to hydrophobic chemicals was sampled from a contaminated sediment in a coastal Baltic Sea area using silicone polydimethylsiloxane (PDMS) as an equilibrium passive sampler. The chemical mixture was transferred to a PDMS-based passive dosing system, and its applicability was demonstrated using green algae Tetraselmis suecica in a cell viability assay. The proportion of dead cells increased significantly with increasing exposure level and in a dose-response manner. At an ambient concentration, the proportion of dead cells in the population was nearly doubled compared to the control; however, the difference was non-significant due to high inter-replicate variability and a low number of replicates. The validation of the test system regarding equilibrium sampling, loading efficiency into the passive dosing polymer, stability of the mixture composition, and low algal mortality in control treatments demonstrates that combining equilibrium passive sampling and passive dosing is a promising tool for investigating the toxicity of bioavailable semi-hydrophobic and hydrophobic chemicals in complex environmental mixtures.

  16. Cumulative effects of anti-androgenic chemical mixtures and their relevance to human health risk assessment

    EPA Science Inventory

    Kembra L. Howdeshell and L. Earl Gray, Jr.Toxicological studies of defined chemical mixtures assist human health risk assessment by characterizing the joint action of chemicals. This presentation will review the effects of anti-androgenic chemical mixtures on reproductive tract d...

  17. 40 CFR 68.125 - Exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Exemptions. 68.125 Section 68.125 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CHEMICAL ACCIDENT PREVENTION PROVISIONS Regulated Substances for Accidental Release Prevention § 68.125 Exemptions...

  18. Chemical mixtures: Evaluation of risk for child-specific exposures in a multi-stressor environment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pohl, H.R.; Abadin, H.G.

    Evaluating the health impact from exposure to chemical mixtures is multifaceted. One component is exposure. Exposure, and consequently risk assessment for mixtures and chemicals in general, are often viewed in terms of a given exposure to a given population at a given location over a given time period. However, environmental exposures are present throughout human lifetime. As a result, an evaluation of risk must include the distinctive characteristics related to chemical exposures which will impact risk depending upon the particular life stage where exposure occurs. Risks to offspring may be associated with unique exposures in utero, during infancy, childhood, ormore » adolescent periods. For example, exposure of infants to anthropogenic chemicals via breast milk may be of concern. The Agency for Toxic Substances and Disease Registry's (ATSDR's) approach to evaluating risks associated with exposure to mixtures of chemicals is presented. In addition to the breast milk issues, indoor exposure to combined air pollutants, drinking water contaminants, and soil and dust contaminants are discussed. The difference between a mixture's risk evaluation for children and adults is in the distinct exposure scenarios resulting from variations in behavior, physiology, and/or pharmacokinetics between adults and children rather than in the method for the specific mixtures evaluation per se.« less

  19. Initial analyses of the relationship between 'Thresholds' of toxicity for individual chemicals and 'Interaction Thresholds' for chemical mixtures

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yang, Raymond S.H.; Dennison, James E.

    2007-09-01

    The inter-relationship of 'Thresholds' between chemical mixtures and their respective component single chemicals was studied using three sets of data and two types of analyses. Two in vitro data sets involve cytotoxicity in human keratinocytes from treatment of metals and a metal mixture [Bae, D.S., Gennings, C., Carter, Jr., W.H., Yang, R.S.H., Campain, J.A., 2001. Toxicological interactions among arsenic, cadmium, chromium, and lead in human keratinocytes. Toxicol. Sci. 63, 132-142; Gennings, C., Carter, Jr., W.H., Campain, J.A., Bae, D.S., Yang, R.S.H., 2002. Statistical analysis of interactive cytotoxicity in human epidermal keratinocytes following exposure to a mixture of four metals. J.more » Agric. Biol. Environ. Stat. 7, 58-73], and induction of estrogen receptor alpha (ER-{alpha}) reporter gene in MCF-7 human breast cancer cells by estrogenic xenobiotics [Gennings, C., Carter, Jr., W.H., Carney, E.W., Charles, G.D., Gollapudi, B.B., Carchman, R.A., 2004. A novel flexible approach for evaluating fixed ratio mixtures of full and partial agonists. Toxicol. Sci. 80, 134-150]. The third data set came from PBPK modeling of gasoline and its components in the human. For in vitro cellular responses, we employed Benchmark Dose Software (BMDS) to obtain BMD{sub 01}, BMD{sub 05}, and BMD{sub 10}. We then plotted these BMDs against exposure concentrations for the chemical mixture and its components to assess the ranges and slopes of these BMD-concentration lines. In doing so, we consider certain BMDs to be 'Interaction Thresholds' or 'Thresholds' for mixtures and their component single chemicals and the slope of the line must be a reflection of the potency of the biological effects. For in vivo PBPK modeling, we used 0.1x TLVs, TLVs, and 10x TLVs for gasoline and six component markers as input dosing for PBPK modeling. In this case, the venous blood levels under the hypothetical exposure conditions become our designated 'Interaction Thresholds' or 'Thresholds' for

  20. Considering the cumulative risk of mixtures of chemicals – A challenge for policy makers

    PubMed Central

    2012-01-01

    Background The current paradigm for the assessment of the health risk of chemical substances focuses primarily on the effects of individual substances for determining the doses of toxicological concern in order to inform appropriately the regulatory process. These policy instruments place varying requirements on health and safety data of chemicals in the environment. REACH focuses on safety of individual substances; yet all the other facets of public health policy that relate to chemical stressors put emphasis on the effects of combined exposure to mixtures of chemical and physical agents. This emphasis brings about methodological problems linked to the complexity of the respective exposure pathways; the effect (more complex than simple additivity) of mixtures (the so-called 'cocktail effect'); dose extrapolation, i.e. the extrapolation of the validity of dose-response data to dose ranges that extend beyond the levels used for the derivation of the original dose-response relationship; the integrated use of toxicity data across species (including human clinical, epidemiological and biomonitoring data); and variation in inter-individual susceptibility associated with both genetic and environmental factors. Methods In this paper we give an overview of the main methodologies available today to estimate the human health risk of environmental chemical mixtures, ranging from dose addition to independent action, and from ignoring interactions among the mixture constituents to modelling their biological fate taking into account the biochemical interactions affecting both internal exposure and the toxic potency of the mixture. Results We discuss their applicability, possible options available to policy makers and the difficulties and potential pitfalls in implementing these methodologies in the frame of the currently existing policy framework in the European Union. Finally, we suggest a pragmatic solution for policy/regulatory action that would facilitate the evaluation of

  1. Regulatory assessment of chemical mixtures: Requirements, current approaches and future perspectives.

    PubMed

    Kienzler, Aude; Bopp, Stephanie K; van der Linden, Sander; Berggren, Elisabet; Worth, Andrew

    2016-10-01

    This paper reviews regulatory requirements and recent case studies to illustrate how the risk assessment (RA) of chemical mixtures is conducted, considering both the effects on human health and on the environment. A broad range of chemicals, regulations and RA methodologies are covered, in order to identify mixtures of concern, gaps in the regulatory framework, data needs, and further work to be carried out. Also the current and potential future use of novel tools (Adverse Outcome Pathways, in silico tools, toxicokinetic modelling, etc.) in the RA of combined effects were reviewed. The assumptions made in the RA, predictive model specifications and the choice of toxic reference values can greatly influence the assessment outcome, and should therefore be specifically justified. Novel tools could support mixture RA mainly by providing a better understanding of the underlying mechanisms of combined effects. Nevertheless, their use is currently limited because of a lack of guidance, data, and expertise. More guidance is needed to facilitate their application. As far as the authors are aware, no prospective RA concerning chemicals related to various regulatory sectors has been performed to date, even though numerous chemicals are registered under several regulatory frameworks. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  2. 30 CFR 47.92 - Exemptions from labeling.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... COMMUNICATION (HazCom) Exemptions § 47.92 Exemptions from labeling. A hazardous chemical is exempt from subpart E of this part under the conditions described in Table 47.92 as follows: Table 47.92—Hazardous... accordance with EPA regulations. Hazardous waste When regulated by EPA under the Solid Waste Disposal Act as...

  3. NEUROBEHAVIORAL EVALUATIONS OF BINARY AND TERTIARY MIXTURES OF CHEMICALS: LESSIONS LEARNING.

    EPA Science Inventory

    The classical approach to the statistical analysis of binary chemical mixtures is to construct full dose-response curves for one compound in the presence of a range of doses of the second compound (isobolographic analyses). For interaction studies using more than two chemicals, ...

  4. Chemical mixtures in untreated water from public-supply wells in the U.S. — Occurrence, composition, and potential toxicity

    USGS Publications Warehouse

    Toccalino, Patricia L.; Norman, Julia E.; Scott, Jonathon C.

    2012-01-01

    Chemical mixtures are prevalent in groundwater used for public water supply, but little is known about their potential health effects. As part of a large-scale ambient groundwater study, we evaluated chemical mixtures across multiple chemical classes, and included more chemical contaminants than in previous studies of mixtures in public-supply wells. We (1) assessed the occurrence of chemical mixtures in untreated source-water samples from public-supply wells, (2) determined the composition of the most frequently occurring mixtures, and (3) characterized the potential toxicity of mixtures using a new screening approach. The U.S. Geological Survey collected one untreated water sample from each of 383 public wells distributed across 35 states, and analyzed the samples for as many as 91 chemical contaminants. Concentrations of mixture components were compared to individual human-health benchmarks; the potential toxicity of mixtures was characterized by addition of benchmark-normalized component concentrations. Most samples (84%) contained mixtures of two or more contaminants, each at concentrations greater than one-tenth of individual benchmarks. The chemical mixtures that most frequently occurred and had the greatest potential toxicity primarily were composed of trace elements (including arsenic, strontium, or uranium), radon, or nitrate. Herbicides, disinfection by-products, and solvents were the most common organic contaminants in mixtures. The sum of benchmark-normalized concentrations was greater than 1 for 58% of samples, suggesting that there could be potential for mixtures toxicity in more than half of the public-well samples. Our findings can be used to help set priorities for groundwater monitoring and suggest future research directions for drinking-water treatment studies and for toxicity assessments of chemical mixtures in water resources.

  5. 40 CFR 720.38 - Exemptions for test marketing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Exemptions for test marketing. 720.38... CONTROL ACT PREMANUFACTURE NOTIFICATION Applicability § 720.38 Exemptions for test marketing. (a) Any person may apply for an exemption to manufacture or import a new chemical substance for test marketing...

  6. 40 CFR 720.38 - Exemptions for test marketing.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Exemptions for test marketing. 720.38... CONTROL ACT PREMANUFACTURE NOTIFICATION Applicability § 720.38 Exemptions for test marketing. (a) Any person may apply for an exemption to manufacture or import a new chemical substance for test marketing...

  7. 40 CFR 720.38 - Exemptions for test marketing.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Exemptions for test marketing. 720.38... CONTROL ACT PREMANUFACTURE NOTIFICATION Applicability § 720.38 Exemptions for test marketing. (a) Any person may apply for an exemption to manufacture or import a new chemical substance for test marketing...

  8. 40 CFR 720.38 - Exemptions for test marketing.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Exemptions for test marketing. 720.38... CONTROL ACT PREMANUFACTURE NOTIFICATION Applicability § 720.38 Exemptions for test marketing. (a) Any person may apply for an exemption to manufacture or import a new chemical substance for test marketing...

  9. Polymer Exemption for New Chemicals under the Toxic Substances Control Act (TSCA)

    EPA Pesticide Factsheets

    EPA has established an exemption for certain polymers to encourage manufacturers to make safer polymers. To learn more about this exemption, eligibility, and it's requirements, read this overview of the exemption.

  10. Chemical recognition of gases and gas mixtures with terahertz waves.

    PubMed

    Jacobsen, R H; Mittleman, D M; Nuss, M C

    1996-12-15

    A time-domain chemical-recognition system for classifying gases and analyzing gas mixtures is presented. We analyze the free induction decay exhibited by gases excited by far-infrared (terahertz) pulses in the time domain, using digital signal-processing techniques. A simple geometric picture is used for the classif ication of the waveforms measured for unknown gas species. We demonstrate how the recognition system can be used to determine the partial pressures of an ammonia-water gas mixture.

  11. Chemical recognition of gases and gas mixtures with terahertz waves

    NASA Astrophysics Data System (ADS)

    Jacobsen, R. H.; Mittleman, D. M.; Nuss, M. C.

    1996-12-01

    A time-domain chemical-recognition system for classifying gases and analyzing gas mixtures is presented. We analyze the free induction decay exhibited by gases excited by far-infrared (terahertz) pulses in the time domain, using digital signal-processing techniques. A simple geometric picture is used for the classification of the waveforms measured for unknown gas species. We demonstrate how the recognition system can be used to determine the partial pressures of an ammonia-water gas mixture.

  12. 40 CFR 180.900 - Exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From... granted when it appears that the total quantity of the pesticide chemical in or on all raw agricultural...

  13. 40 CFR 180.900 - Exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From... granted when it appears that the total quantity of the pesticide chemical in or on all raw agricultural...

  14. Separation of mixtures of chemical elements in plasma

    NASA Astrophysics Data System (ADS)

    Dolgolenko, D. A.; Muromkin, Yu A.

    2017-10-01

    This paper reviews proposals on the plasma processing of radioactive waste (RW) and spent nuclear fuel (SNF). The chemical processing of SNF based on the extraction of its components from water solutions is rather expensive and produces new waste. The paper considers experimental research on plasma separation of mixtures of chemical elements and isotopes, whose results can help evaluate the plasma methods of RW and SNF reprocessing. The analysis identifies the difference between ionization levels of RW and SNF components at their transition to the plasma phase as a reason why all plasma methods are difficult to apply.

  15. Effect of a chemical mixture on dermal penetration of arsenic and nickel in male pig in vitro.

    PubMed

    Turkall, Rita M; Skowronski, Gloria A; Suh, Duck H; Abdel-Rahman, Mohamed S

    2003-04-11

    The effect of a chemical mixture on the dermal penetration of arsenic or nickel was assessed by applying arsenic-73 or nickel-63 alone or with the chemical mixture to dermatomed male pig skin samples in flow-through diffusion cells. The chemical mixture consisted of chloroform, phenanthrene, and toluene for arsenic penetration studies and phenol, toluene, and trichloroethylene (TCE) for nickel studies. These are predominant chemicals found at hazardous waste sites. Arsenic and nickel bind to skin after dermal exposure. Total penetration of arsenic and nickel in the chemical mixture were significantly increased by 33% and 20% compared to arsenic and nickel alone, respectively. While more radioactivity penetrated skin with chemical treatment than metal alone, significantly less radioactivity was loosely adsorbed to skin and could be easily washed off from the skin surface with soap and water. The results of this study indicate that the potential health risk from dermal exposure to arsenic or nickel is enhanced if other chemicals are present.

  16. Biogeographical Analysis of Chemical Co-Occurrence Data to Identify Priorities for Mixtures Research

    EPA Science Inventory

    A challenge with multiple chemical risk assessment is the need to consider the joint behavior of chemicals in mixtures. To address this need, pharmacologists and toxicologists have developed methods over the years to evaluate and test chemical interaction. In practice, however, t...

  17. 40 CFR 180.1057 - Phytophthora palmivora; exemption from requirement of tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions.... Phytophthora palmivora is exempted from the requirement of a tolerance in or on the raw agricultural commodity...

  18. 40 CFR 180.1057 - Phytophthora palmivora; exemption from requirement of tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions.... Phytophthora palmivora is exempted from the requirement of a tolerance in or on the raw agricultural commodity...

  19. Reacting gas mixtures in the state-to-state approach: The chemical reaction rates

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kustova, Elena V.; Kremer, Gilberto M.

    2014-12-09

    In this work chemically reacting mixtures of viscous flows are analyzed within the framework of Boltzmann equation. By applying a modified Chapman-Enskog method to the system of Boltzmann equations general expressions for the rates of chemical reactions and vibrational energy transitions are determined as functions of two thermodynamic forces: the velocity divergence and the affinity. As an application chemically reacting mixtures of N{sub 2} across a shock wave are studied, where the first lowest vibrational states are taken into account. Here we consider only the contributions from the first four single quantum vibrational-translational energy transitions. It is shown that themore » contribution to the chemical reaction rate related to the affinity is much larger than that of the velocity divergence.« less

  20. 7 CFR 1205.519 - Organic exemption.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... for organic products, isolated use of antibiotics for humane purposes, chemical or pesticide use as... 7 Agriculture 10 2013-01-01 2013-01-01 false Organic exemption. 1205.519 Section 1205.519... Cotton Board Rules and Regulations Assessments § 1205.519 Organic exemption. (a) A producer who operates...

  1. 7 CFR 1205.519 - Organic exemption.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... for organic products, isolated use of antibiotics for humane purposes, chemical or pesticide use as... 7 Agriculture 10 2012-01-01 2012-01-01 false Organic exemption. 1205.519 Section 1205.519... Cotton Board Rules and Regulations Assessments § 1205.519 Organic exemption. (a) A producer who operates...

  2. 7 CFR 1205.519 - Organic exemption.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... for organic products, isolated use of antibiotics for humane purposes, chemical or pesticide use as... 7 Agriculture 10 2014-01-01 2014-01-01 false Organic exemption. 1205.519 Section 1205.519... Cotton Board Rules and Regulations Assessments § 1205.519 Organic exemption. (a) A producer who operates...

  3. Comparison of Chemical Composition of Complex Disinfection Byproduct (DBP) Mixtures Produced by Different Treatment Methods

    EPA Science Inventory

    Analyses of the chemical composition of complex DBP mixtures, produced by different drinking water treatment processes, are essential to generate toxicity data required for assessing their risks to humans. For mixture risk assessments, whole mixture toxicology studies generally a...

  4. 30 CFR 47.91 - Exemptions from the HazCom standard.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Exemptions from the HazCom standard. 47.91... TRAINING HAZARD COMMUNICATION (HazCom) Exemptions § 47.91 Exemptions from the HazCom standard. A hazardous chemical is exempt from this part under the conditions described in Table 47.91 as follows: Table 47.91...

  5. Environmental chemical mixtures: Assessing ecological exposure and effects in streams

    EPA Science Inventory

    This product is a USGS fact sheet that describes a collaborative effort between USGS and US EPA to characterize exposures to chemical mixtures and associated biological effects for a diverse range of US streams representing varying watershed size, land-use patterns, and ecotypes.

  6. Environmental mixtures of nanomaterials and chemicals: The Trojan-horse phenomenon and its relevance for ecotoxicity.

    PubMed

    Naasz, Steffi; Altenburger, Rolf; Kühnel, Dana

    2018-04-22

    The usage of engineered nanomaterials (NM) offers many novel products and applications with advanced features, but at the same time raises concerns with regard to potential adverse biological effects. Upon release and emission, NM may interact with chemicals in the environment, potentially leading to a co-exposure of organisms and the occurrence of mixture effects. A prominent idea is that NM may act as carriers of chemicals, facilitating and enhancing the entry of substances into cells or organisms, subsequently leading to an increased toxicity. In the literature, the term 'Trojan-horse effect' describes this hypothesis. The relevance of this mechanism for organisms is, however, unclear as yet. Here, a review has been performed to provide a more systematic picture on existing evidence. It includes 151 experimental studies investigating the exposure of various NM and chemical mixtures in ecotoxicological in vitro and in vivo model systems. The papers retrieved comprised studies investigating (i) uptake, (ii) toxicity and (iii) investigations considering both, changes in substance uptake and toxicity upon joint exposure of a chemical with an NM. A closer inspection of the studies demonstrated that the existing evidence for interference of NM-chemical mixture exposure with uptake and toxicity points into different directions compared to the original Trojan-horse hypothesis. We could discriminate at least 7 different categories to capture the evidence ranging from no changes in uptake and toxicity to an increase in uptake and toxicity upon mixture exposure. Concluding recommendations for the consideration of relevant processes are given, including a proposal for a nomenclature to describe NM-chemical mixture interactions in consistent terms. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  7. Analysis of Environmental Chemical Mixtures and Non-Hodgkin Lymphoma Risk in the NCI-SEER NHL Study.

    PubMed

    Czarnota, Jenna; Gennings, Chris; Colt, Joanne S; De Roos, Anneclaire J; Cerhan, James R; Severson, Richard K; Hartge, Patricia; Ward, Mary H; Wheeler, David C

    2015-10-01

    There are several suspected environmental risk factors for non-Hodgkin lymphoma (NHL). The associations between NHL and environmental chemical exposures have typically been evaluated for individual chemicals (i.e., one-by-one). We determined the association between a mixture of 27 correlated chemicals measured in house dust and NHL risk. We conducted a population-based case-control study of NHL in four National Cancer Institute-Surveillance, Epidemiology, and End Results centers--Detroit, Michigan; Iowa; Los Angeles County, California; and Seattle, Washington--from 1998 to 2000. We used weighted quantile sum (WQS) regression to model the association of a mixture of chemicals and risk of NHL. The WQS index was a sum of weighted quartiles for 5 polychlorinated biphenyls (PCBs), 7 polycyclic aromatic hydrocarbons (PAHs), and 15 pesticides. We estimated chemical mixture weights and effects for study sites combined and for each site individually, and also for histologic subtypes of NHL. The WQS index was statistically significantly associated with NHL overall [odds ratio (OR) = 1.30; 95% CI: 1.08, 1.56; p = 0.006; for one quartile increase] and in the study sites of Detroit (OR = 1.71; 95% CI: 1.02, 2.92; p = 0.045), Los Angeles (OR = 1.44; 95% CI: 1.00, 2.08; p = 0.049), and Iowa (OR = 1.76; 95% CI: 1.23, 2.53; p = 0.002). The index was marginally statistically significant in Seattle (OR = 1.39; 95% CI: 0.97, 1.99; p = 0.071). The most highly weighted chemicals for predicting risk overall were PCB congener 180 and propoxur. Highly weighted chemicals varied by study site; PCBs were more highly weighted in Detroit, and pesticides were more highly weighted in Iowa. An index of chemical mixtures was significantly associated with NHL. Our results show the importance of evaluating chemical mixtures when studying cancer risk.

  8. Mixtures of Chemical Pollutants at European Legislation Safety Concentrations: How Safe Are They?

    PubMed Central

    Carvalho, Raquel N.; Arukwe, Augustine; Ait-Aissa, Selim; Bado-Nilles, Anne; Balzamo, Stefania; Baun, Anders; Belkin, Shimshon; Blaha, Ludek; Brion, François; Conti, Daniela; Creusot, Nicolas; Essig, Yona; Ferrero, Valentina E. V.; Flander-Putrle, Vesna; Fürhacker, Maria; Grillari-Voglauer, Regina; Hogstrand, Christer; Jonáš, Adam; Kharlyngdoh, Joubert B.; Loos, Robert; Lundebye, Anne-Katrine; Modig, Carina; Olsson, Per-Erik; Pillai, Smitha; Polak, Natasa; Potalivo, Monica; Sanchez, Wilfried; Schifferli, Andrea; Schirmer, Kristin; Sforzini, Susanna; Stürzenbaum, Stephen R.; Søfteland, Liv; Turk, Valentina; Viarengo, Aldo; Werner, Inge; Yagur-Kroll, Sharon; Zounková, Radka; Lettieri, Teresa

    2014-01-01

    The risk posed by complex chemical mixtures in the environment to wildlife and humans is increasingly debated, but has been rarely tested under environmentally relevant scenarios. To address this issue, two mixtures of 14 or 19 substances of concern (pesticides, pharmaceuticals, heavy metals, polyaromatic hydrocarbons, a surfactant, and a plasticizer), each present at its safety limit concentration imposed by the European legislation, were prepared and tested for their toxic effects. The effects of the mixtures were assessed in 35 bioassays, based on 11 organisms representing different trophic levels. A consortium of 16 laboratories was involved in performing the bioassays. The mixtures elicited quantifiable toxic effects on some of the test systems employed, including i) changes in marine microbial composition, ii) microalgae toxicity, iii) immobilization in the crustacean Daphnia magna, iv) fish embryo toxicity, v) impaired frog embryo development, and vi) increased expression on oxidative stress-linked reporter genes. Estrogenic activity close to regulatory safety limit concentrations was uncovered by receptor-binding assays. The results highlight the need of precautionary actions on the assessment of chemical mixtures even in cases where individual toxicants are present at seemingly harmless concentrations. PMID:24958932

  9. Analysis of Environmental Chemical Mixtures and Non-Hodgkin Lymphoma Risk in the NCI-SEER NHL Study

    PubMed Central

    Czarnota, Jenna; Gennings, Chris; Colt, Joanne S.; De Roos, Anneclaire J.; Cerhan, James R.; Severson, Richard K.; Hartge, Patricia; Ward, Mary H.

    2015-01-01

    Background There are several suspected environmental risk factors for non-Hodgkin lymphoma (NHL). The associations between NHL and environmental chemical exposures have typically been evaluated for individual chemicals (i.e., one-by-one). Objectives We determined the association between a mixture of 27 correlated chemicals measured in house dust and NHL risk. Methods We conducted a population-based case–control study of NHL in four National Cancer Institute–Surveillance, Epidemiology, and End Results centers—Detroit, Michigan; Iowa; Los Angeles County, California; and Seattle, Washington—from 1998 to 2000. We used weighted quantile sum (WQS) regression to model the association of a mixture of chemicals and risk of NHL. The WQS index was a sum of weighted quartiles for 5 polychlorinated biphenyls (PCBs), 7 polycyclic aromatic hydrocarbons (PAHs), and 15 pesticides. We estimated chemical mixture weights and effects for study sites combined and for each site individually, and also for histologic subtypes of NHL. Results The WQS index was statistically significantly associated with NHL overall [odds ratio (OR) = 1.30; 95% CI: 1.08, 1.56; p = 0.006; for one quartile increase] and in the study sites of Detroit (OR = 1.71; 95% CI: 1.02, 2.92; p = 0.045), Los Angeles (OR = 1.44; 95% CI: 1.00, 2.08; p = 0.049), and Iowa (OR = 1.76; 95% CI: 1.23, 2.53; p = 0.002). The index was marginally statistically significant in Seattle (OR = 1.39; 95% CI: 0.97, 1.99; p = 0.071). The most highly weighted chemicals for predicting risk overall were PCB congener 180 and propoxur. Highly weighted chemicals varied by study site; PCBs were more highly weighted in Detroit, and pesticides were more highly weighted in Iowa. Conclusions An index of chemical mixtures was significantly associated with NHL. Our results show the importance of evaluating chemical mixtures when studying cancer risk. Citation Czarnota J, Gennings C, Colt JS, De Roos AJ, Cerhan JR, Severson RK, Hartge P, Ward MH

  10. 15 CFR 30.37 - Miscellaneous exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... of Electronic Export Information § 30.37 Miscellaneous exemptions. Filing EEI is not required for the...), exports of commodities where the value of the commodities shipped from one USPPI to one consignee on a... classification codes regardless of the total shipment value. In instances where a shipment contains a mixture of...

  11. Perinatal exposure to mixtures of anti-androgenic chemicals causes proliferative lesions in rat prostate.

    PubMed

    Boberg, Julie; Johansson, Hanna K L; Hadrup, Niels; Dreisig, Karin; Berthelsen, Line; Almstrup, Kristian; Vinggaard, Anne Marie; Hass, Ulla

    2015-02-01

    Elevated levels of endogenous or exogenous estrogens during fetal life can induce permanent disturbances in prostate growth and predispose to precancerous lesions. Recent studies have indicated that also early anti-androgen exposure may affect prostate cancer risk. We examined the influence of perinatal exposure to mixtures of anti-androgenic and estrogenic chemicals on prostate development. Wistar rats were exposed from gestation day 7 to postnatal day 22 to a mixture of 8 anti-androgenic compounds (AAMix), a mixture of four estrogenic compounds (EMix), or paracetamol or a mixture of all 13 compounds (TotalMix) in mixture ratios reflecting human exposure levels. Ventral prostate weights were reduced by the TotalMix and AAMix in pre-pubertal rats. Histological changes in prostate appeared with increasing age and indicated a shift from the normal age-dependent epithelial atrophy towards hyperplasia. These lesions showed similarities to pre-cancerous lesions in humans. Increased proliferation was observed already in pre-puberty and it was hypothesized that this could be associated with reduced ERβ signaling, but no clear conclusions could be made from gene expression studies on ERβ-related pathways. The influences of the estrogenic chemicals and paracetamol on prostate morphology were minor, but in young adulthood the estrogen mixture reduced ventral prostate mRNA levels of Igf1 and paracetamol reduced the mRNA level ofPbpc3. Mixtures of endocrine disrupters relevant for human exposure was found to elicit persistent effects on the rat prostate following perinatal exposure, suggesting that human perinatal exposure to environmental chemicals may increase the risk of prostate cancer later in life. © 2014 Wiley Periodicals, Inc.

  12. Hierarchical Bayesian Approach To Reduce Uncertainty in the Aquatic Effect Assessment of Realistic Chemical Mixtures.

    PubMed

    Oldenkamp, Rik; Hendriks, Harrie W M; van de Meent, Dik; Ragas, Ad M J

    2015-09-01

    Species in the aquatic environment differ in their toxicological sensitivity to the various chemicals they encounter. In aquatic risk assessment, this interspecies variation is often quantified via species sensitivity distributions. Because the information available for the characterization of these distributions is typically limited, optimal use of information is essential to reduce uncertainty involved in the assessment. In the present study, we show that the credibility intervals on the estimated potentially affected fraction of species after exposure to a mixture of chemicals at environmentally relevant surface water concentrations can be extremely wide if a classical approach is followed, in which each chemical in the mixture is considered in isolation. As an alternative, we propose a hierarchical Bayesian approach, in which knowledge on the toxicity of chemicals other than those assessed is incorporated. A case study with a mixture of 13 pharmaceuticals demonstrates that this hierarchical approach results in more realistic estimations of the potentially affected fraction, as a result of reduced uncertainty in species sensitivity distributions for data-poor chemicals.

  13. Comparison of Chemical Composition of Complex Disinfection Byproduct (DBP) Mixtures Produced by Different Treatment Methods - slides

    EPA Science Inventory

    Analyses of the chemical composition of complex DBP mixtures, produced by different drinking water treatment processes, are essential to generate toxicity data required for assessing their risks to humans. For mixture risk assessments, whole mixture toxicology studies generally a...

  14. Toxicity testing of chemical mixtures: some general aspects and need of international guidelines.

    PubMed

    Kappus, H; Yang, R S

    1996-01-01

    The topics discussed by the Working Group on Toxicity Testing of Chemical Mixtures included the following (1) the study designs and results from two real-life exposure scenarios as additional information to the various investigations reported at the conference; (2) the need to take into consideration low-level, long-term exposure (i.e. mimicking human exposure conditions) as well as the issue of limited resources in experimental toxicology studies; (3) the importance of exploring alternative and predictive toxicology methodologies to minimize animal use and to conserve resources; (4) the realization that interactive toxicity should include the consideration of physical and biological agents in addition to chemicals. Two specific studies reported at the conference were also discussed. A number of recommendations were made concerning the planning and implementation of toxicology studies on chemical mixtures.

  15. Passive dosing of polycyclic aromatic hydrocarbon (PAH) mixtures to terrestrial springtails: linking mixture toxicity to chemical activities, equilibrium lipid concentrations, and toxic units.

    PubMed

    Schmidt, Stine N; Holmstrup, Martin; Smith, Kilian E C; Mayer, Philipp

    2013-07-02

    A 7-day mixture toxicity experiment with the terrestrial springtail Folsomia candida was conducted, and the effects were linked to three different mixture exposure parameters. Passive dosing from silicone was applied to tightly control exposure levels and compositions of 12 mixture treatments, containing the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. Springtail lethality was then linked to sum chemical activities (∑a), sum equilibrium lipid concentrations (∑C(lipid eq.)), and sum toxic units (∑TU). In each case, the effects of all 12 mixture treatments could be fitted to one sigmoidal exposure-response relationship. The effective lethal chemical activity (La50) of 0.027 was well within the expected range for baseline toxicity of 0.01-0.1. Linking the effects to the lipid-based exposure parameter yielded an effective lethal concentration (LC(lipid eq 50)) of 133 mmol kg(-1) lipid in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg(-1) lipid). Finally, the effective lethal toxic unit (LTU50) of 1.20 was rather close to the expected value of 1. Altogether, passive dosing provided tightly controlled mixture exposure in terms of both level and composition, while ∑a, ∑C(lipid eq.), and ∑TU allowed baseline toxicity to be linked to mixture exposure.

  16. Reduced chemical kinetic model of detonation combustion of one- and multi-fuel gaseous mixtures with air

    NASA Astrophysics Data System (ADS)

    Fomin, P. A.

    2018-03-01

    Two-step approximate models of chemical kinetics of detonation combustion of (i) one hydrocarbon fuel CnHm (for example, methane, propane, cyclohexane etc.) and (ii) multi-fuel gaseous mixtures (∑aiCniHmi) (for example, mixture of methane and propane, synthesis gas, benzene and kerosene) are presented for the first time. The models can be used for any stoichiometry, including fuel/fuels-rich mixtures, when reaction products contain molecules of carbon. Owing to the simplicity and high accuracy, the models can be used in multi-dimensional numerical calculations of detonation waves in corresponding gaseous mixtures. The models are in consistent with the second law of thermodynamics and Le Chatelier's principle. Constants of the models have a clear physical meaning. The models can be used for calculation thermodynamic parameters of the mixture in a state of chemical equilibrium.

  17. A nonlinear isobologram model with Box-Cox transformation to both sides for chemical mixtures.

    PubMed

    Chen, D G; Pounds, J G

    1998-12-01

    The linear logistical isobologram is a commonly used and powerful graphical and statistical tool for analyzing the combined effects of simple chemical mixtures. In this paper a nonlinear isobologram model is proposed to analyze the joint action of chemical mixtures for quantitative dose-response relationships. This nonlinear isobologram model incorporates two additional new parameters, Ymin and Ymax, to facilitate analysis of response data that are not constrained between 0 and 1, where parameters Ymin and Ymax represent the minimal and the maximal observed toxic response. This nonlinear isobologram model for binary mixtures can be expressed as [formula: see text] In addition, a Box-Cox transformation to both sides is introduced to improve the goodness of fit and to provide a more robust model for achieving homogeneity and normality of the residuals. Finally, a confidence band is proposed for selected isobols, e.g., the median effective dose, to facilitate graphical and statistical analysis of the isobologram. The versatility of this approach is demonstrated using published data describing the toxicity of the binary mixtures of citrinin and ochratoxin as well as a new experimental data from our laboratory for mixtures of mercury and cadmium.

  18. A nonlinear isobologram model with Box-Cox transformation to both sides for chemical mixtures.

    PubMed Central

    Chen, D G; Pounds, J G

    1998-01-01

    The linear logistical isobologram is a commonly used and powerful graphical and statistical tool for analyzing the combined effects of simple chemical mixtures. In this paper a nonlinear isobologram model is proposed to analyze the joint action of chemical mixtures for quantitative dose-response relationships. This nonlinear isobologram model incorporates two additional new parameters, Ymin and Ymax, to facilitate analysis of response data that are not constrained between 0 and 1, where parameters Ymin and Ymax represent the minimal and the maximal observed toxic response. This nonlinear isobologram model for binary mixtures can be expressed as [formula: see text] In addition, a Box-Cox transformation to both sides is introduced to improve the goodness of fit and to provide a more robust model for achieving homogeneity and normality of the residuals. Finally, a confidence band is proposed for selected isobols, e.g., the median effective dose, to facilitate graphical and statistical analysis of the isobologram. The versatility of this approach is demonstrated using published data describing the toxicity of the binary mixtures of citrinin and ochratoxin as well as a new experimental data from our laboratory for mixtures of mercury and cadmium. PMID:9860894

  19. Nature and prevalence of non-additive toxic effects in industrially relevant mixtures of organic chemicals.

    PubMed

    Parvez, Shahid; Venkataraman, Chandra; Mukherji, Suparna

    2009-06-01

    The concentration addition (CA) and the independent action (IA) models are widely used for predicting mixture toxicity based on its composition and individual component dose-response profiles. However, the prediction based on these models may be inaccurate due to interaction among mixture components. In this work, the nature and prevalence of non-additive effects were explored for binary, ternary and quaternary mixtures composed of hydrophobic organic compounds (HOCs). The toxicity of each individual component and mixture was determined using the Vibrio fischeri bioluminescence inhibition assay. For each combination of chemicals specified by the 2(n) factorial design, the percent deviation of the predicted toxic effect from the measured value was used to characterize mixtures as synergistic (positive deviation) and antagonistic (negative deviation). An arbitrary classification scheme was proposed based on the magnitude of deviation (d) as: additive (< or =10%, class-I) and moderately (10< d < or =30 %, class-II), highly (30< d < or =50%, class-III) and very highly (>50%, class-IV) antagonistic/synergistic. Naphthalene, n-butanol, o-xylene, catechol and p-cresol led to synergism in mixtures while 1, 2, 4-trimethylbenzene and 1, 3-dimethylnaphthalene contributed to antagonism. Most of the mixtures depicted additive or antagonistic effect. Synergism was prominent in some of the mixtures, such as, pulp and paper, textile dyes, and a mixture composed of polynuclear aromatic hydrocarbons. The organic chemical industry mixture depicted the highest abundance of antagonism and least synergism. Mixture toxicity was found to depend on partition coefficient, molecular connectivity index and relative concentration of the components.

  20. Should the scope of human mixture risk assessment span legislative/regulatory silos for chemicals?

    PubMed

    Evans, Richard M; Martin, Olwenn V; Faust, Michael; Kortenkamp, Andreas

    2016-02-01

    Current chemicals regulation operates almost exclusively on a chemical-by-chemical basis, however there is concern that this approach may not be sufficiently protective if two or more chemicals have the same toxic effect. Humans are indisputably exposed to more than one chemical at a time, for example to the multiple chemicals found in food, air and drinking water, and in household and consumer products, and in cosmetics. Assessment of cumulative risk to human health and/or the environment from multiple chemicals and routes can be done in a mixture risk assessment (MRA). Whilst there is a broad consensus on the basic science of mixture toxicology, the path to regulatory implementation of MRA within chemical risk assessment is less clear. In this discussion piece we pose an open question: should the scope of human MRA cross legislative remits or 'silos'? We define silos as, for instance, legislation that defines risk assessment practice for a subset of chemicals, usually on the basis of substance/product, media or process orientation. Currently any form of legal mandate for human MRA in the EU is limited to only a few pieces of legislation. We describe two lines of evidence, illustrated with selected examples, that are particularly pertinent to this question: 1) evidence that mixture effects have been shown for chemicals regulated in different silos and 2) evidence that humans are co-exposed to chemicals from different silos. We substantiate the position that, because there is no reason why chemicals allocated to specific regulatory silos would have non-overlapping risk profiles, then there is also no reason to expect that MRA limited only to chemicals within one silo can fully capture the risk that may be present to human consumers. Finally, we discuss possible options for implementation of MRA and we hope to prompt wider discussion of this issue. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  1. 78 FR 41768 - Chemical Substances and Mixtures Used in Oil and Gas Exploration or Production; TSCA Section 21...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-11

    ... Substances and Mixtures Used in Oil and Gas Exploration or Production; TSCA Section 21 Petition; Reasons for... processors of oil and gas exploration and production (E&P) chemical substances and mixtures to maintain... interest to you if you manufacture (including import), process, or distribute chemical substances or...

  2. Systematic Proteomic Approach to Characterize the Impacts of Chemical Interactions on Protein and Cytotoxicity Responses to Metal Mixture Exposures

    EPA Science Inventory

    Chemical interactions have posed a big challenge in toxicity characterization and human health risk assessment of environmental mixtures. To characterize the impacts of chemical interactions on protein and cytotoxicity responses to environmental mixtures, we established a systems...

  3. 40 CFR 180.1240 - Thymol; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Thymol; exemption from the requirement of a tolerance. 180.1240 Section 180.1240 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1240 Thymol;...

  4. 40 CFR 180.1307 - Bacteriophage of Clavibacter michiganensis subspecies michiganensis; exemption from the...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Bacteriophage of Clavibacter... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1307 Bacteriophage of... exemption from the requirement of a tolerance is established for residues of lytic bacteriophage of...

  5. 40 CFR 180.1307 - Bacteriophage of Clavibacter michiganensis subspecies michiganensis; exemption from the...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Bacteriophage of Clavibacter... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1307 Bacteriophage of... exemption from the requirement of a tolerance is established for residues of lytic bacteriophage of...

  6. 40 CFR 180.1307 - Bacteriophage of Clavibacter michiganensis subspecies michiganensis; exemption from the...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Bacteriophage of Clavibacter... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1307 Bacteriophage of... exemption from the requirement of a tolerance is established for residues of lytic bacteriophage of...

  7. From single chemicals to mixtures--reproductive effects of levonorgestrel and ethinylestradiol on the fathead minnow.

    PubMed

    Runnalls, Tamsin J; Beresford, Nicola; Kugathas, Subramaniam; Margiotta-Casaluci, Luigi; Scholze, Martin; Scott, Alexander P; Sumpter, John P

    2015-12-01

    The aquatic environment is polluted with thousands of chemicals. It is currently unclear which of these pose a significant threat to aquatic biota. The typical exposure scenario is now represented by a widespread blanket of contamination composed of myriads of individual pollutants-each typically present at a low concentration. The synthetic steroids, 17α-ethinylestradiol and levonorgestrel, have been widely reported to be present in the aquatic environment in the low ng to sub-ng/l range. They are widely used in contraceptive formulations, both individually and in combination. Our research employed the fathead minnow (Pimephales promelas) 21 day 'pair-breeding' assay to assess reproductive output when pairs of fish were exposed to the single chemicals at low environmentally relevant concentrations, and then to a binary mixture of them. A variety of endpoints were assessed, including egg production, which was inhibited in a concentration-dependent manner by both the individual chemicals and the mixture. Significant, sex specific effects were also seen with both chemicals, at differing levels of biological organisation. Plasma concentrations of EE2 and levonorgestrel were predicted and in the case of levonorgestrel measured, and compared with the human therapeutic plasma concentrations (Read-Across approach) to support the interpretation of the results. A novel quantitative method was developed for the data analysis, which ensured a suitable endpoint for the comparative mixture assessment. This approach compares the reproductive performance from individual pairs of fish during chemical exposure to its pre-treatment performance. The responses from the empirical mixture study were compared to predictions derived from the single substance data. We hypothesised combined responses which were best described by the concept of concentration addition, and found no clear indications against this additivity expectation. However, the effect profiles support the current

  8. 40 CFR 712.25 - Exempt manufacturers and importers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (1100 pounds) of the chemical substance at a single plant site are not subject to reporting for that... SUBSTANCES CONTROL ACT CHEMICAL INFORMATION RULES Manufacturers Reporting-Preliminary Assessment Information § 712.25 Exempt manufacturers and importers. (a) Persons who manufactured or imported the chemical...

  9. 40 CFR 712.25 - Exempt manufacturers and importers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (1100 pounds) of the chemical substance at a single plant site are not subject to reporting for that... SUBSTANCES CONTROL ACT CHEMICAL INFORMATION RULES Manufacturers Reporting-Preliminary Assessment Information § 712.25 Exempt manufacturers and importers. (a) Persons who manufactured or imported the chemical...

  10. 40 CFR 712.25 - Exempt manufacturers and importers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (1100 pounds) of the chemical substance at a single plant site are not subject to reporting for that... SUBSTANCES CONTROL ACT CHEMICAL INFORMATION RULES Manufacturers Reporting-Preliminary Assessment Information § 712.25 Exempt manufacturers and importers. (a) Persons who manufactured or imported the chemical...

  11. 40 CFR 712.25 - Exempt manufacturers and importers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (1100 pounds) of the chemical substance at a single plant site are not subject to reporting for that... SUBSTANCES CONTROL ACT CHEMICAL INFORMATION RULES Manufacturers Reporting-Preliminary Assessment Information § 712.25 Exempt manufacturers and importers. (a) Persons who manufactured or imported the chemical...

  12. 21 CFR 1308.31 - Application for exemption of a nonnarcotic prescription product.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... exemption of a nonnarcotic prescription product. (a) Any person seeking to have any compound, mixture, or... involved. The Administrator shall permit any interested person to file written comments on or objections to...

  13. 21 CFR 1309.26 - Exemption of law enforcement officials.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Exemption of law enforcement officials. 1309.26 Section 1309.26 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE REGISTRATION OF MANUFACTURERS, DISTRIBUTORS, IMPORTERS AND EXPORTERS OF LIST I CHEMICALS Requirements for Registration § 1309.26 Exemption of law enforcement...

  14. Convergence of the flow of a chemically reacting gaseous mixture to incompressible Euler equations in a unbounded domain

    NASA Astrophysics Data System (ADS)

    Kwon, Young-Sam

    2017-12-01

    The flow of chemically reacting gaseous mixture is associated with a variety of phenomena and processes. We study the combined quasineutral and inviscid limit from the flow of chemically reacting gaseous mixture governed by Poisson equation to incompressible Euler equations with the ill-prepared initial data in the unbounded domain R^2× T. Furthermore, the convergence rates are obtained.

  15. 40 CFR 180.1049 - Carbon dioxide; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Carbon dioxide; exemption from the requirement of a tolerance. 180.1049 Section 180.1049 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1049 Carbo...

  16. 40 CFR 180.1049 - Carbon dioxide; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Carbon dioxide; exemption from the requirement of a tolerance. 180.1049 Section 180.1049 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1049 Carbo...

  17. 40 CFR 180.1049 - Carbon dioxide; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Carbon dioxide; exemption from the requirement of a tolerance. 180.1049 Section 180.1049 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1049 Carbo...

  18. Toxicity of a hazardous chemical mixture in the planarian, Dugesia dorotocephala

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ramsdell, H.S.; Matthews, C.M.

    1995-12-31

    The responses of the planarian, Dugesia dorotocephala to toxic chemical mixtures representative of water contaminants associated with hazardous waste sites have been studied in laboratory experiments. These free-living flatworms are readily maintained under laboratory conditions and are a useful invertebrate model for toxicology studies. Their widespread occurrence also makes them potentially useful for environmental studies. Mature asexual Dugesia dorotocephala were exposed for 14 days to mixtures of seven contaminants frequently detected in water at hazardous waste sites. The complete 1X mixture contained both metals (As, 3.1 ppm; Cr, 0.7 ppm; Pb, 3.7 ppm) and organics (chloroform, 1.5 ppm; benzene, 5.0more » ppm; phenol, 3.4 ppm; trichloroethylene, 3.8 ppm). Groups of planaria were treated with the complete mixture at 0.1X, 1X and 10X concentrations. Additional groups were exposed to the metals-only or organics-only submixtures, also at 0.1X, 1X and 10X concentrations. Treatment solutions were renewed daily. Suppression of fissioning was observed in all of the 1X and 10X treatment groups. Significant mortality occurred only in the 10X complete and 1 0X metals-only treatments. It appears that the toxic effects of the complete mixture are primarily associated with the metal components.« less

  19. 40 CFR 180.1095 - Chlorine gas; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... gas is exempted from the requirement of a tolerance when used preharvest or postharvest in solution on...

  20. 40 CFR 180.1095 - Chlorine gas; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... gas is exempted from the requirement of a tolerance when used preharvest or postharvest in solution on...

  1. 40 CFR 180.1176 - Sodium bicarbonate; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... biochemical pesticide sodium bicarbonate is exempted from the requirement of a tolerance in or on all raw...

  2. 40 CFR 180.1097 - GBM-ROPE; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD...-tetradecenyl acetate is exempt from the requirement of a tolerance in or on the raw agricultural commodity...

  3. 40 CFR 180.1097 - GBM-ROPE; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD...-tetradecenyl acetate is exempt from the requirement of a tolerance in or on the raw agricultural commodity...

  4. 40 CFR 180.1176 - Sodium bicarbonate; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... biochemical pesticide sodium bicarbonate is exempted from the requirement of a tolerance in or on all raw...

  5. 40 CFR 180.1041 - Nosema locustae; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... insecticide Nosema locustae is exempted from the requirement of a tolerance for residues in or on all raw...

  6. 40 CFR 180.1041 - Nosema locustae; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... insecticide Nosema locustae is exempted from the requirement of a tolerance for residues in or on all raw...

  7. A Four-Step and Four-Criteria Approach for Evaluating Evidence of Dose Addition in Chemical Mixture Toxicity

    EPA Science Inventory

    Dose addition is the most frequently-used component-based approach for predicting dose response for a mixture of toxicologically-similar chemicals and for statistical evaluation of whether the mixture response is consistent with dose additivity and therefore predictable from the ...

  8. Biologically-Based Lumping Methodology (BBLM) To Investigate Toxicological Interactions of Complex Chemical Mixtures

    EPA Science Inventory

    Many cases of environmental contamination result in concurrent or sequential exposure to more than one chemical. Limitations of available resources prevent experimental toxicology from providing health risk information about all the possible mixtures to which humans or other spec...

  9. Impact of Chemical Proportions on the Acute Neurotoxicity of a Mixture of Seven Carbamates in Rats

    EPA Science Inventory

    Environmental exposures generally involve multiple chemicals and pathways, and statistical methodologies now exist to evaluate interactions among any number of chemicals in defined mixtures. N-methyl carbamate pesticides are presumed to act through a common mode of action, that i...

  10. 40 CFR 180.1080 - Plant volatiles and pheromone; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Plant volatiles and pheromone... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1080 Plant volatiles and pheromone; exemptions from the...

  11. 40 CFR 180.1080 - Plant volatiles and pheromone; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Plant volatiles and pheromone... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1080 Plant volatiles and pheromone; exemptions from the...

  12. 40 CFR 180.1080 - Plant volatiles and pheromone; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Plant volatiles and pheromone... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1080 Plant volatiles and pheromone; exemptions from the...

  13. 40 CFR 180.1080 - Plant volatiles and pheromone; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Plant volatiles and pheromone... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1080 Plant volatiles and pheromone; exemptions from the...

  14. Chemical mixtures and environmental effects: a pilot study to assess ecological exposure and effects in streams

    USGS Publications Warehouse

    Buxton, Herbert T.; Reilly, Timothy J.; Kuivila, Kathryn; Kolpin, Dana W.; Bradley, Paul M.; Villeneuve, Daniel L.; Mills, Marc A.

    2015-01-01

    Assessment and management of the risks of exposure to complex chemical mixtures in streams are priorities for human and environmental health organizations around the world. The current lack of information on the composition and variability of environmental mixtures and a limited understanding of their combined effects are fundamental obstacles to timely identification and prevention of adverse human and ecological effects of exposure. This report describes the design of a field-based study of the composition and biological activity of chemical mixtures in U.S. stream waters affected by a wide range of human activities and contaminant sources. The study is a collaborative effort by the U.S. Geological Survey and the U.S. Environmental Protection Agency. Scientists sampled 38 streams spanning 24 States and Puerto Rico. Thirty-four of the sites were located in watersheds impacted by multiple contaminant sources, including industrial and municipal wastewater discharges, crop and animal agricultural runoff, urban runoff, and other point and nonpoint contaminant sources. The remaining four sites were minimally development reference watersheds. All samples underwent comprehensive chemical and biological characterization, including sensitive and specific direct analysis for over 700 dissolved organic and inorganic chemicals and field parameters, identification of unknown contaminants (environmental diagnostics), and a variety of bioassays to evaluate biological activity and toxicity.

  15. In vitro test systems supporting the development of improved pest control methods: a case study with chemical mixtures and bivalve biofoulers.

    PubMed

    Silva, Carlos; Nunes, Bruno; Nogueira, António Ja; Gonçalves, Fernando; Pereira, Joana L

    2016-11-01

    Using the bivalve macrofouler Corbicula fluminea, the suitability of in vitro testing as a stepping stone towards the improvement of control methods based on chemical mixtures was addressed in this study. In vitro cholinesterase (ChE) activity inhibition following single exposure of C. fluminea tissue to four model chemicals (the organophosphates dimethoate and dichlorvos, copper and sodium dodecyl phosphate [SDS]) was first assessed. Consequently, mixtures of dimethoate with copper and dichlorvos with SDS were tested and modelled; mixtures with ChE revealed synergistic interactions for both chemical pairs. These synergic combinations were subsequently validated in vivo and the increased control potential of these selected combinations was verified, with gains of up to 50% in C. fluminea mortality relative to corresponding single chemical treatments. Such consistency supports the suitability of using time- and cost-effective surrogate testing platforms to assist the development of biofouling control strategies incorporating mixtures.

  16. Toxicology of chemical mixtures: Experimental approaches, underlying concepts, and some results

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yang, R.S.; Long, H.L.; Boorman, G.A.

    1990-07-01

    The toxicology of chemical mixtures will be the toxicology of the 1990s and beyond. While this branch of toxicology most closely reflects the actual human exposure situation, as yet there is no standard protocol or consensus methodology for investigating the toxicology of mixtures. Thus, in this emerging science, experimentation is required just to develop a broadly applicable evaluation system. Several examples are discussed to illustrate the different experimental designs and the concepts behind each. These include the health effects studies of Love Canal soil samples, the Lake Ontario Coho salmon, the water samples repurified from secondary sewage in the citymore » of Denver Potable Water Reuse Demonstration Plant, and the National Toxicology Program (NTP) effort on a mixture of 25 frequently detected groundwater contaminants derived from hazardous waste disposal sites. In the last instance, an extensive research program has been ongoing for the last two years at the NTP, encompassing general toxicology, immunotoxicology, developmental and reproductive toxicology, biochemical toxicology, myelotoxicology, genetic toxicology, neurobehavioral toxicology, and hepato- and renal toxicology.« less

  17. Supersonic Flow of Chemically Reacting Gas-Particle Mixtures. Volume 2: RAMP - A Computer Code for Analysis of Chemically Reacting Gas-Particle Flows

    NASA Technical Reports Server (NTRS)

    Penny, M. M.; Smith, S. D.; Anderson, P. G.; Sulyma, P. R.; Pearson, M. L.

    1976-01-01

    A computer program written in conjunction with the numerical solution of the flow of chemically reacting gas-particle mixtures was documented. The solution to the set of governing equations was obtained by utilizing the method of characteristics. The equations cast in characteristic form were shown to be formally the same for ideal, frozen, chemical equilibrium and chemical non-equilibrium reacting gas mixtures. The characteristic directions for the gas-particle system are found to be the conventional gas Mach lines, the gas streamlines and the particle streamlines. The basic mesh construction for the flow solution is along streamlines and normals to the streamlines for axisymmetric or two-dimensional flow. The analysis gives detailed information of the supersonic flow and provides for a continuous solution of the nozzle and exhaust plume flow fields. Boundary conditions for the flow solution are either the nozzle wall or the exhaust plume boundary.

  18. Disclosure of hydraulic fracturing fluid chemical additives: analysis of regulations.

    PubMed

    Maule, Alexis L; Makey, Colleen M; Benson, Eugene B; Burrows, Isaac J; Scammell, Madeleine K

    2013-01-01

    Hydraulic fracturing is used to extract natural gas from shale formations. The process involves injecting into the ground fracturing fluids that contain thousands of gallons of chemical additives. Companies are not mandated by federal regulations to disclose the identities or quantities of chemicals used during hydraulic fracturing operations on private or public lands. States have begun to regulate hydraulic fracturing fluids by mandating chemical disclosure. These laws have shortcomings including nondisclosure of proprietary or "trade secret" mixtures, insufficient penalties for reporting inaccurate or incomplete information, and timelines that allow for after-the-fact reporting. These limitations leave lawmakers, regulators, public safety officers, and the public uninformed and ill-prepared to anticipate and respond to possible environmental and human health hazards associated with hydraulic fracturing fluids. We explore hydraulic fracturing exemptions from federal regulations, as well as current and future efforts to mandate chemical disclosure at the federal and state level.

  19. Enhancing the Benefit of the Chemical Mixture Methodology: A Report on Methodology Testing and Potential Approaches for Improving Performance

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yu, Xiao-Ying; Yao, Juan; He, Hua

    2012-01-01

    Extensive testing shows that the current version of the Chemical Mixture Methodology (CMM) is meeting its intended mission to provide conservative estimates of the health effects from exposure to airborne chemical mixtures. However, the current version of the CMM could benefit from several enhancements that are designed to improve its application of Health Code Numbers (HCNs) and employ weighting factors to reduce over conservatism.

  20. Impact of chemical proportions on the acute neurotoxicity of a mixture of seven carbamates in preweanling and adult rats.

    PubMed

    Moser, Virginia C; Padilla, Stephanie; Simmons, Jane Ellen; Haber, Lynne T; Hertzberg, Richard C

    2012-09-01

    Statistical design and environmental relevance are important aspects of studies of chemical mixtures, such as pesticides. We used a dose-additivity model to test experimentally the default assumptions of dose additivity for two mixtures of seven N-methylcarbamates (carbaryl, carbofuran, formetanate, methomyl, methiocarb, oxamyl, and propoxur). The best-fitting models were selected for the single-chemical dose-response data and used to develop a combined prediction model, which was then compared with the experimental mixture data. We evaluated behavioral (motor activity) and cholinesterase (ChE)-inhibitory (brain, red blood cells) outcomes at the time of peak acute effects following oral gavage in adult and preweanling (17 days old) Long-Evans male rats. The mixtures varied only in their mixing ratios. In the relative potency mixture, proportions of each carbamate were set at equitoxic component doses. A California environmental mixture was based on the 2005 sales of each carbamate in California. In adult rats, the relative potency mixture showed dose additivity for red blood cell ChE and motor activity, and brain ChE inhibition showed a modest greater-than additive (synergistic) response, but only at a middle dose. In rat pups, the relative potency mixture was either dose-additive (brain ChE inhibition, motor activity) or slightly less-than additive (red blood cell ChE inhibition). On the other hand, at both ages, the environmental mixture showed greater-than additive responses on all three endpoints, with significant deviations from predicted at most to all doses tested. Thus, we observed different interactive properties for different mixing ratios of these chemicals. These approaches for studying pesticide mixtures can improve evaluations of potential toxicity under varying experimental conditions that may mimic human exposures.

  1. TOXICITY AND MUTAGENICITY OF A MIXTURE OF 25 CHEMICALS FOUND IN CONTAMINATED GROUNDWATER

    EPA Science Inventory

    A defined mixture of 25 chemicals that are often found in contaminated ground water was prepared as a water solution and studied for mutagenicity in bacteria, for prophage induction in bacteria, for palatability and effect on weight-gain in rats and mice, and for cytogenetic effe...

  2. General baseline toxicity QSAR for nonpolar, polar and ionisable chemicals and their mixtures in the bioluminescence inhibition assay with Aliivibrio fischeri.

    PubMed

    Escher, Beate I; Baumer, Andreas; Bittermann, Kai; Henneberger, Luise; König, Maria; Kühnert, Christin; Klüver, Nils

    2017-03-22

    The Microtox assay, a bioluminescence inhibition assay with the marine bacterium Aliivibrio fischeri, is one of the most popular bioassays for assessing the cytotoxicity of organic chemicals, mixtures and environmental samples. Most environmental chemicals act as baseline toxicants in this short-term screening assay, which is typically run with only 30 min of exposure duration. Numerous Quantitative Structure-Activity Relationships (QSARs) exist for the Microtox assay for nonpolar and polar narcosis. However, typical water pollutants, which have highly diverse structures covering a wide range of hydrophobicity and speciation from neutral to anionic and cationic, are often outside the applicability domain of these QSARs. To include all types of environmentally relevant organic pollutants we developed a general baseline toxicity QSAR using liposome-water distribution ratios as descriptors. Previous limitations in availability of experimental liposome-water partition constants were overcome by reliable prediction models based on polyparameter linear free energy relationships for neutral chemicals and the COSMOmic model for charged chemicals. With this QSAR and targeted mixture experiments we could demonstrate that ionisable chemicals fall in the applicability domain. Most investigated water pollutants acted as baseline toxicants in this bioassay, with the few outliers identified as uncouplers or reactive toxicants. The main limitation of the Microtox assay is that chemicals with a high melting point and/or high hydrophobicity were outside of the applicability domain because of their low water solubility. We quantitatively derived a solubility cut-off but also demonstrated with mixture experiments that chemicals inactive on their own can contribute to mixture toxicity, which is highly relevant for complex environmental mixtures, where these chemicals may be present at concentrations below the solubility cut-off.

  3. 40 CFR 180.1285 - Polyoxin D zinc salt; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Polyoxin D zinc salt; exemption from the requirement of a tolerance. 180.1285 Section 180.1285 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1285...

  4. 40 CFR 180.1285 - Polyoxin D zinc salt; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Polyoxin D zinc salt; exemption from the requirement of a tolerance. 180.1285 Section 180.1285 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1285...

  5. 40 CFR 180.1285 - Polyoxin D zinc salt; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Polyoxin D zinc salt; exemption from the requirement of a tolerance. 180.1285 Section 180.1285 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1285...

  6. 40 CFR 180.1071 - Peanuts, Tree Nuts, Milk, Soybeans, Eggs, Fish, Crustacea, and Wheat; exemption from the...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1071... fertilizer on which an active ingredient is impregnated. (11) Aerial and ground applications that occur when... peanut meal when applied to peanut plants. (b) Specific chemical substances. Residues resulting from the...

  7. 40 CFR 180.1071 - Peanuts, Tree Nuts, Milk, Soybeans, Eggs, Fish, Crustacea, and Wheat; exemption from the...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1071... fertilizer on which an active ingredient is impregnated. (11) Aerial and ground applications that occur when... peanut meal when applied to peanut plants. (b) Specific chemical substances. Residues resulting from the...

  8. 40 CFR 180.1071 - Peanuts, Tree Nuts, Milk, Soybeans, Eggs, Fish, Crustacea, and Wheat; exemption from the...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1071... fertilizer on which an active ingredient is impregnated. (11) Aerial and ground applications that occur when... peanut meal when applied to peanut plants. (b) Specific chemical substances. Residues resulting from the...

  9. 77 FR 76979 - Pesticides; Revisions to Minimum Risk Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-31

    ...EPA is proposing to more clearly describe the active and inert ingredients permitted in products eligible for the exemption from regulation for minimum risk pesticides. EPA is proposing to reorganize these lists with a focus on clarity and transparency by adding specific chemical identifiers. The identifiers would make it clearer to manufacturers; the public; and Federal, state, and tribal inspectors which ingredients are permitted in minimum risk pesticide products. EPA is also proposing to modify the label requirements in the exemption to require the use of specific common chemical names in lists of ingredients on minimum risk pesticide product labels, and to require producer contact information on the label. Once final, these proposed changes would maintain the availability of minimum risk pesticide products while providing more consistent information for consumers, clearer regulations for producers, and easier identification by states, tribes and EPA as to whether a product is in compliance with the exemption.

  10. MIXTURES OF THYROID DISRUPTING CHEMICALS: TESTING ADDITIVITY OF HEPATIC INDUCERS AND THYROID PEROXIDASE INHIBITORS.

    EPA Science Inventory

    Humans are exposed to chemical mixtures via diet, occupation, and the environment. Previous data demonstrated that low doses of polycyclic halogenated aromatic hydrocarbons (PHAHs) acting through similar mechanisms result in an additive reduction of thyroxine (T4). If xenobioti...

  11. AGONISTIC SENSORY EFFECTS OF AIRBORNE CHEMICALS IN MIXTURES: ODOR, NASAL PUNGENCY, AND EYE IRRITATION

    EPA Science Inventory

    Threshold responses of odor, nasal pungency (irritation), and eye irritation were measured for single chemicals (1-propanol, 1-hexanol, ethyl acetate, heptyl acetate, 2-pentanone, 2-heptanone, toluene, ethyl benzene, and propyl benzene) and mixtures of them (two three-component m...

  12. Human exposure to chemical mixtures: Challenges for the integration of toxicology with epidemiology data in risk assessment.

    PubMed

    Hernández, Antonio F; Tsatsakis, Aristidis M

    2017-05-01

    Little is known about the potential adverse effects from longterm exposure to complex mixtures at low doses, close to health-based reference values. Traditional chemical-specific risk assessment based on animal testing may be insufficient and the lack of toxicological studies on chemical mixtures remains a major regulatory challenge. Hence, new methodologies on cumulative risk assessment are being developed but still present major limitations. Evaluation of chemical mixture effects requires an integrated and systematic approach and close collaboration across different scientific fields, particularly toxicology, epidemiology, exposure science, risk assessment and statistics for a proper integration of data from all these disciplines. Well designed and conducted epidemiological studies can take advantage of this new paradigm and can provide insight to support the correlation between humans low-dose exposures and diseases, thus avoiding the uncertainty associated with extrapolation across species. In this regard, human epidemiology studies may play a significant role in the new vision of toxicity testing. However, this type of information has not been fully considered in risk assessment, mainly due to the inherent limitations of epidemiologic studies. An integrated approach of in vivo, in vitro and in silico data, together with systematic reviews or meta-analysis of high quality epidemiological studies will improve the robustness of risk assessment of chemical mixtures and will provide a stronger basis for regulatory decisions. The ultimate goal is that experimental and mechanistic data can lend support and biological plausibility to the human epidemiological observations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. 40 CFR 180.1087 - Sesame stalks; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... exemption from the requirement of a tolerance is established for residues of the biorational nematicide... fractions; potato; beet, sugar, roots; beet, sugar, tops; tomato; pepper, bell; squash; strawberry; eggplant...

  14. 40 CFR 180.1087 - Sesame stalks; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... exemption from the requirement of a tolerance is established for residues of the biorational nematicide... fractions; potato; beet, sugar, roots; beet, sugar, tops; tomato; pepper, bell; squash; strawberry; eggplant...

  15. 40 CFR 720.38 - Exemptions for test marketing.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... or, in the absence of such data, a discussion of toxicity based on structure-activity relationships (SAR) and relevant data on chemical analogues. (2) The maximum quantity of the chemical substance which.... (c) In accordance with section 5(h)(6) of the Act, after EPA receives an application for exemption...

  16. A modeling approach to account for toxicokinetic interactions in the calculation of biological hazard index for chemical mixtures.

    PubMed

    Haddad, S; Tardif, R; Viau, C; Krishnan, K

    1999-09-05

    Biological hazard index (BHI) is defined as biological level tolerable for exposure to mixture, and is calculated by an equation similar to the conventional hazard index. The BHI calculation, at the present time, is advocated for use in situations where toxicokinetic interactions do not occur among mixture constituents. The objective of this study was to develop an approach for calculating interactions-based BHI for chemical mixtures. The approach consisted of simulating the concentration of exposure indicator in the biological matrix of choice (e.g. venous blood) for each component of the mixture to which workers are exposed and then comparing these to the established BEI values, for calculating the BHI. The simulation of biomarker concentrations was performed using a physiologically-based toxicokinetic (PBTK) model which accounted for the mechanism of interactions among all mixture components (e.g. competitive inhibition). The usefulness of the present approach is illustrated by calculating BHI for varying ambient concentrations of a mixture of three chemicals (toluene (5-40 ppm), m-xylene (10-50 ppm), and ethylbenzene (10-50 ppm)). The results show that the interactions-based BHI can be greater or smaller than that calculated on the basis of additivity principle, particularly at high exposure concentrations. At lower exposure concentrations (e.g. 20 ppm each of toluene, m-xylene and ethylbenzene), the BHI values obtained using the conventional methodology are similar to the interactions-based methodology, confirming that the consequences of competitive inhibition are negligible at lower concentrations. The advantage of the PBTK model-based methodology developed in this study relates to the fact that, the concentrations of individual chemicals in mixtures that will not result in a significant increase in the BHI (i.e. > 1) can be determined by iterative simulation.

  17. Characterization of the pharmacokinetics of gasoline using PBPK modeling with a complex mixtures chemical lumping approach.

    PubMed

    Dennison, James E; Andersen, Melvin E; Yang, Raymond S H

    2003-09-01

    Gasoline consists of a few toxicologically significant components and a large number of other hydrocarbons in a complex mixture. By using an integrated, physiologically based pharmacokinetic (PBPK) modeling and lumping approach, we have developed a method for characterizing the pharmacokinetics (PKs) of gasoline in rats. The PBPK model tracks selected target components (benzene, toluene, ethylbenzene, o-xylene [BTEX], and n-hexane) and a lumped chemical group representing all nontarget components, with competitive metabolic inhibition between all target compounds and the lumped chemical. PK data was acquired by performing gas uptake PK studies with male F344 rats in a closed chamber. Chamber air samples were analyzed every 10-20 min by gas chromatography/flame ionization detection and all nontarget chemicals were co-integrated. A four-compartment PBPK model with metabolic interactions was constructed using the BTEX, n-hexane, and lumped chemical data. Target chemical kinetic parameters were refined by studies with either the single chemical alone or with all five chemicals together. o-Xylene, at high concentrations, decreased alveolar ventilation, consistent with respiratory irritation. A six-chemical interaction model with the lumped chemical group was used to estimate lumped chemical partitioning and metabolic parameters for a winter blend of gasoline with methyl t-butyl ether and a summer blend without any oxygenate. Computer simulation results from this model matched well with experimental data from single chemical, five-chemical mixture, and the two blends of gasoline. The PBPK model analysis indicated that metabolism of individual components was inhibited up to 27% during the 6-h gas uptake experiments of gasoline exposures.

  18. Atomic charges of individual reactive chemicals in binary mixtures determine their joint effects: an example of cyanogenic toxicants and aldehydes.

    PubMed

    Tian, Dayong; Lin, Zhifen; Yin, Daqiang; Zhang, Yalei; Kong, Deyang

    2012-02-01

    Environmental contaminants are usually encountered as mixtures, and many of these mixtures yield synergistic or antagonistic effects attributable to an intracellular chemical reaction that pose a potential threat on ecological systems. However, how atomic charges of individual chemicals determine their intracellular chemical reactions, and then determine the joint effects for mixtures containing reactive toxicants, is not well understood. To address this issue, the joint effects between cyanogenic toxicants and aldehydes on Photobacterium phosphoreum were observed in the present study. Their toxicological joint effects differed from one another. This difference is inherently related to the two atomic charges of the individual chemicals: the oxygen charge of -CHO (O(aldehyde toxicant)) in aldehyde toxicants and the carbon-atom charge of a carbon chain in the cyanogenic toxicant (C(cyanogenic toxicant)). Based on these two atomic charges, the following QSAR (quantitative structure-activity relationship) model was proposed: When (O(aldehyde toxicant) -C(cyanogenic toxicant) )> -0.125, the joint effect of equitoxic binary mixtures at median inhibition (TU, the sum of toxic units) can be calculated as TU = 1.00 ± 0.20; when (O(aldehyde toxicant) -C(cyanogenic toxicant) ) ≤ -0.125, the joint effect can be calculated using TU = - 27.6 x O (aldehyde toxicant) - 5.22 x C (cyanogenic toxicant) - 6.97 (n = 40, r = 0.887, SE = 0.195, F = 140, p < 0.001, q(2) (Loo) = 0.748; SE is the standard error of the regression, F is the F test statistic). The result provides insight into the relationship between the atomic charges and the joint effects for mixtures containing cyanogenic toxicants and aldehydes. This demonstrates that the essence of the joint effects resulting from intracellular chemical reactions depends on the atomic charges of individual chemicals. The present study provides a possible approach for the development of a QSAR model for mixtures containing reactive

  19. Testing for Additivity in Chemical Mixtures Using a Fixed-Ratio Ray Design and Statistical Equivalence Testing Methods

    EPA Science Inventory

    Fixed-ratio ray designs have been used for detecting and characterizing interactions of large numbers of chemicals in combination. Single chemical dose-response data are used to predict an “additivity curve” along an environmentally relevant ray. A “mixture curve” is estimated fr...

  20. 40 CFR 180.1237 - Sodium metasilicate; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN... aqueous solution. (b) An exemption from the requirement of a tolerance is established for residues of... not exceed 2.41% by weight in aqueous solution. [71 FR 19441, Apr. 14, 2006] ...

  1. 40 CFR 180.1237 - Sodium metasilicate; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN... aqueous solution. (b) An exemption from the requirement of a tolerance is established for residues of... not exceed 2.41% by weight in aqueous solution. [71 FR 19441, Apr. 14, 2006] ...

  2. CHANGES IN HIPPOCAMPAL SPINE DENSITY AND PROTEIN KINASE C ISOFORMS FOLLOWING DEVELOPMENTAL EXPOSURE TO A MIXTURE OF PERSISTENT CHEMICALS.

    EPA Science Inventory

    Polychlorinated biphenyls (PCBs) offer a unique model to understand the major issues related to complex environmental mixtures of persistent chemicals. These pollutants are ubiquitous, persistent, bioaccumulate in human body through the food chain, and exist as mixtures of severa...

  3. Evaluating the aquatic toxicity of complex organic chemical mixtures: lessons learned from polycyclic aromatic hydrocarbon and petroleum hydrocarbon case studies.

    PubMed

    Landrum, Peter F; Chapman, Peter M; Neff, Jerry; Page, David S

    2012-04-01

    Experimental designs for evaluating complex mixture toxicity in aquatic environments can be highly variable and, if not appropriate, can produce and have produced data that are difficult or impossible to interpret accurately. We build on and synthesize recent critical reviews of mixture toxicity using lessons learned from 4 case studies, ranging from binary to more complex mixtures of primarily polycyclic aromatic hydrocarbons and petroleum hydrocarbons, to provide guidance for evaluating the aquatic toxicity of complex mixtures of organic chemicals. Two fundamental requirements include establishing a dose-response relationship and determining the causative agent (or agents) of any observed toxicity. Meeting these 2 requirements involves ensuring appropriate exposure conditions and measurement endpoints, considering modifying factors (e.g., test conditions, test organism life stages and feeding behavior, chemical transformations, mixture dilutions, sorbing phases), and correctly interpreting dose-response relationships. Specific recommendations are provided. Copyright © 2011 SETAC.

  4. Impact of Chemical Proportions on the Acute Neurotoxicity of a Mixture of Seven Carbamates in Preweanling and Adult Rats

    EPA Science Inventory

    Statistical design and environmental relevance are important aspects of studies of chemical mixtures, such as pesticides. We used a dose-additivity model to test experimentally the default assumptions of dose-additivity for two mixtures of seven N-methylcarbamates (carbaryl, carb...

  5. TSCA Section 21 Petition for Section 8(a) Partial Exemption

    EPA Pesticide Factsheets

    This petition requests EPA to amend the TSCA Section 8 Chemical Data Reporting (CDR) partially exempted chemical list set forth in the U.S. Environmental Protection Agency’s (EPA) regulations at 40 C.F.R. Section 711.6(b)(1).

  6. Mixtures and their risk assessment in toxicology.

    PubMed

    Mumtaz, Moiz M; Hansen, Hugh; Pohl, Hana R

    2011-01-01

    For communities generally and for persons living in the vicinity of waste sites specifically, potential exposures to chemical mixtures are genuine concerns. Such concerns often arise from perceptions of a site's higher than anticipated toxicity due to synergistic interactions among chemicals. This chapter outlines some historical approaches to mixtures risk assessment. It also outlines ATSDR's current approach to toxicity risk assessment. The ATSDR's joint toxicity assessment guidance for chemical mixtures addresses interactions among components of chemical mixtures. The guidance recommends a series of steps that include simple calculations for a systematic analysis of data leading to conclusions regarding any hazards chemical mixtures might pose. These conclusions can, in turn, lead to recommendations such as targeted research to fill data gaps, development of new methods using current science, and health education to raise awareness of residents and health care providers. The chapter also provides examples of future trends in chemical mixtures assessment.

  7. ADDITIVITY ASSESSMENT OF TRIHALOMETHANE MIXTURES BY PROPORTIONAL RESPONSE ADDITION

    EPA Science Inventory

    If additivity is known or assumed, the toxicity of a chemical mixture may be predicted from the dose response curves of the individual chemicals comprising the mixture. As single chemical data are abundant and mixture data sparse, mixture risk methods that utilize single chemical...

  8. 7 CFR 1205.519 - Organic exemption.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... under an approved National Organic Program (NOP) (7 CFR part 205) system plan; produces only products... an exemption from assessment on 100 percent organic cotton and 100 percent organic cotton products—on... for organic products, isolated use of antibiotics for humane purposes, chemical or pesticide use as...

  9. 40 CFR 180.1210 - Phosphorous acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... exemption from the requirement of a tolerance is established for residues of phosphorous acid and its... and in or on potatoes when applied as a post-harvest treatment at 35,600 ppm or less phosphorous acid...

  10. 40 CFR 180.1210 - Phosphorous acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... exemption from the requirement of a tolerance is established for residues of phosphorous acid and its... and in or on potatoes when applied as a post-harvest treatment at 35,600 ppm or less phosphorous acid...

  11. 40 CFR 180.1225 - Decanoic acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... exemption from the requirement of a tolerance is established for residues of decanoic acid in or on all raw... acid (up to 170 ppm per application) on food contact surfaces such as equipment, pipelines, tanks, vats...

  12. 40 CFR 180.1142 - 1,4-Dimethylnaphthalene; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN... tolerance. An exemption from the requirement of a tolerance is established for residues of the plant growth regulator 1,4-dimethylnaphthalene when applied post harvest to potatoes in accordance with good agricultural...

  13. 40 CFR 180.1142 - 1,4-Dimethylnaphthalene; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN... tolerance. An exemption from the requirement of a tolerance is established for residues of the plant growth regulator 1,4-dimethylnaphthalene when applied post harvest to potatoes in accordance with good agricultural...

  14. Chemical composition and binary mixture of human urinary stones using FT-Raman spectroscopy method.

    PubMed

    Selvaraju, R; Raja, A; Thiruppathi, G

    2013-10-01

    In the present study the human urinary stones were observed in their different chemical compositions of calcium oxalate monohydrate, calcium oxalate dihydrate, calcium phosphate, struvite (magnesium ammonium phosphate), uric acid, cystine, oxammite (ammonium oxalate monohydrate), natroxalate (sodium oxalate), glushinkite (magnesium oxalate dihydrate) and moolooite (copper oxalate) were analyzed using Fourier Transform-Raman (FT-Raman) spectroscopy. For the quantitative analysis, various human urinary stone samples are used for ratios calculation of binary mixtures compositions such as COM/COD, HAP/COD, HAP/COD, Uric acid/COM, uric acid/COD and uric acid/HAP. The calibration curve is used for further analysis of binary mixture of human urinary stones. For the binary mixture calculation the various intensities bands at 1462 cm(-1) (I(COM)), 1473 cm(-1) (I(COD)), 961 cm(-1) (I(HAP)) and 1282 cm(-1) (I(UA)) were used. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Gene expression profiles in rainbow trout, Onchorynchus mykiss, exposed to a simple chemical mixture.

    PubMed

    Hook, Sharon E; Skillman, Ann D; Gopalan, Banu; Small, Jack A; Schultz, Irvin R

    2008-03-01

    Among proposed uses for microarrays in environmental toxiciology is the identification of key contributors to toxicity within a mixture. However, it remains uncertain whether the transcriptomic profiles resulting from exposure to a mixture have patterns of altered gene expression that contain identifiable contributions from each toxicant component. We exposed isogenic rainbow trout Onchorynchus mykiss, to sublethal levels of ethynylestradiol, 2,2,4,4-tetrabromodiphenyl ether, and chromium VI or to a mixture of all three toxicants Fluorescently labeled complementary DNA (cDNA) were generated and hybridized against a commercially available Salmonid array spotted with 16,000 cDNAs. Data were analyzed using analysis of variance (p<0.05) with a Benjamani-Hochberg multiple test correction (Genespring [Agilent] software package) to identify up and downregulated genes. Gene clustering patterns that can be used as "expression signatures" were determined using hierarchical cluster analysis. The gene ontology terms associated with significantly altered genes were also used to identify functional groups that were associated with toxicant exposure. Cross-ontological analytics approach was used to assign functional annotations to genes with "unknown" function. Our analysis indicates that transcriptomic profiles resulting from the mixture exposure resemble those of the individual contaminant exposures, but are not a simple additive list. However, patterns of altered genes representative of each component of the mixture are clearly discernible, and the functional classes of genes altered represent the individual components of the mixture. These findings indicate that the use of microarrays to identify transcriptomic profiles may aid in the identification of key stressors within a chemical mixture, ultimately improving environmental assessment.

  16. 76 FR 51431 - Prohibited Transaction Exemptions and Grant of Individual Exemptions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-18

    ... DEPARTMENT OF LABOR Employee Benefits Security Administration Prohibited Transaction Exemptions and Grant of Individual Exemptions Notice of Technical Correction Prohibited Transaction Exemptions and Grant of Individual Exemptions Involving D-11468 and D-11469, The Krispy Kreme Doughnut...

  17. Sensing a Changing Chemical Mixture Using an Electronic Nose

    NASA Technical Reports Server (NTRS)

    Duong, Tuan; Ryan, Margaret

    2008-01-01

    A method of using an electronic nose to detect an airborne mixture of known chemical compounds and measure the temporally varying concentrations of the individual compounds is undergoing development. In a typical intended application, the method would be used to monitor the air in an inhabited space (e.g., the interior of a building) for the release of solvents, toxic fumes, and other compounds that are regarded as contaminants. At the present state of development, the method affords a capability for identifying and quantitating one or two compounds that are members of a set of some number (typically of the order of a dozen) known compounds. In principle, the method could be extended to enable monitoring of more than two compounds. An electronic nose consists of an array of sensors, typically made from polymer carbon composites, the electrical resistances of which change upon exposure to a variety of chemicals. By design, each sensor is unique in its responses to these chemicals: some or all of the sensitivities of a given sensor to the various vapors differ from the corresponding sensitivities of other sensors. In general, the responses of the sensors are nonlinear functions of the concentrations of the chemicals. Hence, mathematically, the monitoring problem is to solve the set of time-dependent nonlinear equations for the sensor responses to obtain the time dependent concentrations of individual compounds. In the present developmental method, successive approximations of the solution are generated by a learning algorithm based on independent-component analysis (ICA) an established information theoretic approach for transforming a vector of observed interdependent signals into a set of signals that are as nearly statistically independent as possible.

  18. 40 CFR 180.1167 - Allyl isothiocyanate as a component of food grade oil of mustard; exemption from the requirement...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... used as a component of food grade oil of mustard, in or on all raw agricultural commodities, when... food grade oil of mustard; exemption from the requirement of a tolerance. 180.1167 Section 180.1167... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1167 Allyl isothiocyanate...

  19. CWIS Experiment On Board REXUS-16 Sounding Rocket: Investigation of the Chemical Wave in Binary Mixture

    NASA Astrophysics Data System (ADS)

    Tzevelecos, W.; Pugliese, A.; de Filippis, L.; Manzone, S.; Alfano, B.; Mancino, F.; Runge, W.; Desenfans, O.; Galand, Q.; Van Vaerenbergh, S.

    2015-09-01

    Chemical Wave in Soret Effect (CWIS) is an experiment launched in May 2014 on-board a REXUS sounding rocket from Esrange Space Center. The experiment was completely designed and assembled by students from different countries under an international collaboration between the Université libre de Bruxelles (ULB) and the University of Naples Federico II. This student program called REXUS/BEXUS allows students to perform experiments in space science applications under the supervision of the European Space Agency (ESA). The objective of the CWIS Team was to visualize the Chemical Wave (CW) during the transient of the Soret effect. The CW is a concentration front that rapidly propagates under thermal gradient in a liquid mixture, and which marks the beginning of the chemical separation phenomenon by thermodiffusion (the separation process is itself named Soret effect, but is usually analyzed statically). The selected mixture was a solution of Ethylene Glycol in Water and concentration variation due to thermal gradients was recorded using a modified Fizeau interferometer, with modifications designed to enlarge a very small region of the test cell using cylindrical squeezing. We recorded more than 100 images with the chemical information and in this paper work we will show the final results of the sounding rocket experiment.

  20. An experimental and detailed chemical kinetic modeling study of hydrogen and syngas mixture oxidation at elevated pressures

    DOE PAGES

    Keromnes, Alan; Metcalfe, Wayne K.; Heufer, Karl A.; ...

    2013-03-12

    The oxidation of syngas mixtures was investigated experimentally and simulated with an updated chemical kinetic model. Ignition delay times for H 2/CO/O 2/N 2/Ar mixtures have been measured using two rapid compression machines and shock tubes at pressures from 1 to 70 bar, over a temperature range of 914–2220 K and at equivalence ratios from 0.1 to 4.0. Results show a strong dependence of ignition times on temperature and pressure at the end of the compression; ignition delays decrease with increasing temperature, pressure, and equivalence ratio. The reactivity of the syngas mixtures was found to be governed by hydrogen chemistrymore » for CO concentrations lower than 50% in the fuel mixture. For higher CO concentrations, an inhibiting effect of CO was observed. Flame speeds were measured in helium for syngas mixtures with a high CO content and at elevated pressures of 5 and 10 atm using the spherically expanding flame method. A detailed chemical kinetic mechanism for hydrogen and H 2/CO (syngas) mixtures has been updated, rate constants have been adjusted to reflect new experimental information obtained at high pressures and new rate constant values recently published in the literature. Experimental results for ignition delay times and flame speeds have been compared with predictions using our newly revised chemical kinetic mechanism, and good agreement was observed. In the mechanism validation, particular emphasis is placed on predicting experimental data at high pressures (up to 70 bar) and intermediate- to high-temperature conditions, particularly important for applications in internal combustion engines and gas turbines. The reaction sequence H 2 + HO˙ 2 ↔ H˙+H 2O 2 followed by H 2O 2(+M) ↔ O˙H+O˙H(+M) was found to play a key role in hydrogen ignition under high-pressure and intermediate-temperature conditions. The rate constant for H 2+HO˙ 2 showed strong sensitivity to high-pressure ignition times and has considerable uncertainty, based on

  1. 40 CFR 180.1011 - Viable spores of the microorganism Bacillus thuringiensis Berliner; exemption from the...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1011 Viable spores of the... characteristics of the parent strain or contamination by other microorganisms. (3) Each lot of spore preparation... production is a Bacillus thuringiensis strain which does not produce β-exotoxin under standard manufacturing...

  2. Effective Strategies for Monitoring and Regulating Chemical Mixtures and Contaminants Sharing Pathways of Toxicity

    PubMed Central

    Venkatesan, Arjun K.; Halden, Rolf U.

    2015-01-01

    Traditionally, hazardous chemicals have been regulated in the U.S. on a one-by-one basis, an approach that is slow, expensive and can be inefficient, as illustrated by a decades-long succession of replacing one type of organohalogen flame retardants (OHFRs) with another one, without addressing the root cause of toxicity and associated public health threats posed. The present article expounds on the need for efficient monitoring strategies and pragmatic steps in reducing environmental pollution and adverse human health impacts. A promising approach is to combine specific bioassays with state-of-the-art chemical screening to identify chemicals and chemical mixtures sharing specific modes of action (MOAs) and pathways of toxicity (PoTs). This approach could be used to identify and regulate hazardous chemicals as classes or compound families, featuring similar biological end-points, such as endocrine disruption and mutagenicity. Opportunities and potential obstacles of implementing this approach are discussed. PMID:26343697

  3. Molecular simulations of Hugoniots of detonation product mixtures at chemical equilibrium: Microscopic calculation of the Chapman-Jouguet state

    NASA Astrophysics Data System (ADS)

    Bourasseau, Emeric; Dubois, Vincent; Desbiens, Nicolas; Maillet, Jean-Bernard

    2007-08-01

    In this work, we used simultaneously the reaction ensemble Monte Carlo (ReMC) method and the adaptive Erpenbeck equation of state (AE-EOS) method to directly calculate the thermodynamic and chemical equilibria of mixtures of detonation products on the Hugoniot curve. The ReMC method [W. R. Smith and B. Triska, J. Chem. Phys. 100, 3019 (1994)] allows us to reach the chemical equilibrium of a reacting mixture, and the AE-EOS method [J. J. Erpenbeck, Phys. Rev. A 46, 6406 (1992)] constrains the system to satisfy the Hugoniot relation. Once the Hugoniot curve of the detonation product mixture is established, the Chapman-Jouguet (CJ) state of the explosive can be determined. A NPT simulation at PCJ and TCJ is then performed in order to calculate direct thermodynamic properties and the following derivative properties of the system using a fluctuation method: calorific capacities, sound velocity, and Grüneisen coefficient. As the chemical composition fluctuates, and the number of particles is not necessarily constant in this ensemble, a fluctuation formula has been developed to take into account the fluctuations of mole number and composition. This type of calculation has been applied to several usual energetic materials: nitromethane, tetranitromethane, hexanitroethane, PETN, and RDX.

  4. Molecular simulations of Hugoniots of detonation product mixtures at chemical equilibrium: microscopic calculation of the Chapman-Jouguet state.

    PubMed

    Bourasseau, Emeric; Dubois, Vincent; Desbiens, Nicolas; Maillet, Jean-Bernard

    2007-08-28

    In this work, we used simultaneously the reaction ensemble Monte Carlo (ReMC) method and the adaptive Erpenbeck equation of state (AE-EOS) method to directly calculate the thermodynamic and chemical equilibria of mixtures of detonation products on the Hugoniot curve. The ReMC method [W. R. Smith and B. Triska, J. Chem. Phys. 100, 3019 (1994)] allows us to reach the chemical equilibrium of a reacting mixture, and the AE-EOS method [J. J. Erpenbeck, Phys. Rev. A 46, 6406 (1992)] constrains the system to satisfy the Hugoniot relation. Once the Hugoniot curve of the detonation product mixture is established, the Chapman-Jouguet (CJ) state of the explosive can be determined. A NPT simulation at P(CJ) and T(CJ) is then performed in order to calculate direct thermodynamic properties and the following derivative properties of the system using a fluctuation method: calorific capacities, sound velocity, and Gruneisen coefficient. As the chemical composition fluctuates, and the number of particles is not necessarily constant in this ensemble, a fluctuation formula has been developed to take into account the fluctuations of mole number and composition. This type of calculation has been applied to several usual energetic materials: nitromethane, tetranitromethane, hexanitroethane, PETN, and RDX.

  5. Polymer Exemption Guidance Manual for premanufacture notices for new chemicals under the Toxic Substances Control Act (TSCA)

    EPA Pesticide Factsheets

    A technical manual to accompany, but not supersede the Premanufacture Notification Exemptions; Revisions of Exemptions for Polymers; Final Rule found at 40 CFR Part 723, (60) FR 16316-16336, published Wednesday, March 29, 1995.

  6. Endocrine disrupting chemicals in mixture and obesity, diabetes and related metabolic disorders

    PubMed Central

    Le Magueresse-Battistoni, Brigitte; Labaronne, Emmanuel; Vidal, Hubert; Naville, Danielle

    2017-01-01

    Obesity and associated metabolic disorders represent a major societal challenge in health and quality of life with large psychological consequences in addition to physical disabilities. They are also one of the leading causes of morbidity and mortality. Although, different etiologic factors including excessive food intake and reduced physical activity have been well identified, they cannot explain the kinetics of epidemic evolution of obesity and diabetes with prevalence rates reaching pandemic proportions. Interestingly, convincing data have shown that environmental pollutants, specifically those endowed with endocrine disrupting activities, could contribute to the etiology of these multifactorial metabolic disorders. Within this review, we will recapitulate characteristics of endocrine disruption. We will demonstrate that metabolic disorders could originate from endocrine disruption with a particular focus on convincing data from the literature. Eventually, we will present how handling an original mouse model of chronic exposition to a mixture of pollutants allowed demonstrating that a mixture of pollutants each at doses beyond their active dose could induce substantial deleterious effects on several metabolic end-points. This proof-of-concept study, as well as other studies on mixtures of pollutants, stresses the needs for revisiting the current threshold model used in risk assessment which does not take into account potential effects of mixtures containing pollutants at environmental doses, e.g., the real life exposure. Certainly, more studies are necessary to better determine the nature of the chemicals to which humans are exposed and at which level, and their health impact. As well, research studies on substitute products are essential to identify harmless molecules. PMID:28588754

  7. 40 CFR 180.1246 - Yeast Extract Hydrolysate from Saccharomyces cerevisiae: exemption from the requirement of a...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Yeast Extract Hydrolysate from... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1246 Yeast Extract Hydrolysate from... exemption from the requirement of a tolerance for residues of the biochemical pesticide Yeast Extract...

  8. 40 CFR 180.1246 - Yeast Extract Hydrolysate from Saccharomyces cerevisiae: exemption from the requirement of a...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Yeast Extract Hydrolysate from... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1246 Yeast Extract Hydrolysate from... exemption from the requirement of a tolerance for residues of the biochemical pesticide Yeast Extract...

  9. 40 CFR 180.1246 - Yeast Extract Hydrolysate from Saccharomyces cerevisiae: exemption from the requirement of a...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Yeast Extract Hydrolysate from... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1246 Yeast Extract Hydrolysate from... exemption from the requirement of a tolerance for residues of the biochemical pesticide Yeast Extract...

  10. 40 CFR 180.1246 - Yeast Extract Hydrolysate from Saccharomyces cerevisiae: exemption from the requirement of a...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Yeast Extract Hydrolysate from... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1246 Yeast Extract Hydrolysate from... exemption from the requirement of a tolerance for residues of the biochemical pesticide Yeast Extract...

  11. 40 CFR 180.7 - Petitions proposing tolerances or exemptions for pesticide residues in or on raw agricultural...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... exemptions for pesticide residues in or on raw agricultural commodities or processed foods. 180.7 Section 180.7 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Procedural Regulations § 180.7 Petitions...

  12. 40 CFR 180.7 - Petitions proposing tolerances or exemptions for pesticide residues in or on raw agricultural...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... exemptions for pesticide residues in or on raw agricultural commodities or processed foods. 180.7 Section 180.7 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Procedural Regulations § 180.7 Petitions...

  13. 40 CFR 180.7 - Petitions proposing tolerances or exemptions for pesticide residues in or on raw agricultural...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... exemptions for pesticide residues in or on raw agricultural commodities or processed foods. 180.7 Section 180.7 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Procedural Regulations § 180.7 Petitions...

  14. Using Big Data Analytics to Address Mixtures Exposure

    EPA Science Inventory

    The assessment of chemical mixtures is a complex issue for regulators and health scientists. We propose that assessing chemical co-occurrence patterns and prevalence rates is a relatively simple yet powerful approach in characterizing environmental mixtures and mixtures exposure...

  15. Effects of biologically-active chemical mixtures on fish in a wastewater-impacted urban stream

    USGS Publications Warehouse

    Barber, L.B.; Brown, G.K.; Nettesheim, T.G.; Murphy, E.W.; Bartell, S.E.; Schoenfuss, H.L.

    2011-01-01

    Stream flow in urban aquatic ecosystems often is maintained by water-reclamation plant (WRP) effluents that contain mixtures of natural and anthropogenic chemicals that persist through the treatment processes. In effluent-impacted streams, aquatic organisms such as fish are continuously exposed to biologically-active chemicals throughout their life cycles. The North Shore Channel of the Chicago River (Chicago, Illinois) is part of an urban ecosystem in which > 80% of the annual flow consists of effluent from the North Side WRP. In this study, multiple samplings of the effluent and stream water were conducted and fish (largemouth bass and carp) were collected on 2 occasions from the North Shore Channel. Fish also were collected once from the Outer Chicago Harbor in Lake Michigan, a reference site not impacted by WRP discharges. Over 100 organic chemicals with differing behaviors and biological effects were measured, and 23 compounds were detected in all of the water samples analyzed. The most frequently detected and highest concentration (> 100 ??g/L) compounds were ethylenediaminetetraacetic acid and 4-nonylphenolmono-to-tetraethoxycarboxylic acids. Other biologically-active chemicals including bisphenol A, 4-nonylphenol, 4-nonylphenolmono-to-tetraethoxylates, 4- tert-octylphenol, and 4- tert-octylphenolmono-to-tetraethoxylates were detected at lower concentrations (< 5 ??g/L). The biogenic steroidal hormones 17??-estradiol, estrone, testosterone, 4-androstene-3,17-dione, and cis-androsterone were detected at even lower concentrations (< 0.005 ??g/L). There were slight differences in concentrations between the North Side WRP effluent and the North Shore Channel, indicating minimal in-stream attenuation. Fish populations are continuously exposed to mixtures of biologically-active chemicals because of the relative persistency of the chemicals with respect to stream hydraulic residence time, and the lack of a fresh water source for dilution. The majority of male fish

  16. Evaluation of the COSHH Essentials model with a mixture of organic chemicals at a medium-sized paint producer.

    PubMed

    Lee, Eun Gyung; Slaven, James; Bowen, Russell B; Harper, Martin

    2011-01-01

    The Control of Substances Hazardous to Health (COSHH) Essentials model was evaluated using full-shift exposure measurements of five chemical components in a mixture [acetone, ethylbenzene, methyl ethyl ketone, toluene, and xylenes] at a medium-sized plant producing paint materials. Two tasks, batch-making and bucket-washing, were examined. Varying levels of control were already established in both tasks and the average exposures of individual chemicals were considerably lower than the regulatory and advisory 8-h standards. The average exposure fractions using the additive mixture formula were also less than unity (batch-making: 0.25, bucket-washing: 0.56) indicating the mixture of chemicals did not exceed the combined occupational exposure limit (OEL). The paper version of the COSHH Essentials model was used to calculate a predicted exposure range (PER) for each chemical according to different levels of control. The estimated PERs of the tested chemicals for both tasks did not show consistent agreement with exposure measurements when the comparison was made for each control method and this is believed to be because of the considerably different volatilities of the chemicals. Given the combination of health hazard and exposure potential components, the COSHH Essentials model recommended a control approach 'special advice' for both tasks, based on the potential reproductive hazard ascribed to toluene. This would not have been the same conclusion if some other chemical had been substituted (for example styrene, which has the same threshold limit value as toluene). Nevertheless, it was special advice, which had led to the combination of hygienic procedures in place at this plant. The probability of the combined exposure fractions exceeding unity was 0.0002 for the batch-making task indicating that the employees performing this task were most likely well protected below the OELs. Although the employees involved in the bucket-washing task had greater potential to exceed

  17. 40 CFR 91.1006 - Manufacturer-owned exemption and precertification exemption.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Exclusion and Exemption of Marine SI Engines § 91.1006 Manufacturer-owned exemption and precertification exemption. (a... “Emission Control Information;” (B) Full corporate name and trademark of manufacturer; (C) Engine...

  18. Allium-test as a tool for toxicity testing of environmental radioactive-chemical mixtures

    NASA Astrophysics Data System (ADS)

    Oudalova, A. A.; Geras'kin, S. A.; Dikareva, N. S.; Pyatkova, S. V.

    2017-01-01

    Bioassay-based approaches have been propagated to assess toxicity of unknown mixtures of environmental contaminants, but it was rarely applied in cases of chemicals with radionuclides combinations. Two Allium-test studies were performed to assess environmental impact from potential sources of combined radioactive-chemical pollution. Study sites were located at nuclear waste storage facilities in European and in Far-Eastern parts of Russia. As environmental media under impact, waters from monitor wells and nearby water bodies were tested. Concentrations of some chemicals and radionuclides in the samples collected enhanced the permitted limits. Cytogenetic and cytotoxic effects were used as biological endpoints, namely, frequency and spectrum of chromosome aberrations and mitotic abnormalities in anatelophase cells as well as mitotic activity in Allium root tips. Sample points were revealed where waters have an enhanced mutagenic potential. The findings obtained could be used to optimize monitoring system and advance decision making on management and rehabilitation of industrial sites. The Allium-test could be recommended and applied as an effective tool for toxicity testing in case of combined contamination of environmental compartments with radionuclides and chemical compounds.

  19. 40 CFR 180.1243 - Bacillus subtilis var. amyloliquefaciens strain FZB24; exemption from the requirement of a...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Bacillus subtilis var... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1243 Bacillus subtilis... the requirement of a tolerance for residues of the Bacillus subtilis var. amyloliquefaciens strain...

  20. Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling

    PubMed Central

    Mao, Bing; Mao, Rong; Zeng, De-Hui

    2017-01-01

    Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N mineralization and soil respiration, four single litter species and their mixtures consisting of all possible 2-, 3- and 4-species combinations were added to soils, respectively. In most instances, species mixing produced synergistic non-additive effects on soil microbial biomass N and soil respiration, but antagonistic non-additive effects on net N mineralization. Species composition rather than species richness explained the non-additive effects of species mixing on soil microbial biomass N and net N mineralization, due to the interspecific differences in litter chemical composition. Both litter species composition and richness explained non-additive soil respiration responses to mixed-species litter, while litter chemical diversity and chemical composition did not. Our study indicated that litter mixtures promoted soil microbial biomass N and soil respiration, and inhibited net N mineralization. Soil N related processes rather than soil respiration were partly explained by litter chemical composition and chemical diversity, highlighting the importance of functional diversity of litter on soil N cycling. PMID:28686660

  1. Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling.

    PubMed

    Mao, Bing; Mao, Rong; Zeng, De-Hui

    2017-01-01

    Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N mineralization and soil respiration, four single litter species and their mixtures consisting of all possible 2-, 3- and 4-species combinations were added to soils, respectively. In most instances, species mixing produced synergistic non-additive effects on soil microbial biomass N and soil respiration, but antagonistic non-additive effects on net N mineralization. Species composition rather than species richness explained the non-additive effects of species mixing on soil microbial biomass N and net N mineralization, due to the interspecific differences in litter chemical composition. Both litter species composition and richness explained non-additive soil respiration responses to mixed-species litter, while litter chemical diversity and chemical composition did not. Our study indicated that litter mixtures promoted soil microbial biomass N and soil respiration, and inhibited net N mineralization. Soil N related processes rather than soil respiration were partly explained by litter chemical composition and chemical diversity, highlighting the importance of functional diversity of litter on soil N cycling.

  2. 40 CFR 180.950 - Tolerance exemptions for minimal risk active and inert ingredients.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... inert or an active ingredient in a pesticide chemical formulation, including antimicrobial pesticide..., cloves, and red pepper. (iii) Herbs such as basil, anise, or fenugreek. (2) Excluded from the term...

  3. 40 CFR 180.950 - Tolerance exemptions for minimal risk active and inert ingredients.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... inert or an active ingredient in a pesticide chemical formulation, including antimicrobial pesticide..., cloves, and red pepper. (iii) Herbs such as basil, anise, or fenugreek. (2) Excluded from the term...

  4. 40 CFR 180.950 - Tolerance exemptions for minimal risk active and inert ingredients.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... inert or an active ingredient in a pesticide chemical formulation, including antimicrobial pesticide..., cloves, and red pepper. (iii) Herbs such as basil, anise, or fenugreek. (2) Excluded from the term...

  5. 40 CFR 180.950 - Tolerance exemptions for minimal risk active and inert ingredients.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... inert or an active ingredient in a pesticide chemical formulation, including antimicrobial pesticide..., cloves, and red pepper. (iii) Herbs such as basil, anise, or fenugreek. (2) Excluded from the term...

  6. 40 CFR 180.1130 - N-(n-octyl)-2-pyrrolidone and N-(n-dodecyl)-2-pyrrolidone; exemptions from the requirement of a...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false N-(n-octyl)-2-pyrrolidone and N-(n... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1130 N-(n-octyl)-2-pyrrolidone and N-(n-dodecyl)-2-pyrrolidone; exemptions from the requirement of a tolerance. N-(n-octyl)-2...

  7. 40 CFR 180.1130 - N-(n-octyl)-2-pyrrolidone and N-(n-dodecyl)-2-pyrrolidone; exemptions from the requirement of a...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false N-(n-octyl)-2-pyrrolidone and N-(n... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1130 N-(n-octyl)-2-pyrrolidone and N-(n-dodecyl)-2-pyrrolidone; exemptions from the requirement of a tolerance. N-(n-octyl)-2...

  8. 40 CFR 180.1279 - Zucchini yellow mosaic virus-weak strain; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Zucchini yellow mosaic virus-weak strain; exemption from the requirement of a tolerance. 180.1279 Section 180.1279 Protection of... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1279 Zucchini yellow mosaic virus—weak...

  9. 40 CFR 180.1279 - Zucchini yellow mosaic virus-weak strain; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Zucchini yellow mosaic virus-weak strain; exemption from the requirement of a tolerance. 180.1279 Section 180.1279 Protection of... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1279 Zucchini yellow mosaic virus—weak...

  10. 40 CFR 180.1279 - Zucchini yellow mosaic virus-weak strain; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Zucchini yellow mosaic virus-weak strain; exemption from the requirement of a tolerance. 180.1279 Section 180.1279 Protection of... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1279 Zucchini yellow mosaic virus—weak...

  11. 40 CFR 180.1279 - Zucchini yellow mosaic virus-weak strain; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Zucchini yellow mosaic virus-weak strain; exemption from the requirement of a tolerance. 180.1279 Section 180.1279 Protection of... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1279 Zucchini yellow mosaic virus—weak...

  12. 40 CFR 180.1279 - Zucchini yellow mosaic virus-weak strain; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Zucchini yellow mosaic virus-weak strain; exemption from the requirement of a tolerance. 180.1279 Section 180.1279 Protection of... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1279 Zucchini yellow mosaic virus—weak...

  13. Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.

    PubMed

    Goodson, William H; Lowe, Leroy; Carpenter, David O; Gilbertson, Michael; Manaf Ali, Abdul; Lopez de Cerain Salsamendi, Adela; Lasfar, Ahmed; Carnero, Amancio; Azqueta, Amaya; Amedei, Amedeo; Charles, Amelia K; Collins, Andrew R; Ward, Andrew; Salzberg, Anna C; Colacci, Annamaria; Olsen, Ann-Karin; Berg, Arthur; Barclay, Barry J; Zhou, Binhua P; Blanco-Aparicio, Carmen; Baglole, Carolyn J; Dong, Chenfang; Mondello, Chiara; Hsu, Chia-Wen; Naus, Christian C; Yedjou, Clement; Curran, Colleen S; Laird, Dale W; Koch, Daniel C; Carlin, Danielle J; Felsher, Dean W; Roy, Debasish; Brown, Dustin G; Ratovitski, Edward; Ryan, Elizabeth P; Corsini, Emanuela; Rojas, Emilio; Moon, Eun-Yi; Laconi, Ezio; Marongiu, Fabio; Al-Mulla, Fahd; Chiaradonna, Ferdinando; Darroudi, Firouz; Martin, Francis L; Van Schooten, Frederik J; Goldberg, Gary S; Wagemaker, Gerard; Nangami, Gladys N; Calaf, Gloria M; Williams, Graeme; Wolf, Gregory T; Koppen, Gudrun; Brunborg, Gunnar; Lyerly, H Kim; Krishnan, Harini; Ab Hamid, Hasiah; Yasaei, Hemad; Sone, Hideko; Kondoh, Hiroshi; Salem, Hosni K; Hsu, Hsue-Yin; Park, Hyun Ho; Koturbash, Igor; Miousse, Isabelle R; Scovassi, A Ivana; Klaunig, James E; Vondráček, Jan; Raju, Jayadev; Roman, Jesse; Wise, John Pierce; Whitfield, Jonathan R; Woodrick, Jordan; Christopher, Joseph A; Ochieng, Josiah; Martinez-Leal, Juan Fernando; Weisz, Judith; Kravchenko, Julia; Sun, Jun; Prudhomme, Kalan R; Narayanan, Kannan Badri; Cohen-Solal, Karine A; Moorwood, Kim; Gonzalez, Laetitia; Soucek, Laura; Jian, Le; D'Abronzo, Leandro S; Lin, Liang-Tzung; Li, Lin; Gulliver, Linda; McCawley, Lisa J; Memeo, Lorenzo; Vermeulen, Louis; Leyns, Luc; Zhang, Luoping; Valverde, Mahara; Khatami, Mahin; Romano, Maria Fiammetta; Chapellier, Marion; Williams, Marc A; Wade, Mark; Manjili, Masoud H; Lleonart, Matilde E; Xia, Menghang; Gonzalez, Michael J; Karamouzis, Michalis V; Kirsch-Volders, Micheline; Vaccari, Monica; Kuemmerle, Nancy B; Singh, Neetu; Cruickshanks, Nichola; Kleinstreuer, Nicole; van Larebeke, Nik; Ahmed, Nuzhat; Ogunkua, Olugbemiga; Krishnakumar, P K; Vadgama, Pankaj; Marignani, Paola A; Ghosh, Paramita M; Ostrosky-Wegman, Patricia; Thompson, Patricia A; Dent, Paul; Heneberg, Petr; Darbre, Philippa; Sing Leung, Po; Nangia-Makker, Pratima; Cheng, Qiang Shawn; Robey, R Brooks; Al-Temaimi, Rabeah; Roy, Rabindra; Andrade-Vieira, Rafaela; Sinha, Ranjeet K; Mehta, Rekha; Vento, Renza; Di Fiore, Riccardo; Ponce-Cusi, Richard; Dornetshuber-Fleiss, Rita; Nahta, Rita; Castellino, Robert C; Palorini, Roberta; Abd Hamid, Roslida; Langie, Sabine A S; Eltom, Sakina E; Brooks, Samira A; Ryeom, Sandra; Wise, Sandra S; Bay, Sarah N; Harris, Shelley A; Papagerakis, Silvana; Romano, Simona; Pavanello, Sofia; Eriksson, Staffan; Forte, Stefano; Casey, Stephanie C; Luanpitpong, Sudjit; Lee, Tae-Jin; Otsuki, Takemi; Chen, Tao; Massfelder, Thierry; Sanderson, Thomas; Guarnieri, Tiziana; Hultman, Tove; Dormoy, Valérian; Odero-Marah, Valerie; Sabbisetti, Venkata; Maguer-Satta, Veronique; Rathmell, W Kimryn; Engström, Wilhelm; Decker, William K; Bisson, William H; Rojanasakul, Yon; Luqmani, Yunus; Chen, Zhenbang; Hu, Zhiwei

    2015-06-01

    Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology. © The Author 2015. Published by Oxford University Press.

  14. Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead

    PubMed Central

    Goodson, William H.; Lowe, Leroy; Carpenter, David O.; Gilbertson, Michael; Manaf Ali, Abdul; Lopez de Cerain Salsamendi, Adela; Lasfar, Ahmed; Carnero, Amancio; Azqueta, Amaya; Amedei, Amedeo; Charles, Amelia K.; Collins, Andrew R.; Ward, Andrew; Salzberg, Anna C.; Colacci, Anna Maria; Olsen, Ann-Karin; Berg, Arthur; Barclay, Barry J.; Zhou, Binhua P.; Blanco-Aparicio, Carmen; Baglole, Carolyn J.; Dong, Chenfang; Mondello, Chiara; Hsu, Chia-Wen; Naus, Christian C.; Yedjou, Clement; Curran, Colleen S.; Laird, Dale W.; Koch, Daniel C.; Carlin, Danielle J.; Felsher, Dean W.; Roy, Debasish; Brown, Dustin G.; Ratovitski, Edward; Ryan, Elizabeth P.; Corsini, Emanuela; Rojas, Emilio; Moon, Eun-Yi; Laconi, Ezio; Marongiu, Fabio; Al-Mulla, Fahd; Chiaradonna, Ferdinando; Darroudi, Firouz; Martin, Francis L.; Van Schooten, Frederik J.; Goldberg, Gary S.; Wagemaker, Gerard; Nangami, Gladys N.; Calaf, Gloria M.; Williams, Graeme P.; Wolf, Gregory T.; Koppen, Gudrun; Brunborg, Gunnar; Lyerly, H. Kim; Krishnan, Harini; Ab Hamid, Hasiah; Yasaei, Hemad; Sone, Hideko; Kondoh, Hiroshi; Salem, Hosni K.; Hsu, Hsue-Yin; Park, Hyun Ho; Koturbash, Igor; Miousse, Isabelle R.; Scovassi, A.Ivana; Klaunig, James E.; Vondráček, Jan; Raju, Jayadev; Roman, Jesse; Wise, John Pierce; Whitfield, Jonathan R.; Woodrick, Jordan; Christopher, Joseph A.; Ochieng, Josiah; Martinez-Leal, Juan Fernando; Weisz, Judith; Kravchenko, Julia; Sun, Jun; Prudhomme, Kalan R.; Narayanan, Kannan Badri; Cohen-Solal, Karine A.; Moorwood, Kim; Gonzalez, Laetitia; Soucek, Laura; Jian, Le; D’Abronzo, Leandro S.; Lin, Liang-Tzung; Li, Lin; Gulliver, Linda; McCawley, Lisa J.; Memeo, Lorenzo; Vermeulen, Louis; Leyns, Luc; Zhang, Luoping; Valverde, Mahara; Khatami, Mahin; Romano, Maria Fiammetta; Chapellier, Marion; Williams, Marc A.; Wade, Mark; Manjili, Masoud H.; Lleonart, Matilde E.; Xia, Menghang; Gonzalez Guzman, Michael J.; Karamouzis, Michalis V.; Kirsch-Volders, Micheline; Vaccari, Monica; Kuemmerle, Nancy B.; Singh, Neetu; Cruickshanks, Nichola; Kleinstreuer, Nicole; van Larebeke, Nik; Ahmed, Nuzhat; Ogunkua, Olugbemiga; Krishnakumar, P.K.; Vadgama, Pankaj; Marignani, Paola A.; Ghosh, Paramita M.; Ostrosky-Wegman, Patricia; Thompson, Patricia A.; Dent, Paul; Heneberg, Petr; Darbre, Philippa; Leung, Po Sing; Nangia-Makker, Pratima; Cheng, Qiang (Shawn); Robey, R.Brooks; Al-Temaimi, Rabeah; Roy, Rabindra; Andrade-Vieira, Rafaela; Sinha, Ranjeet K.; Mehta, Rekha; Vento, Renza; Di Fiore, Riccardo; Ponce-Cusi, Richard; Dornetshuber-Fleiss, Rita; Nahta, Rita; Castellino, Robert C.; Palorini, Roberta; Hamid, Roslida A.; Langie, Sabine A.S.; Eltom, Sakina E.; Brooks, Samira A.; Ryeom, Sandra; Wise, Sandra S.; Bay, Sarah N.; Harris, Shelley A.; Papagerakis, Silvana; Romano, Simona; Pavanello, Sofia; Eriksson, Staffan; Forte, Stefano; Casey, Stephanie C.; Luanpitpong, Sudjit; Lee, Tae-Jin; Otsuki, Takemi; Chen, Tao; Massfelder, Thierry; Sanderson, Thomas; Guarnieri, Tiziana; Hultman, Tove; Dormoy, Valérian; Odero-Marah, Valerie; Sabbisetti, Venkata; Maguer-Satta, Veronique; Rathmell, W.Kimryn; Engström, Wilhelm; Decker, William K.; Bisson, William H.; Rojanasakul, Yon; Luqmani, Yunus; Chen, Zhenbang; Hu, Zhiwei

    2015-01-01

    Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety ‘Mode of Action’ framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology. PMID:26106142

  15. 7 CFR 1210.516 - Exemption for organic watermelons.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    .... (a) A producer who produces only products that are eligible to be labeled as 100 percent organic... include lack of demand for organic products, isolated use of antibiotics for humane purposes, chemical or... 7 Agriculture 10 2011-01-01 2011-01-01 false Exemption for organic watermelons. 1210.516 Section...

  16. Hazard and risk assessment of chemical mixtures using the toxic equivalency factor approach.

    PubMed

    Safe, S H

    1998-08-01

    There is considerable public, regulatory, and scientific concern regarding human exposure to endocrine-disrupting chemicals, which include compounds that directly modulate steroid hormone receptor pathways (estrogens, antiestrogens, androgens, antiandrogens) and aryl hydrocarbon receptor (AhR) agonists, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds. Based on quantitative structure-activity relationships for both AhR and estrogen receptor (ER) agonists, the relative potency (RP) of individual compounds relative to a standard (e.g. TCDD and 17-beta-estradiol) have been determined for several receptor-mediated responses. Therefore, the TCDD or estrogenic equivalent (TEQ or EQ, respectively) of a mixture is defined as TEQ = sigma[T(i)]xRP(i)or EQ=sigma[E(i)]xRP(i), where T(i) and E(i) are concentrations of individual AhR or ER agonists in any mixture. This approach for risk assessment of endocrine-disrupting mixtures assumes that for each endocrine response pathway, the effects of individual compounds are essentially additive. This paper will critically examine the utility of the TEQ/EQ approach for risk assessment, the validity of the assumptions used for this approach, and the problems associated with comparing low dose exposures to xeno and natural (dietary) endocrine disruptors.

  17. Probabilistic Human Health Risk Assessment of Chemical Mixtures: Hydro-Toxicological Interactions and Controlling Factors

    NASA Astrophysics Data System (ADS)

    Henri, C.; Fernandez-Garcia, D.; de Barros, F.

    2014-12-01

    Improper disposals of hazardous wastes in most industrial countries give rise to severe groundwater contamination problems that can lead to adverse health effects in humans. Therefore risk assessment methods play an important role in population protection by (1) quantifying the impact on human health of an aquifer contamination and (2) aiding the decision making process of to better manage our groundwater resources. Many reactive components such as chlorinated solvent or nitrate potentially experience attenuation processes under common geochemical conditions. Based on this, monitored natural attenuation has become nowadays an attractive remediation solution. However, in some cases, intermediate degradation products can constitute noxious chemical compounds before reaching a harmless chemical form. In these cases, the joint effect of advection-dispersion transport and the species-dependent kinetic reactions and toxicity will dictate the relative importance of the degradation byproducts to the total risk. This renders the interpretation of risk a non-trivial task. In this presentation, we quantify, through a probabilistic framework, the human health risk posed by a chemical mixture in a heterogeneous aquifer. This work focuses on a Perchloroethylene contamination problem followed by the first-order production/biodegradation of its daughter species Trichloroethylene, Dichloroethylene and Vinyl Chlorine that is known to be highly toxic. Uncertainty on the hydraulic conductivity field is considered through a Monte Carlo scheme. A comparative description of human health risk metrics as a function of aquifer heterogeneity and contaminant injection mode is provided by means of a spatial characterization of the lower-order statistical moments and empirical probability density functions of both individual and total risks. Interestingly, we show that the human health risk of a chemical mixture is mainly controlled by a modified Damköhler number that express the joint effect

  18. 77 FR 74116 - Extension of Tolerances for Emergency Exemptions (Multiple Chemicals)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-13

    .../text/text-idx?&c=ecfr&tpl=/ecfrbrowse/Title40/40tab_02.tpl . C. How can I file an objection or hearing... Management and Budget (OMB) has exempted these types of actions from review under Executive Order 12866.... 601 et seq.), do not apply. This final rule directly regulates growers, food processors, food handlers...

  19. Evaluation of the COSHH Essentials Model with a Mixture of Organic Chemicals at a Medium-Sized Paint Producer

    PubMed Central

    Lee, Eun Gyung; Slaven, James; Bowen, Russell B.; Harper, Martin

    2011-01-01

    The Control of Substances Hazardous to Health (COSHH) Essentials model was evaluated using full-shift exposure measurements of five chemical components in a mixture [acetone, ethylbenzene, methyl ethyl ketone, toluene, and xylenes] at a medium-sized plant producing paint materials. Two tasks, batch-making and bucket-washing, were examined. Varying levels of control were already established in both tasks and the average exposures of individual chemicals were considerably lower than the regulatory and advisory 8-h standards. The average exposure fractions using the additive mixture formula were also less than unity (batch-making: 0.25, bucket-washing: 0.56) indicating the mixture of chemicals did not exceed the combined occupational exposure limit (OEL). The paper version of the COSHH Essentials model was used to calculate a predicted exposure range (PER) for each chemical according to different levels of control. The estimated PERs of the tested chemicals for both tasks did not show consistent agreement with exposure measurements when the comparison was made for each control method and this is believed to be because of the considerably different volatilities of the chemicals. Given the combination of health hazard and exposure potential components, the COSHH Essentials model recommended a control approach ‘special advice’ for both tasks, based on the potential reproductive hazard ascribed to toluene. This would not have been the same conclusion if some other chemical had been substituted (for example styrene, which has the same threshold limit value as toluene). Nevertheless, it was special advice, which had led to the combination of hygienic procedures in place at this plant. The probability of the combined exposure fractions exceeding unity was 0.0002 for the batch-making task indicating that the employees performing this task were most likely well protected below the OELs. Although the employees involved in the bucket-washing task had greater potential to

  20. Assessment of Weighted Quantile Sum Regression for Modeling Chemical Mixtures and Cancer Risk

    PubMed Central

    Czarnota, Jenna; Gennings, Chris; Wheeler, David C

    2015-01-01

    In evaluation of cancer risk related to environmental chemical exposures, the effect of many chemicals on disease is ultimately of interest. However, because of potentially strong correlations among chemicals that occur together, traditional regression methods suffer from collinearity effects, including regression coefficient sign reversal and variance inflation. In addition, penalized regression methods designed to remediate collinearity may have limitations in selecting the truly bad actors among many correlated components. The recently proposed method of weighted quantile sum (WQS) regression attempts to overcome these problems by estimating a body burden index, which identifies important chemicals in a mixture of correlated environmental chemicals. Our focus was on assessing through simulation studies the accuracy of WQS regression in detecting subsets of chemicals associated with health outcomes (binary and continuous) in site-specific analyses and in non-site-specific analyses. We also evaluated the performance of the penalized regression methods of lasso, adaptive lasso, and elastic net in correctly classifying chemicals as bad actors or unrelated to the outcome. We based the simulation study on data from the National Cancer Institute Surveillance Epidemiology and End Results Program (NCI-SEER) case–control study of non-Hodgkin lymphoma (NHL) to achieve realistic exposure situations. Our results showed that WQS regression had good sensitivity and specificity across a variety of conditions considered in this study. The shrinkage methods had a tendency to incorrectly identify a large number of components, especially in the case of strong association with the outcome. PMID:26005323

  1. Assessment of weighted quantile sum regression for modeling chemical mixtures and cancer risk.

    PubMed

    Czarnota, Jenna; Gennings, Chris; Wheeler, David C

    2015-01-01

    In evaluation of cancer risk related to environmental chemical exposures, the effect of many chemicals on disease is ultimately of interest. However, because of potentially strong correlations among chemicals that occur together, traditional regression methods suffer from collinearity effects, including regression coefficient sign reversal and variance inflation. In addition, penalized regression methods designed to remediate collinearity may have limitations in selecting the truly bad actors among many correlated components. The recently proposed method of weighted quantile sum (WQS) regression attempts to overcome these problems by estimating a body burden index, which identifies important chemicals in a mixture of correlated environmental chemicals. Our focus was on assessing through simulation studies the accuracy of WQS regression in detecting subsets of chemicals associated with health outcomes (binary and continuous) in site-specific analyses and in non-site-specific analyses. We also evaluated the performance of the penalized regression methods of lasso, adaptive lasso, and elastic net in correctly classifying chemicals as bad actors or unrelated to the outcome. We based the simulation study on data from the National Cancer Institute Surveillance Epidemiology and End Results Program (NCI-SEER) case-control study of non-Hodgkin lymphoma (NHL) to achieve realistic exposure situations. Our results showed that WQS regression had good sensitivity and specificity across a variety of conditions considered in this study. The shrinkage methods had a tendency to incorrectly identify a large number of components, especially in the case of strong association with the outcome.

  2. 40 CFR 180.1043 - Gossyplure; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... requirement of a tolerance in or on the raw agricultural commodity cotton, undelinted seed when applied to...

  3. 40 CFR 180.1043 - Gossyplure; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... requirement of a tolerance in or on the raw agricultural commodity cotton, undelinted seed when applied to...

  4. Viscous-shock-layer solutions for turbulent flow of radiating gas mixtures in chemical equilibrium

    NASA Technical Reports Server (NTRS)

    Anderson, E. C.; Moss, J. N.

    1975-01-01

    The viscous-shock-layer equations for hypersonic laminar and turbulent flows of radiating or nonradiating gas mixtures in chemical equilibrium are presented for two-dimensional and axially-symmetric flow fields. Solutions were obtained using an implicit finite-difference scheme and results are presented for hypersonic flow over spherically-blunted cone configurations at freestream conditions representative of entry into the atmosphere of Venus. These data are compared with solutions obtained using other methods of analysis.

  5. Viscous shock layer solutions for turbulent flow of radiating gas mixtures in chemical equilibrium

    NASA Technical Reports Server (NTRS)

    Anderson, E. C.; Moss, J. N.

    1975-01-01

    The viscous shock layer equations for hypersonic laminar and turbulent flows of radiating or nonradiating gas mixtures in chemical equilibrium are presented for two-dimensional and axially symmetric flow fields. Solutions are obtained using an implicit finite difference scheme and results are presented for hypersonic flow over spherically blunted cone configurations at free stream conditions representative of entry into the atmosphere of Venus. These data are compared with solutions obtained using other methods of analysis.

  6. Emergence of life from multicomponent mixtures of chemicals: the case for experiments with cycling physicochemical gradients.

    PubMed

    Spitzer, Jan

    2013-04-01

    The emergence of life from planetary multicomponent mixtures of chemicals is arguably the most complicated and least understood natural phenomenon. The fact that living cells are non-equilibrium systems suggests that life can emerge only from non-equilibrium chemical systems. From an astrobiological standpoint, non-equilibrium chemical systems arise naturally when solar irradiation strikes rotating surfaces of habitable planets: the resulting cycling physicochemical gradients persistently drive planetary chemistries toward "embryonic" living systems and an eventual emergence of life. To better understand the factors that lead to the emergence of life, I argue for cycling non-equilibrium experiments with multicomponent chemical systems designed to represent the evolving chemistry of Hadean Earth ("prebiotic soups"). Specifically, I suggest experimentation with chemical engineering simulators of Hadean Earth to observe and analyze (i) the appearances and phase separations of surface active and polymeric materials as precursors of the first "cell envelopes" (membranes) and (ii) the accumulations, commingling, and co-reactivity of chemicals from atmospheric, oceanic, and terrestrial locations.

  7. 21 CFR 1308.35 - Exemption of certain cannabis plant material, and products made therefrom, that contain...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... means either: (i) Ingested orally or (ii) Applied by any means such that THC enters the human body. (4... human consumption, has been exempted by the Administrator from the application of the Act and this... for human consumption. (2) The term animal feed mixture means sterilized cannabis seeds mixed with...

  8. 21 CFR 1308.35 - Exemption of certain cannabis plant material, and products made therefrom, that contain...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... means either: (i) Ingested orally or (ii) Applied by any means such that THC enters the human body. (4... human consumption, has been exempted by the Administrator from the application of the Act and this... for human consumption. (2) The term animal feed mixture means sterilized cannabis seeds mixed with...

  9. Chemical Discrimination in Turbulent Gas Mixtures with MOX Sensors Validated by Gas Chromatography-Mass Spectrometry

    PubMed Central

    Fonollosa, Jordi; Rodríguez-Luján, Irene; Trincavelli, Marco; Vergara, Alexander; Huerta, Ramón

    2014-01-01

    Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. However, such a kind of experimental setup does not reproduce the gas concentration fluctuations observed in natural environments and destroys the spatio-temporal information contained in gas plumes. Aiming at reproducing more realistic environments, we utilize a wind tunnel with two independent gas sources that get naturally mixed along a turbulent flow. For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. Moreover, the ground truth of gas concentrations at the sensor location was estimated by means of gas chromatography-mass spectrometry. We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance. PMID:25325339

  10. Chemical discrimination in turbulent gas mixtures with MOX sensors validated by gas chromatography-mass spectrometry.

    PubMed

    Fonollosa, Jordi; Rodríguez-Luján, Irene; Trincavelli, Marco; Vergara, Alexander; Huerta, Ramón

    2014-10-16

    Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. However, such a kind of experimental setup does not reproduce the gas concentration fluctuations observed in natural environments and destroys the spatio-temporal information contained in gas plumes. Aiming at reproducing more realistic environments, we utilize a wind tunnel with two independent gas sources that get naturally mixed along a turbulent flow. For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. Moreover, the ground truth of gas concentrations at the sensor location was estimated by means of gas chromatography-mass spectrometry. We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance.

  11. 75 FR 4295 - Premanufacture Notification Exemption for Polymers; Amendment of Polymer Exemption Rule to...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... Premanufacture Notification Exemption for Polymers; Amendment of Polymer Exemption Rule to Exclude Certain Perfluorinated Polymers AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is amending the polymer exemption rule, which provides an exemption from the premanufacture notification (PMN...

  12. Toward a conceptual approach for assessing risks from chemical mixtures and other stressors to coastal ecosystem services.

    PubMed

    Syberg, Kristian; Backhaus, Thomas; Banta, Gary; Bruce, Peter; Gustavsson, Mikael; Munns, Wayne R; Rämö, Robert; Selck, Henriette; Gunnarsson, Jonas S

    2017-03-01

    Growth of human populations and increased human activity, particularly in coastal areas, increase pressure on coastal ecosystems and the ecosystem services (ES) they provide. As a means toward being able to assess the impact of multiple stressors on ES, in the present study we propose an 8-step conceptual approach for assessing effects of chemical mixtures and other stressors on ES in coastal areas: step A, identify the relevant problems and policy aims; step B, identify temporal and spatial boundaries; step C, identify relevant ES; step D, identify relevant stressors (e.g., chemicals); step E, translate impacts into ES units; step F, assess cumulative risk in ES units; step G, rank stressors based on their contribution to adverse effects on ES; and step H, implement regulation and management as appropriate and necessary. Two illustrative case studies (Swedish coastal waters and a coastal lagoon in Costa Rica) are provided; one focuses on chemicals that affect human food supply and the other addresses pesticide runoff and trade-offs among ES. The 2 cases are used to highlight challenges of such risk assessments, including use of standardized versus ES-relevant test species, data completeness, and trade-offs among ES. Lessons learned from the 2 case studies are discussed in relation to environmental risk assessment and management of chemical mixtures. Integr Environ Assess Manag 2017;13:376-386. © 2016 SETAC. © 2016 SETAC.

  13. 75 FR 77634 - Approval of Test Marketing Exemptions for Certain New Chemicals

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-13

    ... ENVIRONMENTAL PROTECTION AGENCY [EPA-HQ-OPPT-2010-0990; FRL-8857-3] Approval of Test Marketing...: This notice announces EPA's approval of applications for test marketing exemptions (TMEs) under section... test marketing conditions are described in the TME applications and in this notice. DATES: Approval of...

  14. COMPARISON OF SORPTION ENERGTICS FOR HYDROPHOBIC ORGANIC CHEMICALS BY SYNTHETIC AND NATURAL SORBENTS FROM METHANOL/WATER SOLVENT MIXTURES

    EPA Science Inventory

    Reversed-phase liquid chromatography (RPLC) was used to investigate the thermodynamics and mechanisms of hydrophobic organic chemical (HOC) retention from methanol/water solvent mixtures. The enthalpy-entropy compensation model was used to infer that the hydro- phobic sorptive me...

  15. Juvenile Male Rats Exposed to a Low-Dose Mixture of Twenty-Seven Environmental Chemicals Display Adverse Health Effects

    PubMed Central

    Svingen, Terje; Mandrup, Karen; Skov, Kasper; Pedersen, Mikael; Frederiksen, Hanne; Frandsen, Henrik Lauritz; Vinggaard, Anne Marie

    2016-01-01

    Humans are exposed to a large number of environmental chemicals in their daily life, many of which are readily detectable in blood or urine. It remains uncertain if these chemicals can cause adverse health effects when present together at low doses. In this study we have tested whether a mixture of 27 chemicals administered orally to juvenile male rats for three months could leave a pathophysiological footprint. The mixture contained metals, perfluorinated compounds, PCB, dioxins, pesticides, heterocyclic amines, phthalate, PAHs and others, with a combined dose of 0.16 (Low dose), 0.47 (Mid dose) or 1.6 (High dose) mg/kg bw/day. The lowest dose was designed with the aim of obtaining plasma or urine concentrations in rats at levels approaching those observed in humans. Some single congeners were administered at doses representative of combined doses for chemical groups. With this baseline, we found effects on weight, histology and gene expression in the liver, as well as changes to the blood plasma metabolome in all exposure groups, including low-dose. Additional adverse effects were observed in the higher dosed groups, including enlarged kidneys and alterations to the metabolome. No significant effects on reproductive parameters were observed. PMID:27598887

  16. 40 CFR 180.1157 - Cytokinins; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... extract of seaweed meal and kinetin) in or on all food commodities when used as plant regulators on plants...

  17. 40 CFR 180.1157 - Cytokinins; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... extract of seaweed meal and kinetin) in or on all food commodities when used as plant regulators on plants...

  18. 40 CFR 180.1157 - Cytokinins; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... extract of seaweed meal and kinetin) in or on all food commodities when used as plant regulators on plants...

  19. 40 CFR 180.1157 - Cytokinins; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... extract of seaweed meal and kinetin) in or on all food commodities when used as plant regulators on plants...

  20. 40 CFR 180.1157 - Cytokinins; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... extract of seaweed meal and kinetin) in or on all food commodities when used as plant regulators on plants...

  1. First-Principles Study of Chemical Mixtures of CaCl2 and MgCl2 Hydrates for Optimized Seasonal Heat Storage

    PubMed Central

    2017-01-01

    Chloride-based salt hydrates form a promising class of thermochemical materials (TCMs), having high storage capacity and fast kinetics. In the charging cycles of these hydrates however hydrolysis might appear along with dehydration. The HCl produced during the hydrolysis degrades and corrodes the storage system. Our GGA-DFT results show that the enthalpy charge during proton formation (an important step in hydrolysis) is much higher for CaCl2·2H2O (33.75 kcal/mol) than for MgCl2·2H2O (19.55 kcal/mol). This is a strong indicator that hydrolysis can be minimized by appropriate chemical mixing of CaCl2 and Mg Cl2 hydrates, which is also confirmed by recent experimental studies. GGA-DFT calculations were performed to obtain and analyze the optimized structures, charge distributions, bonding indicators and harmonic frequencies of various chemical mixtures hydrates and compared them to their elementary salts hydrates. We have further assessed the equilibrium products concentration of dehydration/hydrolysis of the chemical mixtures under a wide range of operating conditions. We observed that chemical mixing leads to an increase of the onset hydrolysis temperature with a maximum value of 79 K, thus increasing the resistance against hydrolysis with respect to the elementary salt hydrates. We also found that the chemical mixing of CaCl2 and MgCl2 hydrates widens the operating dehydration temperature range by a maximum value of 182 K (CaMg2Cl6·2H2O) and lowers the binding enthalpy with respect to the physical mixture by ≈65 kcal/mol for TCM based heat storage systems. PMID:28983386

  2. 40 CFR 180.1103 - Isomate-C; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... requirements of a tolerance in or on all raw agricultural commodities when formulated in polyethylene pheromone...

  3. 40 CFR 180.1070 - Sodium chlorite; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... agricultural practice as a seed-soak treatment in the growing of the raw agricultural commodities vegetable...

  4. 40 CFR 180.1103 - Isomate-C; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... requirements of a tolerance in or on all raw agricultural commodities when formulated in polyethylene pheromone...

  5. 40 CFR 180.1070 - Sodium chlorite; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... agricultural practice as a seed-soak treatment in the growing of the raw agricultural commodities vegetable...

  6. Evaluation of the nephrotoxicity of complex mixtures containing organics and metals: advantages and disadvantages of the use of real-world complex mixtures.

    PubMed

    Simmons, J E; Yang, R S; Berman, E

    1995-02-01

    As part of a multidisciplinary health effects study, the nephrotoxicity of complex industrial waste mixtures was assessed. Adult, male Fischer 344 rats were gavaged with samples of complex industrial waste and nephrotoxicity evaluated 24 hr later. Of the 10 tested samples, 4 produced increased absolute or relative kidney weight, or both, coupled with a statistically significant alteration in at least one of the measured serum parameters (urea nitrogen (BUN), creatinine (CREAT), and BUN/CREAT ratio). Although the waste samples had been analyzed for a number of organic chemicals and 7 of the 10 samples were analyzed also for 12 elemental metals and metalloids, their nephrotoxicity was not readily predicted from the partial chemical characterization data. Because the chemical form or speciation of the metals was unknown, it was not possible to estimate their contribution to the observed biological response. Various experimental approaches, including use of real-world complex mixtures, chemically defined synthetic mixtures, and simple mixtures, will be necessary to adequately determine the potential human health risk from exposure to complex chemical mixtures.

  7. 75 FR 37301 - Exempt Chemical Mixtures Containing Gamma-Butyrolactone

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-29

    ... their central nervous system (CNS) depressant effect. An overdose from GBL or GHB may result in... the central nervous system that is substantially similar to or greater than the stimulant, depressant, or hallucinogenic effect on the central nervous system of a controlled substance in schedule I or II...

  8. Phase transition and chemical decomposition of hydrogen peroxide and its water mixtures under high pressures.

    PubMed

    Chen, Jing-Yin; Kim, Minseob; Yoo, Choong-Shik; Dattelbaum, Dana M; Sheffield, Stephen

    2010-06-07

    We have studied the pressure-induced phase transition and chemical decomposition of hydrogen peroxide and its mixtures with water to 50 GPa, using confocal micro-Raman and synchrotron x-ray diffractions. The x-ray results indicate that pure hydrogen peroxide crystallizes into a tetragonal structure (P4(1)2(1)2), the same structure previously found in 82.7% H(2)O(2) at high pressures and in pure H(2)O(2) at low temperatures. The tetragonal phase (H(2)O(2)-I) is stable to 15 GPa, above which transforms into an orthorhombic structure (H(2)O(2)-II) over a relatively large pressure range between 13 and 18 GPa. Inferring from the splitting of the nu(s)(O-O) stretching mode, the phase I-to-II transition pressure decreases in diluted H(2)O(2) to around 7 GPa for the 41.7% H(2)O(2) and 3 GPa for the 9.5%. Above 18 GPa H(2)O(2)-II gradually decomposes to a mixture of H(2)O and O(2), which completes at around 40 GPa for pure and 45 GPa for the 9.5% H(2)O(2). Upon pressure unloading, H(2)O(2) also decomposes to H(2)O and O(2) mixtures across the melts, occurring at 2.5 GPa for pure and 1.5 GPa for the 9.5% mixture. At H(2)O(2) concentrations below 20%, decomposed mixtures form oxygen hydrate clathrates at around 0.8 GPa--just after H(2)O melts. The compression data of pure H(2)O(2) and the stability data of the mixtures seem to indicate that the high-pressure decomposition is likely due to the pressure-induced densification, whereas the low-pressure decomposition is related to the heterogeneous nucleation process associated with H(2)O(2) melting.

  9. Computational estimation of errors generated by lumping of physiologically-based pharmacokinetic (PBPK) interaction models of inhaled complex chemical mixtures

    EPA Science Inventory

    Many cases of environmental contamination result in concurrent or sequential exposure to more than one chemical. However, limitations of available resources make it unlikely that experimental toxicology will provide health risk information about all the possible mixtures to which...

  10. A COMPARISON OF THE LETHAL AND SUBLETHAL TOXICITY OF ORGANIC CHEMICAL MIXTURES TO THE FATHEAD MINNOW (PIMEPHALES PROMELAS)

    EPA Science Inventory

    The joint toxic effects of known binary and multiple organic chemical mixtures to the fathead minnow (Pimephales promelas) were defined at both the 96-h 50% lethal effect concentration (LC50) and sublethal (32-d growth) response levels for toxicants with a narcosis I, narcosis II...

  11. MIXING RATIO INFLUENCES HALOACETIC ACID (HAA) MIXTURE TOXICITY

    EPA Science Inventory

    Mixtures of the same type (for example, disinfection byproduct mixtures) often contain the same chemicals, but at varying concentrations. The objective of the present study was to examine the influence of mixing ratio (the concentrations of chemicals relative to one another) on ...

  12. Mixtures Research at NIEHS: An Evolving Program

    PubMed Central

    Rider, Cynthia V; Carlin, Danielle J; DeVito, Micheal J; Thompson, Claudia L; Walker, Nigel J

    2014-01-01

    The National Institute of Environmental Health Sciences (NIEHS) has a rich history in evaluating the toxicity of mixtures. The types of mixtures assessed by the Division of the National Toxicology Program (DNTP) and the extramural community (through the Division of Extramural Research and Training (DERT)) have included a broad range of chemicals and toxicants, with each study having a unique set of questions and design considerations. Some examples of the types of mixtures studied include: groundwater contaminants, pesticides/fertilizers, dioxin-like chemicals (assessing the toxic equivalency approach), drug combinations, air pollution, metals, polycyclic aromatic hydrocarbons, technical mixtures (e.g. pentachlorophenol, flame retardants), and mixed entities (e.g. herbals, asbestos). These endeavors have provided excellent data on the toxicity of specific mixtures and have been informative to the human health risk assessment process in general (e.g. providing data on low dose exposures to environmental chemicals). However, the mixtures research effort at NIEHS, to date, has been driven by test article nominations to the DNTP or by investigator-initiated research through DERT. Recently, the NIEHS has embarked upon an effort to coordinate mixtures research across both intramural and extramural divisions in order to maximize mixtures research results. A path forward for NIEHS mixtures research will be based on feedback from a Request for Information (RFI) designed to gather up-to-date views on the knowledge gaps and roadblocks to evaluating mixtures and performing cumulative risk assessment, and a workshop organized to bring together mixtures experts from risk assessment, exposure science, biology, epidemiology, and statistics. The future of mixtures research at NIEHS will include projects from nominations to DNTP, studies by extramural investigators, and collaborations across government agencies that address high-priority questions in the field of mixtures research

  13. 46 CFR 28.60 - Exemption letter.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... VESSELS General Provisions § 28.60 Exemption letter. (a) Types of exemptions. (1) Specific exemption means... for an exemption of either type must be in writing, have specific reasons for the request, and be sent... vessel to which any exemption applies. (e) Right of appeal. Any person directly affected by a decision or...

  14. Effects of biologically-active chemical mixtures on fish in a wastewater-impacted urban stream

    USGS Publications Warehouse

    Barber, Larry B.; Brown, Gregory K.; Nettesheim, Todd G.; Murphy, Elizabeth W.; Bartell, Stephen E.; Schoenfuss, Heiko L.

    2011-01-01

    Stream flow in urban aquatic ecosystems often is maintained by water-reclamation plant (WRP) effluents that contain mixtures of natural and anthropogenic chemicals that persist through the treatment processes. In effluent-impactedstreams, aquatic organisms such as fish are continuously exposed to biologically-activechemicals throughout their life cycles. The North Shore Channel of the Chicago River (Chicago, Illinois) is part of an urban ecosystem in which > 80% of the annual flow consists of effluent from the North Side WRP. In this study, multiple samplings of the effluent and stream water were conducted and fish (largemouth bass and carp) were collected on 2 occasions from the North Shore Channel. Fish also were collected once from the Outer Chicago Harbor in Lake Michigan, a reference site not impacted by WRP discharges. Over 100 organic chemicals with differing behaviors and biological effects were measured, and 23 compounds were detected in all of the water samples analyzed. The most frequently detected and highest concentration (> 100 μg/L) compounds were ethylenediaminetetraacetic acid and 4-nonylphenolmono-to-tetraethoxycarboxylic acids. Other biologically-activechemicals including bisphenol A, 4-nonylphenol, 4-nonylphenolmono-to-tetraethoxylates, 4-tert-octylphenol, and 4-tert-octylphenolmono-to-tetraethoxylates were detected at lower concentrations (cis-androsterone were detected at even lower concentrations (< 0.005 μg/L). There were slight differences in concentrations between the North Side WRP effluent and the North Shore Channel, indicating minimal in-stream attenuation. Fish populations are continuously exposed to mixtures of biologically-activechemicals because of the relative persistency of the chemicals with respect to stream hydraulic residence time, and the lack of a fresh water source for dilution. The majority of male fish exhibited vitellogenin induction, a physiological response consistent with exposure to estrogenic compounds. Tissue

  15. 40 CFR 180.1167 - Allyl isothiocyanate as a component of food grade oil of mustard; exemption from the requirement...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Allyl isothiocyanate as a component of food grade oil of mustard; exemption from the requirement of a tolerance. 180.1167 Section 180.1167 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES I...

  16. 40 CFR 180.1022 - Iodine-detergent complex; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN... a tolerance. The aqueous solution of hydriodic acid and elemental iodine, including one or both of...

  17. 45 CFR 705.13 - Exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... exemptions: (1) Appeals, Grievances, and Complaints (staff)—Commission Project, CRC-001. Exempt partially...) Complaints, CRC-003—Exempt partially under 5 U.S.C. 552a(k)(2). The reasons for possibly asserting the... endangering these sources. (3) Commission projects, CRC-004—Partially exempt under 5 U.S.C. 552a(k)(2). The...

  18. 32 CFR 701.113 - PA exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... DOCUMENTS AFFECTING THE PUBLIC DON Privacy Program § 701.113 PA exemptions. (a) Exempt systems of records. 5... records that is filed in a non-exempt system of records retains its exempt status. (e) Types of exemptions.... They are: (i) “(k)(1)”: Information which is properly classified under E.O. in the interest of national...

  19. Demonstration of a rapidly-swept external cavity quantum cascade laser for rapid and sensitive quantification of chemical mixtures

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brumfield, Brian E.; Taubman, Matthew S.; Phillips, Mark C.

    2016-02-13

    A rapidly-swept external cavity quantum cascade laser (ECQCL) system for fast open-path quantification of multiple chemicals and mixtures is presented. The ECQCL system is swept over its entire tuning range (>100 cm-1) at frequencies up to 200 Hz. At 200 Hz the wavelength tuning rate and spectral resolution are 2x104 cm-1/sec and < 0.2 cm-1, respectively. The capability of the current system to quantify changes in chemical concentrations on millesecond timescales is demonstrated at atmospheric pressure using an open-path multi-pass cell. The detection limits for chemicals ranged from ppb to ppm levels depending on the absorption cross-section.

  20. New approach in direct-simulation of gas mixtures

    NASA Technical Reports Server (NTRS)

    Chung, Chan-Hong; De Witt, Kenneth J.; Jeng, Duen-Ren

    1991-01-01

    Results are reported for an investigation of a new direct-simulation Monte Carlo method by which energy transfer and chemical reactions are calculated. The new method, which reduces to the variable cross-section hard sphere model as a special case, allows different viscosity-temperature exponents for each species in a gas mixture when combined with a modified Larsen-Borgnakke phenomenological model. This removes the most serious limitation of the usefulness of the model for engineering simulations. The necessary kinetic theory for the application of the new method to mixtures of monatomic or polyatomic gases is presented, including gas mixtures involving chemical reactions. Calculations are made for the relaxation of a diatomic gas mixture, a plane shock wave in a gas mixture, and a chemically reacting gas flow along the stagnation streamline in front of a hypersonic vehicle. Calculated results show that the introduction of different molecular interactions for each species in a gas mixture produces significant differences in comparison with a common molecular interaction for all species in the mixture. This effect should not be neglected for accurate DSMC simulations in an engineering context.

  1. Structure-reactivity modeling using mixture-based representation of chemical reactions.

    PubMed

    Polishchuk, Pavel; Madzhidov, Timur; Gimadiev, Timur; Bodrov, Andrey; Nugmanov, Ramil; Varnek, Alexandre

    2017-09-01

    We describe a novel approach of reaction representation as a combination of two mixtures: a mixture of reactants and a mixture of products. In turn, each mixture can be encoded using an earlier reported approach involving simplex descriptors (SiRMS). The feature vector representing these two mixtures results from either concatenated product and reactant descriptors or the difference between descriptors of products and reactants. This reaction representation doesn't need an explicit labeling of a reaction center. The rigorous "product-out" cross-validation (CV) strategy has been suggested. Unlike the naïve "reaction-out" CV approach based on a random selection of items, the proposed one provides with more realistic estimation of prediction accuracy for reactions resulting in novel products. The new methodology has been applied to model rate constants of E2 reactions. It has been demonstrated that the use of the fragment control domain applicability approach significantly increases prediction accuracy of the models. The models obtained with new "mixture" approach performed better than those required either explicit (Condensed Graph of Reaction) or implicit (reaction fingerprints) reaction center labeling.

  2. TSCA Chemical Data Reporting Fact Sheet: Imported Articles

    EPA Pesticide Factsheets

    This fact sheet provides guidance and sample reporting scenarios on the reporting exemption for the import of a chemical substance as part of an article, for purposes of the Chemical Data Reporting (CDR) rule.

  3. 29 CFR 784.137 - Relationship of exemption to exemption for “offshore” activities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... reasons advanced for exemption of employment in “shore” operations, now listed in section 13(b)(4), at the... Exemptions Provisions Relating to Fishing and Aquatic Products General Character and Scope of the Section 13... section 13(a)(5) to section 13(b)(4). The exemption of employment in these “shore” operations may be...

  4. Chemical structure influence on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux

    NASA Astrophysics Data System (ADS)

    Padgett, Mark C.; Tick, Geoffrey R.; Carroll, Kenneth C.; Burke, William R.

    2017-03-01

    The influence of chemical structure on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux was examined. The variability of measured and UNIFAC modeled NAPL activity coefficients as a function of mole fraction was compared for two NAPL mixtures containing structurally-different contaminants of concern including toluene (TOL) or trichloroethene (TCE) within a hexadecane (HEXDEC) matrix. The results showed that dissolution from the NAPL mixtures transitioned from ideality for mole fractions > 0.05 to nonideality as mole fractions decreased. In particular, the TCE generally exhibited more ideal dissolution behavior except at lower mole fractions, and may indicate greater structural/polarity similarity between the two compounds. Raoult's Law and UNIFAC generally under-predicted the batch experiment results for TOL:HEXDEC mixtures especially for mole fractions ≤ 0.05. The dissolution rate coefficients were similar for both TOL and TCE over all mole fractions tested. Mass flux reduction (MFR) analysis showed that more efficient removal behavior occurred for TOL and TCE with larger mole fractions compared to the lower initial mole fraction mixtures (i.e. < 0.2). However, compared to TOL, TCE generally exhibited more efficient removal behavior over all mole fractions tested and may have been the result of structural and molecular property differences between the compounds. Activity coefficient variability as a function of mole fraction was quantified through regression analysis and incorporated into dissolution modeling analyses for the dynamic flushing experiments. TOL elution concentrations were modeled (predicted) reasonable well using ideal and equilibrium assumptions, but the TCE elution concentrations could not be predicted using the ideal model. Rather, the dissolution modeling demonstrated that TCE elution was better described by the nonideal model whereby NAPL-phase activity coefficient varied as a function of COC mole

  5. Pesticide Emergency Exemptions

    EPA Pesticide Factsheets

    A state or federal agency can request an emergency exemptions when a serious pest problem jeopardizes production of agricultural goods or public health but no pesticides are currently registered for that situation. Learn how to request emergency exemption.

  6. 32 CFR 1701.20 - Exemption policies.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... INTELLIGENCE ADMINISTRATION OF RECORDS UNDER THE PRIVACY ACT OF 1974 Exemption of Record Systems Under the Privacy Act § 1701.20 Exemption policies. (a) General. The DNI has determined that invoking exemptions under the Privacy Act and continuing exemptions previously asserted by agencies whose records ODNI...

  7. 29 CFR 779.347 - Exemption limited to “recognized retail establishment”; factories not exempt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Exemption limited to ârecognized retail establishmentâ... Retail or Service Establishments Engaging in Manufacturing and Processing Activities; Section 13(a)(4) § 779.347 Exemption limited to “recognized retail establishment”; factories not exempt. The section 13(a...

  8. 29 CFR 779.347 - Exemption limited to “recognized retail establishment”; factories not exempt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Exemption limited to ârecognized retail establishmentâ... Retail or Service Establishments Engaging in Manufacturing and Processing Activities; Section 13(a)(4) § 779.347 Exemption limited to “recognized retail establishment”; factories not exempt. The section 13(a...

  9. 29 CFR 779.347 - Exemption limited to “recognized retail establishment”; factories not exempt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Exemption limited to ârecognized retail establishmentâ... Retail or Service Establishments Engaging in Manufacturing and Processing Activities; Section 13(a)(4) § 779.347 Exemption limited to “recognized retail establishment”; factories not exempt. The section 13(a...

  10. 29 CFR 779.347 - Exemption limited to “recognized retail establishment”; factories not exempt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Exemption limited to ârecognized retail establishmentâ... Retail or Service Establishments Engaging in Manufacturing and Processing Activities; Section 13(a)(4) § 779.347 Exemption limited to “recognized retail establishment”; factories not exempt. The section 13(a...

  11. 40 CFR 180.1269 - Bacillus mycoides Isolate J: exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN... when used as a fungicide on pecans, potatoes, sugar beets, tomatoes, and peppers in accordance with the...

  12. 10 CFR 150.10 - Persons exempt.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Persons exempt. 150.10 Section 150.10 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXEMPTIONS AND CONTINUED REGULATORY AUTHORITY IN AGREEMENT STATES AND IN OFFSHORE WATERS UNDER SECTION 274 Exemptions in Agreement States § 150.10 Persons exempt. Except as...

  13. 10 CFR 150.10 - Persons exempt.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 2 2014-01-01 2014-01-01 false Persons exempt. 150.10 Section 150.10 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXEMPTIONS AND CONTINUED REGULATORY AUTHORITY IN AGREEMENT STATES AND IN OFFSHORE WATERS UNDER SECTION 274 Exemptions in Agreement States § 150.10 Persons exempt. Except as...

  14. 10 CFR 150.10 - Persons exempt.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 2 2011-01-01 2011-01-01 false Persons exempt. 150.10 Section 150.10 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXEMPTIONS AND CONTINUED REGULATORY AUTHORITY IN AGREEMENT STATES AND IN OFFSHORE WATERS UNDER SECTION 274 Exemptions in Agreement States § 150.10 Persons exempt. Except as...

  15. 10 CFR 150.10 - Persons exempt.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 2 2013-01-01 2013-01-01 false Persons exempt. 150.10 Section 150.10 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXEMPTIONS AND CONTINUED REGULATORY AUTHORITY IN AGREEMENT STATES AND IN OFFSHORE WATERS UNDER SECTION 274 Exemptions in Agreement States § 150.10 Persons exempt. Except as...

  16. 10 CFR 55.11 - Specific exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 2 2014-01-01 2014-01-01 false Specific exemptions. 55.11 Section 55.11 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) OPERATORS' LICENSES Exemptions § 55.11 Specific exemptions. The Commission may, upon application by an interested person, or upon its own initiative, grant such exemptions from...

  17. 10 CFR 55.11 - Specific exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Specific exemptions. 55.11 Section 55.11 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) OPERATORS' LICENSES Exemptions § 55.11 Specific exemptions. The Commission may, upon application by an interested person, or upon its own initiative, grant such exemptions from...

  18. 40 CFR 157.24 - Exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Exemptions. 157.24 Section 157.24 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS PACKAGING REQUIREMENTS FOR PESTICIDES AND DEVICES Child-Resistant Packaging § 157.24 Exemptions. (a) General exemptions...

  19. Acute toxicity to goldfish of mixtures of chloramines, copper, and linear alkylate sulfonate

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tsai, C.F.; McKee, J.A.

    1980-01-01

    The toxicity to goldfish (Carassius auratus) of mixtures of chloramines, copper, and linear alkylate sulfonate (LAS) was studied by continuous-flow toxicity tests during an exposure period of 96 hours. The individual toxicities of these three chemicals are either additive or synergistic in mixtures, depending on the rate of toxic action of the individual chemical, the toxicity ratio of the chemicals in the mixtures, and the concentration of the mixtures.

  20. 10 CFR 40.14 - Specific exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Specific exemptions. 40.14 Section 40.14 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF SOURCE MATERIAL Exemptions § 40.14 Specific exemptions. (a) The... interest. (b) [Reserved] (c) The Department of Energy is exempt from the requirements of this part to the...

  1. 50 CFR 660.406 - Exempted fishing.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Exempted fishing. 660.406 Section 660.406... Exempted fishing. (a) NMFS may allow such exempted fishing in the fishery management area as may be... accustomed fishing grounds in the fishery management area. (b) NMFS will not allow any exempted fishery...

  2. 50 CFR 697.22 - Exempted fishing.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Exempted fishing. 697.22 Section 697.22... § 697.22 Exempted fishing. The Regional Administrator or Director may exempt any person or vessel from the requirements of this part for the conduct of exempted fishing beneficial to the management of the...

  3. 50 CFR 697.22 - Exempted fishing.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Exempted fishing. 697.22 Section 697.22... § 697.22 Exempted fishing. The Regional Administrator or Director may exempt any person or vessel from the requirements of this part for the conduct of exempted fishing beneficial to the management of the...

  4. 50 CFR 660.406 - Exempted fishing.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Exempted fishing. 660.406 Section 660.406... Exempted fishing. (a) NMFS may allow such exempted fishing in the fishery management area as may be... accustomed fishing grounds in the fishery management area. (b) NMFS will not allow any exempted fishery...

  5. 50 CFR 697.22 - Exempted fishing.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Exempted fishing. 697.22 Section 697.22... § 697.22 Exempted fishing. The Regional Administrator or Director may exempt any person or vessel from the requirements of this part for the conduct of exempted fishing beneficial to the management of the...

  6. 7 CFR 929.158 - Exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... organically-grown cranberries are exempted from the volume regulation as recommended by the Committee and approved by the Secretary, the following provisions to these exemptions shall apply: (a) Sales of packed-out cranberries intended for sales to consumers in fresh form shall be exempt from volume regulation...

  7. 32 CFR 320.12 - Exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... NATIONAL GEOSPATIAL-INTELLIGENCE AGENCY (NGA) PRIVACY § 320.12 Exemptions. (a) Exempt systems of record. All systems of records maintained by the NGA and its components shall be exempt from the requirements... the investigation or prosecutable interest by the NGA or other agencies. This could seriously...

  8. 32 CFR 320.12 - Exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 2 2012-07-01 2012-07-01 false Exemptions. 320.12 Section 320.12 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) PRIVACY PROGRAM NATIONAL GEOSPATIAL-INTELLIGENCE AGENCY (NGA) PRIVACY § 320.12 Exemptions. (a) Exempt systems of record...

  9. 32 CFR 320.12 - Exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Exemptions. 320.12 Section 320.12 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) PRIVACY PROGRAM NATIONAL GEOSPATIAL-INTELLIGENCE AGENCY (NGA) PRIVACY § 320.12 Exemptions. (a) Exempt systems of record...

  10. Chemical thermodynamics of ultrasound speed in solutions and liquid mixtures.

    PubMed

    Reis, João Carlos R; Santos, Angela F S; Lampreia, Isabel M S

    2010-02-01

    A comprehensive formalism is developed to treat thermodynamically speed of ultrasound data for solutions and liquid mixtures. For solutions, the apparent speed of ultrasound of a solute is introduced and proposed to take the place of empirically defined quantities. The partial speed of ultrasound of a solute is defined and related to the partial molar volume and partial molar isentropic compression. For liquid mixtures, the concept of speed of sound before mixing pure liquids is presented and used to define the change in speed of ultrasound upon ideal mixing, which is predicted to be generally a negative quantity. A new thermodynamic equation is derived linking the values for excess speed of ultrasound, excess molar volume and excess molar isentropic compression of a mixture, and its applications are discussed. Ideal and excess apparent speeds of ultrasound, as well as ideal and excess partial speeds of ultrasound, are defined for substances making up a liquid mixture. Accurate speeds of ultrasound in 31 mixtures of water with the amphiphile 2-(ethylamino)ethanol at 293.15 K are reported. These data are used to demonstrate the ability of the apparent speed of ultrasound to describe the impact of solutes on sonic properties of solutions and the advantages of analysing thermodynamic properties of binary liquid mixtures in terms of the dependence on composition of Balankina's ratios between excess and ideal values. It is concluded that the new thermodynamic functions defined for speeds of ultrasound in solutions and liquid mixtures give, at the least, equivalent information on molecular aspects to the usual functions related to the isentropic compressibility, without needing density data for this purpose.

  11. General multi-group macroscopic modeling for thermo-chemical non-equilibrium gas mixtures.

    PubMed

    Liu, Yen; Panesi, Marco; Sahai, Amal; Vinokur, Marcel

    2015-04-07

    This paper opens a new door to macroscopic modeling for thermal and chemical non-equilibrium. In a game-changing approach, we discard conventional theories and practices stemming from the separation of internal energy modes and the Landau-Teller relaxation equation. Instead, we solve the fundamental microscopic equations in their moment forms but seek only optimum representations for the microscopic state distribution function that provides converged and time accurate solutions for certain macroscopic quantities at all times. The modeling makes no ad hoc assumptions or simplifications at the microscopic level and includes all possible collisional and radiative processes; it therefore retains all non-equilibrium fluid physics. We formulate the thermal and chemical non-equilibrium macroscopic equations and rate coefficients in a coupled and unified fashion for gases undergoing completely general transitions. All collisional partners can have internal structures and can change their internal energy states after transitions. The model is based on the reconstruction of the state distribution function. The internal energy space is subdivided into multiple groups in order to better describe non-equilibrium state distributions. The logarithm of the distribution function in each group is expressed as a power series in internal energy based on the maximum entropy principle. The method of weighted residuals is applied to the microscopic equations to obtain macroscopic moment equations and rate coefficients succinctly to any order. The model's accuracy depends only on the assumed expression of the state distribution function and the number of groups used and can be self-checked for accuracy and convergence. We show that the macroscopic internal energy transfer, similar to mass and momentum transfers, occurs through nonlinear collisional processes and is not a simple relaxation process described by, e.g., the Landau-Teller equation. Unlike the classical vibrational energy

  12. 45 CFR 1705.12 - Exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 4 2012-10-01 2012-10-01 false Exemptions. 1705.12 Section 1705.12 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL COMMISSION ON LIBRARIES AND INFORMATION SCIENCE PRIVACY REGULATIONS § 1705.12 Exemptions. No Commission records system is exempted from the provisions of...

  13. 45 CFR 1705.12 - Exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 4 2013-10-01 2013-10-01 false Exemptions. 1705.12 Section 1705.12 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL COMMISSION ON LIBRARIES AND INFORMATION SCIENCE PRIVACY REGULATIONS § 1705.12 Exemptions. No Commission records system is exempted from the provisions of...

  14. 45 CFR 1705.12 - Exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 4 2014-10-01 2014-10-01 false Exemptions. 1705.12 Section 1705.12 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL COMMISSION ON LIBRARIES AND INFORMATION SCIENCE PRIVACY REGULATIONS § 1705.12 Exemptions. No Commission records system is exempted from the provisions of...

  15. 45 CFR 1705.12 - Exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 4 2011-10-01 2011-10-01 false Exemptions. 1705.12 Section 1705.12 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL COMMISSION ON LIBRARIES AND INFORMATION SCIENCE PRIVACY REGULATIONS § 1705.12 Exemptions. No Commission records system is exempted from the provisions of...

  16. 22 CFR 1003.8 - Exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 2 2013-04-01 2009-04-01 true Exemptions. 1003.8 Section 1003.8 Foreign Relations INTER-AMERICAN FOUNDATION RULES SAFEGUARDING PERSONAL INFORMATION IN IAF RECORDS § 1003.8 Exemptions. No Inter-American Foundation records system or systems as such are exempted from the provisions...

  17. 18 CFR 701.314 - Exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Exemptions. 701.314 Section 701.314 Conservation of Power and Water Resources WATER RESOURCES COUNCIL COUNCIL ORGANIZATION Protection of Privacy § 701.314 Exemptions. No Council records system or systems are exempted from the...

  18. 18 CFR 701.314 - Exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Exemptions. 701.314 Section 701.314 Conservation of Power and Water Resources WATER RESOURCES COUNCIL COUNCIL ORGANIZATION Protection of Privacy § 701.314 Exemptions. No Council records system or systems are exempted from the...

  19. 18 CFR 701.314 - Exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Exemptions. 701.314 Section 701.314 Conservation of Power and Water Resources WATER RESOURCES COUNCIL COUNCIL ORGANIZATION Protection of Privacy § 701.314 Exemptions. No Council records system or systems are exempted from the...

  20. 18 CFR 701.314 - Exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Exemptions. 701.314 Section 701.314 Conservation of Power and Water Resources WATER RESOURCES COUNCIL COUNCIL ORGANIZATION Protection of Privacy § 701.314 Exemptions. No Council records system or systems are exempted from the...

  1. 18 CFR 701.314 - Exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Exemptions. 701.314 Section 701.314 Conservation of Power and Water Resources WATER RESOURCES COUNCIL COUNCIL ORGANIZATION Protection of Privacy § 701.314 Exemptions. No Council records system or systems are exempted from the...

  2. 45 CFR 1705.12 - Exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Exemptions. 1705.12 Section 1705.12 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL COMMISSION ON LIBRARIES AND INFORMATION SCIENCE PRIVACY REGULATIONS § 1705.12 Exemptions. No Commission records system is exempted from the provisions of...

  3. Exploring the plasma chemistry in microwave chemical vapor deposition of diamond from C/H/O gas mixtures.

    PubMed

    Kelly, Mark W; Richley, James C; Western, Colin M; Ashfold, Michael N R; Mankelevich, Yuri A

    2012-09-27

    Microwave (MW)-activated CH(4)/CO(2)/H(2) gas mixtures operating under conditions relevant to diamond chemical vapor deposition (i.e., X(C/Σ) = X(elem)(C)/(X(elem)(C) + X(elem)(O)) ≈ 0.5, H(2) mole fraction = 0.3, pressure, p = 150 Torr, and input power, P = 1 kW) have been explored in detail by a combination of spatially resolved absorption measurements (of CH, C(2)(a), and OH radicals and H(n = 2) atoms) within the hot plasma region and companion 2-dimensional modeling of the plasma. CO and H(2) are identified as the dominant species in the plasma core. The lower thermal conductivity of such a mixture (cf. the H(2)-rich plasmas used in most diamond chemical vapor deposition) accounts for the finding that CH(4)/CO(2)/H(2) plasmas can yield similar maximal gas temperatures and diamond growth rates at lower input powers than traditional CH(4)/H(2) plasmas. The plasma chemistry and composition is seen to switch upon changing from oxygen-rich (X(C/Σ) < 0.5) to carbon-rich (X(C/Σ) > 0.5) source gas mixtures and, by comparing CH(4)/CO(2)/H(2) (X(C/Σ) = 0.5) and CO/H(2) plasmas, to be sensitive to the choice of source gas (by virtue of the different prevailing gas activation mechanisms), in contrast to C/H process gas mixtures. CH(3) radicals are identified as the most abundant C(1)H(x) [x = 0-3] species near the growing diamond surface within the process window for successful diamond growth (X(C/Σ) ≈ 0.5-0.54) identified by Bachmann et al. (Diamond Relat. Mater.1991, 1, 1). This, and the findings of similar maximal gas temperatures (T(gas) ~2800-3000 K) and H atom mole fractions (X(H)~5-10%) to those found in MW-activated C/H plasmas, points to the prevalence of similar CH(3) radical based diamond growth mechanisms in both C/H and C/H/O plasmas.

  4. 48 CFR 52.223-14 - Toxic Chemical Release Reporting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Toxic Chemical Release....223-14 Toxic Chemical Release Reporting. As prescribed in 23.906(b), insert the following clause: Toxic Chemical Release Reporting (AUG 2003) (a) Unless otherwise exempt, the Contractor, as owner or...

  5. Extension of a hybrid particle-continuum method for a mixture of chemical species

    NASA Astrophysics Data System (ADS)

    Verhoff, Ashley M.; Boyd, Iain D.

    2012-11-01

    Due to the physical accuracy and numerical efficiency achieved by analyzing transitional, hypersonic flow fields with hybrid particle-continuum methods, this paper describes a Modular Particle-Continuum (MPC) method and its extension to include multiple chemical species. Considerations that are specific to a hybrid approach for simulating gas mixtures are addressed, including a discussion of the Chapman-Enskog velocity distribution function (VDF) for near-equilibrium flows, and consistent viscosity models for the individual CFD and DSMC modules of the MPC method. Representative results for a hypersonic blunt-body flow are then presented, where the flow field properties, surface properties, and computational performance are compared for simulations employing full CFD, full DSMC, and the MPC method.

  6. 40 CFR 87.7 - Exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Exemptions. 87.7 Section 87.7... POLLUTION FROM AIRCRAFT AND AIRCRAFT ENGINES General Provisions § 87.7 Exemptions. (a) Exemptions based on..., with the concurrence of the Administrator, that application of any standard under § 87.21 is not...

  7. 14 CFR 1206.300 - Exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Exemptions. 1206.300 Section 1206.300 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION AVAILABILITY OF AGENCY RECORDS TO MEMBERS OF THE PUBLIC Exemptions § 1206.300 Exemptions. (a) Under 5 U.S.C. 552(b) Agency records falling...

  8. 40 CFR 180.1246 - Yeast Extract Hydrolysate from Saccharomyces cerevisiae: exemption from the requirement of a...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Hydrolysate from Saccharomyces cerevisiae on all food commodities when applied/used for the management of... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1246 Yeast Extract Hydrolysate from...

  9. 40 CFR 180.1101 - Parasitic (parasitoid) and predatory insects; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... with good agricultural and pest control practices to control insect pests of stored raw whole grains... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1101 Parasitic (parasitoid) and...

  10. 40 CFR 180.1101 - Parasitic (parasitoid) and predatory insects; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... with good agricultural and pest control practices to control insect pests of stored raw whole grains... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1101 Parasitic (parasitoid) and...

  11. 40 CFR 180.1101 - Parasitic (parasitoid) and predatory insects; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... with good agricultural and pest control practices to control insect pests of stored raw whole grains... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1101 Parasitic (parasitoid) and...

  12. 40 CFR 180.1101 - Parasitic (parasitoid) and predatory insects; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... with good agricultural and pest control practices to control insect pests of stored raw whole grains... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1101 Parasitic (parasitoid) and...

  13. 40 CFR 180.1101 - Parasitic (parasitoid) and predatory insects; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... with good agricultural and pest control practices to control insect pests of stored raw whole grains... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1101 Parasitic (parasitoid) and...

  14. 40 CFR 180.1091 - Aluminum isopropoxide and aluminum secondary butoxide; exemption from the requirement of a...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1091 Aluminum isopropoxide and aluminum... tolerance when used in accordance with good agricultural practices as stabilizers in formulations of the...

  15. 40 CFR 180.1091 - Aluminum isopropoxide and aluminum secondary butoxide; exemption from the requirement of a...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1091 Aluminum isopropoxide and aluminum... tolerance when used in accordance with good agricultural practices as stabilizers in formulations of the...

  16. 14 CFR 294.10 - Exemption authority.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... REGULATIONS CANADIAN CHARTER AIR TAXI OPERATORS Exemption § 294.10 Exemption authority. Canadian charter air taxi operators registered under this part are exempt from the following provisions of the Statute to...

  17. 14 CFR 294.10 - Exemption authority.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... REGULATIONS CANADIAN CHARTER AIR TAXI OPERATORS Exemption § 294.10 Exemption authority. Canadian charter air taxi operators registered under this part are exempt from the following provisions of the Statute to...

  18. 40 CFR 180.1196 - Peroxyacetic acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... antimicrobial treatment in solutions containing a diluted end use concentration of peroxyacetic acid up to 100... food commodities when used in sanitizing solutions containing a diluted end-use concentration of...

  19. 22 CFR 1101.9 - Exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Exemptions. 1101.9 Section 1101.9 Foreign Relations INTERNATIONAL BOUNDARY AND WATER COMMISSION, UNITED STATES AND MEXICO, UNITED STATES SECTION PRIVACY ACT OF 1974 § 1101.9 Exemptions. The following are exempt from disclosure under 5 U.S.C. 552a (j...

  20. 10 CFR 1004.10 - Exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Exemptions. 1004.10 Section 1004.10 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) FREEDOM OF INFORMATION § 1004.10 Exemptions. (a) 5 U.S.C. 552 exempts from all of its publication and disclosure requirements nine categories of records which are described in...

  1. 10 CFR 1004.10 - Exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Exemptions. 1004.10 Section 1004.10 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) FREEDOM OF INFORMATION § 1004.10 Exemptions. (a) 5 U.S.C. 552 exempts from all of its publication and disclosure requirements nine categories of records which are described in...

  2. 22 CFR 1101.9 - Exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 2 2012-04-01 2009-04-01 true Exemptions. 1101.9 Section 1101.9 Foreign Relations INTERNATIONAL BOUNDARY AND WATER COMMISSION, UNITED STATES AND MEXICO, UNITED STATES SECTION PRIVACY ACT OF 1974 § 1101.9 Exemptions. The following are exempt from disclosure under 5 U.S.C. 552a (j...

  3. 22 CFR 1101.9 - Exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 2 2011-04-01 2009-04-01 true Exemptions. 1101.9 Section 1101.9 Foreign Relations INTERNATIONAL BOUNDARY AND WATER COMMISSION, UNITED STATES AND MEXICO, UNITED STATES SECTION PRIVACY ACT OF 1974 § 1101.9 Exemptions. The following are exempt from disclosure under 5 U.S.C. 552a (j...

  4. 22 CFR 66.6 - Exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Exemptions. 66.6 Section 66.6 Foreign Relations DEPARTMENT OF STATE PUBLIC DIPLOMACY AND EXCHANGES AVAILABILITY OF THE RECORDS OF THE NATIONAL ENDOWMENT FOR DEMOCRACY § 66.6 Exemptions. NED reserves the right to withhold records and information that are exempt from...

  5. 75 FR 39707 - Prohibited Transaction Exemptions and Grant of Individual Exemptions Involving D-11448, The PNC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-12

    ... DEPARTMENT OF LABOR Employee Benefits Security Administration Prohibited Transaction Exemptions and Grant of Individual Exemptions Involving D-11448, The PNC Financial Services Group, Inc., 2010-19... Financial Services Group, Inc. Located in Pittsburgh, Pennsylvania [Prohibited Transaction Exemption 2010-19...

  6. 75 FR 8117 - Prohibited Transaction Exemptions and Grant of Individual Exemptions involving: 2010-01; Deutsche...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-23

    ...This document contains exemptions issued by the Department of Labor (the Department) from certain of the prohibited transaction restrictions of the Employee Retirement Income Security Act of 1974 (ERISA or the Act) and/or the Internal Revenue Code of 1986 (the Code). A notice was published in the Federal Register of the pendency before the Department of a proposal to grant such exemption. The notice set forth a summary of facts and representations contained in the application for exemption and referred interested persons to the application for a complete statement of the facts and representations. The application has been available for public inspection at the Department in Washington, DC. The notice also invited interested persons to submit comments on the requested exemption to the Department. In addition the notice stated that any interested person might submit a written request that a public hearing be held (where appropriate). The applicant has represented that it has complied with the requirements of the notification to interested persons. No requests for a hearing were received by the Department. Public comments were received by the Department as described in the granted exemption. The notice of proposed exemption was issued and the exemption is being granted solely by the Department because, effective December 31, 1978, section 102 of Reorganization Plan No. 4 of 1978, 5 U.S.C. App. 1 (1996), transferred the authority of the Secretary of the Treasury to issue exemptions of the type proposed to the Secretary of Labor.

  7. 45 CFR 613.5 - Exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 3 2013-10-01 2013-10-01 false Exemptions. 613.5 Section 613.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION PRIVACY ACT REGULATIONS § 613.5 Exemptions. (a) Fellowships and other support. Pursuant to 5 U.S.C. 552a(k)(6), the Foundation hereby exempts...

  8. 45 CFR 613.5 - Exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 3 2012-10-01 2012-10-01 false Exemptions. 613.5 Section 613.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION PRIVACY ACT REGULATIONS § 613.5 Exemptions. (a) Fellowships and other support. Pursuant to 5 U.S.C. 552a(k)(6), the Foundation hereby exempts...

  9. 45 CFR 613.5 - Exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 3 2014-10-01 2014-10-01 false Exemptions. 613.5 Section 613.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION PRIVACY ACT REGULATIONS § 613.5 Exemptions. (a) Fellowships and other support. Pursuant to 5 U.S.C. 552a(k)(6), the Foundation hereby exempts...

  10. 45 CFR 613.5 - Exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 3 2011-10-01 2011-10-01 false Exemptions. 613.5 Section 613.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION PRIVACY ACT REGULATIONS § 613.5 Exemptions. (a) Fellowships and other support. Pursuant to 5 U.S.C. 552a(k)(6), the Foundation hereby exempts...

  11. Chemical structure influence on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux.

    PubMed

    Padgett, Mark C; Tick, Geoffrey R; Carroll, Kenneth C; Burke, William R

    2017-03-01

    The influence of chemical structure on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux was examined. The variability of measured and UNIFAC modeled NAPL activity coefficients as a function of mole fraction was compared for two NAPL mixtures containing structurally-different contaminants of concern including toluene (TOL) or trichloroethene (TCE) within a hexadecane (HEXDEC) matrix. The results showed that dissolution from the NAPL mixtures transitioned from ideality for mole fractions >0.05 to nonideality as mole fractions decreased. In particular, the TCE generally exhibited more ideal dissolution behavior except at lower mole fractions, and may indicate greater structural/polarity similarity between the two compounds. Raoult's Law and UNIFAC generally under-predicted the batch experiment results for TOL:HEXDEC mixtures especially for mole fractions ≤0.05. The dissolution rate coefficients were similar for both TOL and TCE over all mole fractions tested. Mass flux reduction (MFR) analysis showed that more efficient removal behavior occurred for TOL and TCE with larger mole fractions compared to the lower initial mole fraction mixtures (i.e. <0.2). However, compared to TOL, TCE generally exhibited more efficient removal behavior over all mole fractions tested and may have been the result of structural and molecular property differences between the compounds. Activity coefficient variability as a function of mole fraction was quantified through regression analysis and incorporated into dissolution modeling analyses for the dynamic flushing experiments. TOL elution concentrations were modeled (predicted) reasonable well using ideal and equilibrium assumptions, but the TCE elution concentrations could not be predicted using the ideal model. Rather, the dissolution modeling demonstrated that TCE elution was better described by the nonideal model whereby NAPL-phase activity coefficient varied as a function of COC mole fraction

  12. EVALUATING QUANTITATIVE FORMULAS FOR DOSE-RESPONSE ASSESSMENT OF CHEMICAL MIXTURES

    EPA Science Inventory

    Risk assessment formulas are often distinguished from dose-response models by being rough but necessary. The evaluation of these rough formulas is described here, using the example of mixture risk assessment. Two conditions make the dose-response part of mixture risk assessment d...

  13. Endocrine-Disrupting Chemicals and Oil and Natural Gas Operations: Potential Environmental Contamination and Recommendations to Assess Complex Environmental Mixtures

    PubMed Central

    Kassotis, Christopher D.; Tillitt, Donald E.; Lin, Chung-Ho; McElroy, Jane A.; Nagel, Susan C.

    2015-01-01

    Background Hydraulic fracturing technologies, developed over the last 65 years, have only recently been combined with horizontal drilling to unlock oil and gas reserves previously deemed inaccessible. Although these technologies have dramatically increased domestic oil and natural gas production, they have also raised concerns for the potential contamination of local water supplies with the approximately 1,000 chemicals that are used throughout the process, including many known or suspected endocrine-disrupting chemicals. Objectives We discuss the need for an endocrine component to health assessments for drilling-dense regions in the context of hormonal and antihormonal activities for chemicals used. Methods We discuss the literature on a) surface and groundwater contamination by oil and gas extraction operations, and b) potential human exposure, particularly in the context of the total hormonal and antihormonal activities present in surface and groundwater from natural and anthropogenic sources; we also discuss initial analytical results and critical knowledge gaps. Discussion In light of the potential for environmental release of oil and gas chemicals that can disrupt hormone receptor systems, we recommend methods for assessing complex hormonally active environmental mixtures. Conclusions We describe a need for an endocrine-centric component for overall health assessments and provide information supporting the idea that using such a component will help explain reported adverse health trends as well as help develop recommendations for environmental impact assessments and monitoring programs. Citation Kassotis CD, Tillitt DE, Lin CH, McElroy JA, Nagel SC. 2016. Endocrine-disrupting chemicals and oil and natural gas operations: potential environmental contamination and recommendations to assess complex environmental mixtures. Environ Health Perspect 124:256–264; http://dx.doi.org/10.1289/ehp.1409535 PMID:26311476

  14. Concepts of risk assesment of complex chemical mixtures in laser pyrolysis fumes

    NASA Astrophysics Data System (ADS)

    Weber, Lothar W.; Meier, Thomas H.

    1996-01-01

    Laser-tissue interaction may generate by energy absorption a complex mixture of gaseous, volatile, semi-volatile and particular substances. At the time about 150 different components are known from IR-laser interaction with different organ tissues like liver, fat, muscle and skin. The laser-tissue interaction process thereby is dominated by heating processes, which is confirmed by the similarity of formed chemical products in comparison with conventional cooking processes for food preparation. With the identified chemical substances and relative amounts in backmind a walk along the think path of risk assessment with special reference to pyrolysis products is given. The main way of intake of pyrolysis products is the inhalative one, which results from the fine aerosols formed and the high spreading energy out of the irradiated source. The liberated amounts of irritative chemicals as (unsaturated) aldehydes, heterocycles of bad odor and possibly cancerogenic acting substances relates to some (mu) g/g of laser vaporized tissue. With regard to this exposure level in a hypothetic one cubic meter volume the occupational limit settings are far away. Even indoor air exposure levels are in nearly all cases underwent, for the content of bad smelling substances forces an effective ventilation. Up to now no laser typical chemical substance could be identified, which was not elsewhere known by frying or baking processes of meat, food or familiar. Starting with the GRAS concept of 1957 the process of risk assessment by modified food products and new ingredients is still improofing. The same process of risk assessment is governing the laser pyrolysis products of mammalian tissues. By use of sufficient suction around the laser tissue source the odor problems as well as the toxicological problems could be solved.

  15. 40 CFR 87.7 - Exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... § 87.7 Exemptions. Link to an amendment published at 77 FR 36381, June 18, 2012. (a) Exemptions based..., 1984; 70 FR 69686, Nov. 17, 2005] Effective Date Note: At 77 FR 36381, June 18, 2012, § 87.7 was... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Exemptions. 87.7 Section 87.7...

  16. Probabilistic human health risk assessment of degradation-related chemical mixtures in heterogeneous aquifers: Risk statistics, hot spots, and preferential channels

    NASA Astrophysics Data System (ADS)

    Henri, Christopher V.; Fernàndez-Garcia, Daniel; de Barros, Felipe P. J.

    2015-06-01

    The increasing presence of toxic chemicals released in the subsurface has led to a rapid growth of social concerns and the need to develop and employ models that can predict the impact of groundwater contamination on human health risk under uncertainty. Monitored natural attenuation is a common remediation action in many contamination cases. However, natural attenuation can lead to the production of daughter species of distinct toxicity that may pose challenges in pollution management strategies. The actual threat that these contaminants pose to human health depends on the interplay between the complex structure of the geological media and the toxicity of each pollutant byproduct. This work addresses human health risk for chemical mixtures resulting from the sequential degradation of a contaminant (such as a chlorinated solvent) under uncertainty through high-resolution three-dimensional numerical simulations. We systematically investigate the interaction between aquifer heterogeneity, flow connectivity, contaminant injection model, and chemical toxicity in the probabilistic characterization of health risk. We illustrate how chemical-specific travel times control the regime of the expected risk and its corresponding uncertainties. Results indicate conditions where preferential flow paths can favor the reduction of the overall risk of the chemical mixture. The overall human risk response to aquifer connectivity is shown to be nontrivial for multispecies transport. This nontriviality is a result of the interaction between aquifer heterogeneity and chemical toxicity. To quantify the joint effect of connectivity and toxicity in health risk, we propose a toxicity-based Damköhler number. Furthermore, we provide a statistical characterization in terms of low-order moments and the probability density function of the individual and total risks.

  17. EDCs Mixtures: A Stealthy Hazard for Human Health?

    PubMed

    Ribeiro, Edna; Ladeira, Carina; Viegas, Susana

    2017-02-07

    Endocrine disrupting chemicals (EDCs) are exogenous chemicals that may occur naturally (e.g., phytoestrogens), while others are industrial substances and plasticizers commonly utilized worldwide to which human exposure, particularly at low-doses, is omnipresent, persistent and occurs in complex mixtures. EDCs can interfere with/or mimic estrogenic hormones and, consequently, can simultaneously trigger diverse signaling pathways which result in diverse and divergent biological responses. Additionally, EDCs can also bioaccumulate in lipid compartments of the organism forming a mixed "body burden" of contaminants. Although the independent action of chemicals has been considered the main principle in EDCs mixture toxicity, recent studies have demonstrated that numerous effects cannot be predicted when analyzing single compounds independently. Co-exposure to these agents, particularly in critical windows of exposure, may induce hazardous health effects potentially associated with a complex "body burden" of different origins. Here, we performed an exhaustive review of the available literature regarding EDCs mixtures exposure, toxicity mechanisms and effects, particularly at the most vulnerable human life stages. Although the assessment of potential risks to human health due to exposure to EDCs mixtures is a major topic for consumer safety, information regarding effective mixtures effects is still scarce.

  18. EDCs Mixtures: A Stealthy Hazard for Human Health?

    PubMed Central

    Ribeiro, Edna; Ladeira, Carina; Viegas, Susana

    2017-01-01

    Endocrine disrupting chemicals (EDCs) are exogenous chemicals that may occur naturally (e.g., phytoestrogens), while others are industrial substances and plasticizers commonly utilized worldwide to which human exposure, particularly at low-doses, is omnipresent, persistent and occurs in complex mixtures. EDCs can interfere with/or mimic estrogenic hormones and, consequently, can simultaneously trigger diverse signaling pathways which result in diverse and divergent biological responses. Additionally, EDCs can also bioaccumulate in lipid compartments of the organism forming a mixed “body burden” of contaminants. Although the independent action of chemicals has been considered the main principle in EDCs mixture toxicity, recent studies have demonstrated that numerous effects cannot be predicted when analyzing single compounds independently. Co-exposure to these agents, particularly in critical windows of exposure, may induce hazardous health effects potentially associated with a complex “body burden” of different origins. Here, we performed an exhaustive review of the available literature regarding EDCs mixtures exposure, toxicity mechanisms and effects, particularly at the most vulnerable human life stages. Although the assessment of potential risks to human health due to exposure to EDCs mixtures is a major topic for consumer safety, information regarding effective mixtures effects is still scarce. PMID:29051438

  19. 40 CFR 91.1011 - Submission of exemption requests.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Exclusion and Exemption of Marine SI Engines § 91.1011 Submission of exemption requests. Requests for exemption or further information concerning exemptions and/or the exemption request review procedure should be addressed to: Manager, Engine...

  20. A Novel Approach for Evaluating Carbamate Mixtures for Dose Additivity

    EPA Science Inventory

    Two mathematical approaches were used to test the hypothesis ofdose-addition for a binary and a seven-chemical mixture ofN-methyl carbamates, toxicologically similar chemicals that inhibit cholinesterase (ChE). In the more novel approach, mixture data were not included in the ana...

  1. 45 CFR 2508.19 - What Privacy Act exemptions or control of systems of records are exempt from disclosure?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false What Privacy Act exemptions or control of systems of records are exempt from disclosure? 2508.19 Section 2508.19 Public Welfare Regulations Relating to... ACT OF 1974 § 2508.19 What Privacy Act exemptions or control of systems of records are exempt from...

  2. 40 CFR 180.341 - 2,4-Dinitro-6-octylphenyl crotonate and 2,6-dinitro-4-octylphenyl crotonate; tolerances for...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.341 2,4-Dinitro-6-octylphenyl... established for combined negligible residues of a fungicide and insecticide that is a mixture of 2,4-dinitro-6...

  3. 45 CFR 613.5 - Exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Exemptions. 613.5 Section 613.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION PRIVACY ACT REGULATIONS § 613.5 Exemptions. (a) Fellowships and other support. Pursuant to 5 U.S.C. 552a(k)(6), the Foundation hereby exempts from the application of 5 U.S.C...

  4. 10 CFR 1705.11 - Exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Exemptions. 1705.11 Section 1705.11 Energy DEFENSE NUCLEAR FACILITIES SAFETY BOARD PRIVACY ACT § 1705.11 Exemptions. Pursuant to 5 U.S.C. 552a(k), the Board has determined that system of records DNFSB-3, “Drug Testing Program Records,” is partially exempt from 5 U.S.C...

  5. 10 CFR 1705.11 - Exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Exemptions. 1705.11 Section 1705.11 Energy DEFENSE NUCLEAR FACILITIES SAFETY BOARD PRIVACY ACT § 1705.11 Exemptions. Pursuant to 5 U.S.C. 552a(k), the Board has determined that system of records DNFSB-3, “Drug Testing Program Records,” is partially exempt from 5 U.S.C...

  6. 10 CFR 1705.11 - Exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Exemptions. 1705.11 Section 1705.11 Energy DEFENSE NUCLEAR FACILITIES SAFETY BOARD PRIVACY ACT § 1705.11 Exemptions. Pursuant to 5 U.S.C. 552a(k), the Board has determined that system of records DNFSB-3, “Drug Testing Program Records,” is partially exempt from 5 U.S.C...

  7. 10 CFR 1705.11 - Exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Exemptions. 1705.11 Section 1705.11 Energy DEFENSE NUCLEAR FACILITIES SAFETY BOARD PRIVACY ACT § 1705.11 Exemptions. Pursuant to 5 U.S.C. 552a(k), the Board has determined that system of records DNFSB-3, “Drug Testing Program Records,” is partially exempt from 5 U.S.C...

  8. 75 FR 53867 - Additions to Listing of Exempt Chemical Mixtures

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-02

    ...% acetonitrile), dimethylformamide, ethylene glycol, isopropanol, methanol, methanol/water (50:50), methanol..., acetonitrile, acetonitrile: water (>= 50% acetonitrile), dimethylformamide, ethylene glycol, isopropanol...% acetonitrile), dimethylformamide, ethylene glycol, isopropanol, methanol, methanol/water (50:50), methanol...

  9. 40 CFR 91.1010 - Granting of exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Exclusion and Exemption of Marine SI Engines § 91.1010 Granting of exemptions. (a) If upon completion of the review of an exemption request... records accessible to EPA at reasonable times, employ labels for the exempt engines setting forth the...

  10. 40 CFR 92.908 - National security exemption.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false National security exemption. 92.908... Provisions § 92.908 National security exemption. A manufacturer or remanufacturer requesting a national security exemption must state the purpose for which the exemption is required and the request must be...

  11. 40 CFR 90.908 - National security exemption.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false National security exemption. 90.908... Exemption of Nonroad Engines from Regulations § 90.908 National security exemption. (a)(1) Any nonroad... defense, will be considered exempt from this part for purposes of national security. No request for...

  12. 29 CFR 541.708 - Combination exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... DELIMITING THE EXEMPTIONS FOR EXECUTIVE, ADMINISTRATIVE, PROFESSIONAL, COMPUTER AND OUTSIDE SALES EMPLOYEES Definitions and Miscellaneous Provisions § 541.708 Combination exemptions. Employees who perform a combination..., professional, outside sales and computer employees may qualify for exemption. Thus, for example, an employee...

  13. 29 CFR 541.708 - Combination exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... DELIMITING THE EXEMPTIONS FOR EXECUTIVE, ADMINISTRATIVE, PROFESSIONAL, COMPUTER AND OUTSIDE SALES EMPLOYEES Definitions and Miscellaneous Provisions § 541.708 Combination exemptions. Employees who perform a combination..., professional, outside sales and computer employees may qualify for exemption. Thus, for example, an employee...

  14. 29 CFR 541.708 - Combination exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... DELIMITING THE EXEMPTIONS FOR EXECUTIVE, ADMINISTRATIVE, PROFESSIONAL, COMPUTER AND OUTSIDE SALES EMPLOYEES Definitions and Miscellaneous Provisions § 541.708 Combination exemptions. Employees who perform a combination..., professional, outside sales and computer employees may qualify for exemption. Thus, for example, an employee...

  15. 29 CFR 541.708 - Combination exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... DELIMITING THE EXEMPTIONS FOR EXECUTIVE, ADMINISTRATIVE, PROFESSIONAL, COMPUTER AND OUTSIDE SALES EMPLOYEES Definitions and Miscellaneous Provisions § 541.708 Combination exemptions. Employees who perform a combination..., professional, outside sales and computer employees may qualify for exemption. Thus, for example, an employee...

  16. Evaluating exposures to complex mixtures of chemicals during a new production process in the plastics industry.

    PubMed

    Meijster, Tim; Burstyn, Igor; Van Wendel De Joode, Berna; Posthumus, Maarten A; Kromhout, Hans

    2004-08-01

    The goal of this study was to monitor emission of chemicals at a factory where plastics products were fabricated by a new robotic (impregnated tape winding) production process. Stationary and personal air measurements were taken to determine which chemicals were released and at what concentrations. Principal component analyses (PCA) and linear regression were used to determine the emission sources of different chemicals found in the air samples. We showed that complex mixtures of chemicals were released, but most concentrations were below Dutch exposure limits. Based on the results of the principal component analyses, the chemicals found were divided into three groups. The first group consisted of short chain aliphatic hydrocarbons (C2-C6). The second group included larger hydrocarbons (C9-C11) and some cyclic hydrocarbons. The third group contained all aromatic and two aliphatic hydrocarbons. Regression analyses showed that emission of the first group of chemicals was associated with cleaning activities and the use of epoxy resins. The second and third group showed strong association with the type of tape used in the new tape winding process. High levels of CO and HCN (above exposure limits) were measured on one occasion when a different brand of impregnated polypropylene sulphide tape was used in the tape winding process. Plans exist to drastically increase production with the new tape winding process. This will cause exposure levels to rise and therefore further control measures should be installed to reduce release of these chemicals.

  17. Composition of zeotropic mixtures having predefined temperature glide

    DOEpatents

    Mahmoud, Ahmad M.; Lee, Jaeseon; Luo, Dong

    2015-05-26

    A composition of a zeotropic mixture has a first chemical constituent and at least one second, different chemical constituent. The zeoptropic mixture has a temperature glide of 5.degree. C.-25.degree. C. with regard to its saturated vapor temperature and its saturated liquid temperature. The first chemical constituent is selected from 1,1,1,3,3-pentafluoropropane, 1,1,2,2,3-pentafluoropropane, 1,1,1,3,3-pentafluorobutane, methyl perfluoropropyl ether, 1,1,1,2,3,3-hexafluoropropane and 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone.

  18. Recognition of the Component Odors in Mixtures

    PubMed Central

    Fletcher, Dane B; Hettinger, Thomas P

    2017-01-01

    Abstract Natural olfactory stimuli are volatile-chemical mixtures in which relative perceptual saliencies determine which odor-components are identified. Odor identification also depends on rapid selective adaptation, as shown for 4 odor stimuli in an earlier experimental simulation of natural conditions. Adapt-test pairs of mixtures of water-soluble, distinct odor stimuli with chemical features in common were studied. Identification decreased for adapted components but increased for unadapted mixture-suppressed components, showing compound identities were retained, not degraded to individual molecular features. Four additional odor stimuli, 1 with 2 perceptible odor notes, and an added “water-adapted” control tested whether this finding would generalize to other 4-compound sets. Selective adaptation of mixtures of the compounds (odors): 3 mM benzaldehyde (cherry), 5 mM maltol (caramel), 1 mM guaiacol (smoke), and 4 mM methyl anthranilate (grape-smoke) again reciprocally unmasked odors of mixture-suppressed components in 2-, 3-, and 4-component mixtures with 2 exceptions. The cherry note of “benzaldehyde” (itself) and the shared note of “methyl anthranilate and guaiacol” (together) were more readily identified. The pervasive mixture-component dominance and dynamic perceptual salience may be mediated through peripheral adaptation and central mutual inhibition of neural responses. Originating in individual olfactory receptor variants, it limits odor identification and provides analytic properties for momentary recognition of a few remaining mixture-components. PMID:28641388

  19. Adverse Reproductive and Developmental Health Outcomes Following Prenatal Exposure to a Hydraulic Fracturing Chemical Mixture in Female C57Bl/6 Mice.

    PubMed

    Kassotis, Christopher D; Bromfield, John J; Klemp, Kara C; Meng, Chun-Xia; Wolfe, Andrew; Zoeller, R Thomas; Balise, Victoria D; Isiguzo, Chiamaka J; Tillitt, Donald E; Nagel, Susan C

    2016-09-01

    Unconventional oil and gas operations using hydraulic fracturing can contaminate surface and groundwater with endocrine-disrupting chemicals. We have previously shown that 23 of 24 commonly used hydraulic fracturing chemicals can activate or inhibit the estrogen, androgen, glucocorticoid, progesterone, and/or thyroid receptors in a human endometrial cancer cell reporter gene assay and that mixtures can behave synergistically, additively, or antagonistically on these receptors. In the current study, pregnant female C57Bl/6 dams were exposed to a mixture of 23 commonly used unconventional oil and gas chemicals at approximately 3, 30, 300, and 3000 μg/kg·d, flutamide at 50 mg/kg·d, or a 0.2% ethanol control vehicle via their drinking water from gestational day 11 through birth. This prenatal exposure to oil and gas operation chemicals suppressed pituitary hormone concentrations across experimental groups (prolactin, LH, FSH, and others), increased body weights, altered uterine and ovary weights, increased heart weights and collagen deposition, disrupted folliculogenesis, and other adverse health effects. This work suggests potential adverse developmental and reproductive health outcomes in humans and animals exposed to these oil and gas operation chemicals, with adverse outcomes observed even in the lowest dose group tested, equivalent to concentrations reported in drinking water sources. These endpoints suggest potential impacts on fertility, as previously observed in the male siblings, which require careful assessment in future studies.

  20. Adverse Reproductive and Developmental Health Outcomes Following Prenatal Exposure to a Hydraulic Fracturing Chemical Mixture in Female C57Bl/6 Mice

    PubMed Central

    Kassotis, Christopher D.; Bromfield, John J.; Klemp, Kara C.; Meng, Chun-Xia; Wolfe, Andrew; Zoeller, R. Thomas; Balise, Victoria D.; Isiguzo, Chiamaka J.; Tillitt, Donald E.

    2016-01-01

    Unconventional oil and gas operations using hydraulic fracturing can contaminate surface and groundwater with endocrine-disrupting chemicals. We have previously shown that 23 of 24 commonly used hydraulic fracturing chemicals can activate or inhibit the estrogen, androgen, glucocorticoid, progesterone, and/or thyroid receptors in a human endometrial cancer cell reporter gene assay and that mixtures can behave synergistically, additively, or antagonistically on these receptors. In the current study, pregnant female C57Bl/6 dams were exposed to a mixture of 23 commonly used unconventional oil and gas chemicals at approximately 3, 30, 300, and 3000 μg/kg·d, flutamide at 50 mg/kg·d, or a 0.2% ethanol control vehicle via their drinking water from gestational day 11 through birth. This prenatal exposure to oil and gas operation chemicals suppressed pituitary hormone concentrations across experimental groups (prolactin, LH, FSH, and others), increased body weights, altered uterine and ovary weights, increased heart weights and collagen deposition, disrupted folliculogenesis, and other adverse health effects. This work suggests potential adverse developmental and reproductive health outcomes in humans and animals exposed to these oil and gas operation chemicals, with adverse outcomes observed even in the lowest dose group tested, equivalent to concentrations reported in drinking water sources. These endpoints suggest potential impacts on fertility, as previously observed in the male siblings, which require careful assessment in future studies. PMID:27560547

  1. 40 CFR 166.45 - Duration of crisis exemption.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Duration of crisis exemption. 166.45... EXEMPTION OF FEDERAL AND STATE AGENCIES FOR USE OF PESTICIDES UNDER EMERGENCY CONDITIONS Crisis Exemptions § 166.45 Duration of crisis exemption. A crisis exemption may be authorized for: (a) Only as long as is...

  2. Improving Students' Understanding of the Connections between the Concepts of Real-Gas Mixtures, Gas Ideal-Solutions, and Perfect-Gas Mixtures

    ERIC Educational Resources Information Center

    Privat, Romain; Jaubert, Jean-Noël; Moine, Edouard

    2016-01-01

    In many textbooks of chemical-engineering thermodynamics, a gas mixture obeying the fundamental law pV[subscript m] = RT is most often called ideal-gas mixture (in some rare cases, the term perfect-gas mixture can be found). These textbooks also define the fundamental concept of ideal solution which in theory, can be applied indifferently to…

  3. Extending the Distributed Lag Model framework to handle chemical mixtures.

    PubMed

    Bello, Ghalib A; Arora, Manish; Austin, Christine; Horton, Megan K; Wright, Robert O; Gennings, Chris

    2017-07-01

    Distributed Lag Models (DLMs) are used in environmental health studies to analyze the time-delayed effect of an exposure on an outcome of interest. Given the increasing need for analytical tools for evaluation of the effects of exposure to multi-pollutant mixtures, this study attempts to extend the classical DLM framework to accommodate and evaluate multiple longitudinally observed exposures. We introduce 2 techniques for quantifying the time-varying mixture effect of multiple exposures on an outcome of interest. Lagged WQS, the first technique, is based on Weighted Quantile Sum (WQS) regression, a penalized regression method that estimates mixture effects using a weighted index. We also introduce Tree-based DLMs, a nonparametric alternative for assessment of lagged mixture effects. This technique is based on the Random Forest (RF) algorithm, a nonparametric, tree-based estimation technique that has shown excellent performance in a wide variety of domains. In a simulation study, we tested the feasibility of these techniques and evaluated their performance in comparison to standard methodology. Both methods exhibited relatively robust performance, accurately capturing pre-defined non-linear functional relationships in different simulation settings. Further, we applied these techniques to data on perinatal exposure to environmental metal toxicants, with the goal of evaluating the effects of exposure on neurodevelopment. Our methods identified critical neurodevelopmental windows showing significant sensitivity to metal mixtures. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Notification: Evaluation of EPA’s Federal Insecticide, Fungicide, and Rodenticide Act Section 18 Emergency Exemptions

    EPA Pesticide Factsheets

    Project #OPE-FY17-0024, August 21, 2017. The EPA OIG plans to begin preliminary research on the emergency exemption process used by the EPA’s Office of Chemical Safety and Pollution Prevention’s Office of Pesticide Programs.

  5. 17 CFR 250.3 - Exemption of certain banks.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Exemption of certain banks... Exemptions § 250.3 Exemption of certain banks. (a) General exemption. Subject to the provisions of § 250.6 and to the requirements contained in paragraph (c) of this section, any bank shall be exempt from any...

  6. 32 CFR 319.13 - Specific exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... name: LDIA 0900, Accounts Receivable, Indebtedness and Claims. (1) Exemption: During the course of accounts receivable, indebtedness or claims actions, exempt materials from other systems of records may in... Liberties Case Management System. (1) Exemptions: Any portion of this record system which falls within the...

  7. Supersonic flow of chemically reacting gas-particle mixtures. Volume 1: A theoretical analysis and development of the numerical solution

    NASA Technical Reports Server (NTRS)

    Penny, M. M.; Smith, S. D.; Anderson, P. G.; Sulyma, P. R.; Pearson, M. L.

    1976-01-01

    A numerical solution for chemically reacting supersonic gas-particle flows in rocket nozzles and exhaust plumes was described. The gas-particle flow solution is fully coupled in that the effects of particle drag and heat transfer between the gas and particle phases are treated. Gas and particles exchange momentum via the drag exerted on the gas by the particles. Energy is exchanged between the phases via heat transfer (convection and/or radiation). Thermochemistry calculations (chemical equilibrium, frozen or chemical kinetics) were shown to be uncoupled from the flow solution and, as such, can be solved separately. The solution to the set of governing equations is obtained by utilizing the method of characteristics. The equations cast in characteristic form are shown to be formally the same for ideal, frozen, chemical equilibrium and chemical non-equilibrium reacting gas mixtures. The particle distribution is represented in the numerical solution by a finite distribution of particle sizes.

  8. 29 CFR 784.117 - Combinations of exempt work.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Combinations of exempt work. 784.117 Section 784.117 Labor... Aquatic Products Principles Applicable to the Two Exemptions § 784.117 Combinations of exempt work. The combination of exempt work under sections 13(a)(5) and 13(b)(4), or one of these sections with exempt work...

  9. 7 CFR 922.110 - Container exemption.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Container exemption. 922.110 Section 922.110... COUNTIES IN WASHINGTON Container Exemption; Waivers of Inspection and Certification § 922.110 Container exemption. Whenever container limitations are effective pursuant to § 922.52, a handler may make test...

  10. 32 CFR 323.6 - Exemption rules.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... DEFENSE LOGISTICS AGENCY PRIVACY PROGRAM § 323.6 Exemption rules. (a) The Director, DLA or designee may... proceedings. (c) Exempt Records Systems. All systems of records maintained by the Defense Logistics Agency... Identifier: S500.20 (Specific exemption). (1) System name: Defense Logistics Agency (DLA) Criminal Incident...

  11. 32 CFR 323.6 - Exemption rules.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... DEFENSE LOGISTICS AGENCY PRIVACY PROGRAM § 323.6 Exemption rules. (a) The Director, DLA or designee may... proceedings. (c) Exempt Records Systems. All systems of records maintained by the Defense Logistics Agency... Identifier: S500.20 (Specific exemption). (1) System name: Defense Logistics Agency (DLA) Criminal Incident...

  12. 29 CFR 2580.412-29 - Exemption.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Exemptions Savings and Loan Associations Subject to Federal Regulation § 2580.412-29 Exemption. An exemption... Act is granted whereby savings and loan associations (including building and loan associations... for the benefit of their own employees, where such a savings and loan association is the administrator...

  13. 11 CFR 2.4 - Exempted meetings.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 11 Federal Elections 1 2010-01-01 2010-01-01 false Exempted meetings. 2.4 Section 2.4 Federal Elections FEDERAL ELECTION COMMISSION SUNSHINE REGULATIONS; MEETINGS § 2.4 Exempted meetings. (a) Meetings required by statute to be closed. Meetings concerning matters specifically exempted from disclosure by...

  14. 40 CFR 180.1019 - Sulfuric acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... good agricultural practice when used as a herbicide in the production of garlic and onions, and as a... from the use of sulfuric acid as an inert ingredient in a pesticide product used in irrigation...

  15. 40 CFR 180.1225 - Decanoic acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., breweries, wineries, beverage and food processing plants. [68 FR 7939, Feb. 19, 2003; 68 FR 17308, Apr. 9... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... acid (up to 170 ppm per application) on food contact surfaces such as equipment, pipelines, tanks, vats...

  16. 10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... natural gas or petroleum. 503.38 Section 503.38 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS... mixtures containing natural gas or petroleum. (a) Eligibility. Section 212(d) of the Act provides for a... proposes to use a mixture of natural gas or petroleum and an alternate fuel as a primary energy source; (2...

  17. 48 CFR 408.706 - Purchase exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Purchase exemptions. 408... People Who Are Blind or Severely Disabled 408.706 Purchase exemptions. Prior to applying to the Committee for a purchase exemption, the chief of the contracting office should provide advance notice to the...

  18. 18 CFR 420.43 - Exempt use.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Exempt use. 420.43 Section 420.43 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Charges; Exemptions § 420.43 Exempt use. The following uses...

  19. 18 CFR 420.43 - Exempt use.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Exempt use. 420.43 Section 420.43 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Charges; Exemptions § 420.43 Exempt use. The following uses...

  20. 18 CFR 420.43 - Exempt use.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Exempt use. 420.43 Section 420.43 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Charges; Exemptions § 420.43 Exempt use. The following uses...

  1. 18 CFR 420.43 - Exempt use.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Exempt use. 420.43 Section 420.43 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Charges; Exemptions § 420.43 Exempt use. The following uses...

  2. 18 CFR 420.43 - Exempt use.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Exempt use. 420.43 Section 420.43 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Charges; Exemptions § 420.43 Exempt use. The following uses...

  3. 10 CFR 54.15 - Specific exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Specific exemptions. 54.15 Section 54.15 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) REQUIREMENTS FOR RENEWAL OF OPERATING LICENSES FOR NUCLEAR POWER PLANTS General Provisions § 54.15 Specific exemptions. Exemptions from the requirements of this part may be...

  4. 14 CFR 298.11 - Exemption authority.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... REGULATIONS EXEMPTIONS FOR AIR TAXI AND COMMUTER AIR CARRIER OPERATIONS Exemptions § 298.11 Exemption authority. Air taxi operators and commuter air carriers are hereby relieved from the following provisions of... imposed herein, and to the extent necessary to permit them to conduct air taxi or commuter air carrier...

  5. 14 CFR 298.11 - Exemption authority.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... REGULATIONS EXEMPTIONS FOR AIR TAXI AND COMMUTER AIR CARRIER OPERATIONS Exemptions § 298.11 Exemption authority. Air taxi operators and commuter air carriers are hereby relieved from the following provisions of... imposed herein, and to the extent necessary to permit them to conduct air taxi or commuter air carrier...

  6. Concentration Addition, Independent Action and Generalized Concentration Addition Models for Mixture Effect Prediction of Sex Hormone Synthesis In Vitro

    PubMed Central

    Hadrup, Niels; Taxvig, Camilla; Pedersen, Mikael; Nellemann, Christine; Hass, Ulla; Vinggaard, Anne Marie

    2013-01-01

    Humans are concomitantly exposed to numerous chemicals. An infinite number of combinations and doses thereof can be imagined. For toxicological risk assessment the mathematical prediction of mixture effects, using knowledge on single chemicals, is therefore desirable. We investigated pros and cons of the concentration addition (CA), independent action (IA) and generalized concentration addition (GCA) models. First we measured effects of single chemicals and mixtures thereof on steroid synthesis in H295R cells. Then single chemical data were applied to the models; predictions of mixture effects were calculated and compared to the experimental mixture data. Mixture 1 contained environmental chemicals adjusted in ratio according to human exposure levels. Mixture 2 was a potency adjusted mixture containing five pesticides. Prediction of testosterone effects coincided with the experimental Mixture 1 data. In contrast, antagonism was observed for effects of Mixture 2 on this hormone. The mixtures contained chemicals exerting only limited maximal effects. This hampered prediction by the CA and IA models, whereas the GCA model could be used to predict a full dose response curve. Regarding effects on progesterone and estradiol, some chemicals were having stimulatory effects whereas others had inhibitory effects. The three models were not applicable in this situation and no predictions could be performed. Finally, the expected contributions of single chemicals to the mixture effects were calculated. Prochloraz was the predominant but not sole driver of the mixtures, suggesting that one chemical alone was not responsible for the mixture effects. In conclusion, the GCA model seemed to be superior to the CA and IA models for the prediction of testosterone effects. A situation with chemicals exerting opposing effects, for which the models could not be applied, was identified. In addition, the data indicate that in non-potency adjusted mixtures the effects cannot always be

  7. 40 CFR 180.1027 - Nuclear polyhedrosis virus of Heliothis zea; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1027 Nuclear polyhedrosis virus of... should not exceed 107 colonies per gram as determined by an aerobic plate on trypticase soy agar. (2...

  8. 40 CFR 180.1027 - Nuclear polyhedrosis virus of Heliothis zea; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1027 Nuclear polyhedrosis virus of... should not exceed 107 colonies per gram as determined by an aerobic plate on trypticase soy agar. (2...

  9. 18 CFR 401.112 - Exempt information.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Exempt information. 401... ADMINISTRATIVE MANUAL RULES OF PRACTICE AND PROCEDURE Public Access to Records and Information § 401.112 Exempt information. The following materials and information covered by this part shall be exempt from disclosure...

  10. 10 CFR 26.9 - Specific exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Specific exemptions. 26.9 Section 26.9 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Administrative Provisions § 26.9 Specific exemptions. Upon application of any interested person or on its own initiative, the Commission may grant such exemptions from...

  11. 10 CFR 26.9 - Specific exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Specific exemptions. 26.9 Section 26.9 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Administrative Provisions § 26.9 Specific exemptions. Upon application of any interested person or on its own initiative, the Commission may grant such exemptions from...

  12. 50 CFR 660.516 - Exempted fishing.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Exempted fishing. 660.516 Section 660.516... Exempted fishing. (a) General. In the interest of developing an efficient and productive fishery for CPS, the Regional Administrator may issue exempted fishing permits (EFP) for the harvest of CPS that...

  13. 50 CFR 660.718 - Exempted fishing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Exempted fishing. 660.718 Section 660.718... Exempted fishing. (a) In the interest of developing an efficient and productive fishery for HMS, the Regional Administrator may issue exempted fishing permits (EFP) for the harvest of HMS that otherwise would...

  14. 50 CFR 660.516 - Exempted fishing.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Exempted fishing. 660.516 Section 660.516... Exempted fishing. (a) General. In the interest of developing an efficient and productive fishery for CPS, the Regional Administrator may issue exempted fishing permits (EFP) for the harvest of CPS that...

  15. 50 CFR 660.718 - Exempted fishing.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Exempted fishing. 660.718 Section 660.718... Exempted fishing. (a) In the interest of developing an efficient and productive fishery for HMS, the Regional Administrator may issue exempted fishing permits (EFP) for the harvest of HMS that otherwise would...

  16. 50 CFR 660.516 - Exempted fishing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Exempted fishing. 660.516 Section 660.516... Exempted fishing. (a) General. In the interest of developing an efficient and productive fishery for CPS, the Regional Administrator may issue exempted fishing permits (EFP) for the harvest of CPS that...

  17. 50 CFR 660.718 - Exempted fishing.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Exempted fishing. 660.718 Section 660.718... Exempted fishing. (a) In the interest of developing an efficient and productive fishery for HMS, the Regional Administrator may issue exempted fishing permits (EFP) for the harvest of HMS that otherwise would...

  18. 50 CFR 660.718 - Exempted fishing.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Exempted fishing. 660.718 Section 660.718... Exempted fishing. (a) In the interest of developing an efficient and productive fishery for HMS, the Regional Administrator may issue exempted fishing permits (EFP) for the harvest of HMS that otherwise would...

  19. 50 CFR 660.516 - Exempted fishing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Exempted fishing. 660.516 Section 660.516... Exempted fishing. (a) General. In the interest of developing an efficient and productive fishery for CPS, the Regional Administrator may issue exempted fishing permits (EFP) for the harvest of CPS that...

  20. 50 CFR 660.718 - Exempted fishing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Exempted fishing. 660.718 Section 660.718... Exempted fishing. (a) In the interest of developing an efficient and productive fishery for HMS, the Regional Administrator may issue exempted fishing permits (EFP) for the harvest of HMS that otherwise would...

  1. 10 CFR 55.13 - General exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 2 2014-01-01 2014-01-01 false General exemptions. 55.13 Section 55.13 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) OPERATORS' LICENSES Exemptions § 55.13 General exemptions. The regulations in this part do not require a license for an individual who— (a) Under the direction and in the...

  2. 18 CFR 401.112 - Exempt information.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Exempt information. 401... ADMINISTRATIVE MANUAL RULES OF PRACTICE AND PROCEDURE Public Access to Records and Information § 401.112 Exempt information. The following materials and information covered by this part shall be exempt from disclosure...

  3. 10 CFR 26.9 - Specific exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Specific exemptions. 26.9 Section 26.9 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Administrative Provisions § 26.9 Specific exemptions. Upon application of any interested person or on its own initiative, the Commission may grant such exemptions from...

  4. 10 CFR 26.9 - Specific exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Specific exemptions. 26.9 Section 26.9 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Administrative Provisions § 26.9 Specific exemptions. Upon application of any interested person or on its own initiative, the Commission may grant such exemptions from...

  5. 10 CFR 26.9 - Specific exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Specific exemptions. 26.9 Section 26.9 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Administrative Provisions § 26.9 Specific exemptions. Upon application of any interested person or on its own initiative, the Commission may grant such exemptions from...

  6. 10 CFR 55.13 - General exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false General exemptions. 55.13 Section 55.13 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) OPERATORS' LICENSES Exemptions § 55.13 General exemptions. The regulations in this part do not require a license for an individual who— (a) Under the direction and in the...

  7. Susceptibility of Microsporum canis arthrospores to a mixture of chemically defined essential oils: a perspective for environmental decontamination.

    PubMed

    Nardoni, Simona; Tortorano, Annamaria; Mugnaini, Linda; Profili, Greta; Pistelli, Luisa; Giovanelli, Silvia; Pisseri, Francesca; Papini, Roberto; Mancianti, Francesca

    2015-01-01

    The zoophilic dermatophyte Microsporum canis has cats as natural reservoir, but it is able to infect a wide range of hosts, including humans, where different clinical features of the so-called ringworm dermatophytosis have been described. Human infections are increasingly been reported in Mediterranean countries. A reliable control program against M. canis infection in cats should include an antifungal treatment of both the infected animals and their living environment. In this article, a herbal mixture composed of chemically defined essential oils (EOs) of Litsea cubeba (1%), Illicium verum, Foeniculum vulgare, and Pelargonium graveolens (0.5% each) was formulated and its antifungal activity assessed against M. canis arthrospores which represent the infective environmental stage of M. canis. Single compounds present in higher amounts in the mixture were also separately tested in vitro. Litsea cubeba and P. graveolens EOs were most effective (minimum inhibitory concentration (MIC) 0.5%), followed by EOs of I. verum (MIC 2%) and F. vulgare (MIC 2.5%). Minimum fungicidal concentrations (MFC) values were 0.75% (L. cubeba), 1.5% (P. graveolens), 2.5% (I. verum) and 3% (F. vulgare). MIC and MFC values of the mixture were 0.25% and 0.5%, respectively. The daily spray of the mixture (200 μL) directly onto infected hairs inhibited fungal growth from the fourth day onwards. The compounds present in higher amounts exhibited variable antimycotic activity, with MIC values ranging from >10% (limonene) to 0.1% (geranial and neral). Thus, the mixture showed a good antifungal activity against arthrospores present in infected hairs. These results are promising for a further application of the mixture as an alternative tool or as an adjuvant in the environmental control of feline microsporosis.

  8. 21 CFR 21.61 - Exempt systems.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Exempt systems. 21.61 Section 21.61 Food and Drugs... Exemptions § 21.61 Exempt systems. (a) Investigatory records compiled for law enforcement purposes, including criminal law enforcement purposes, in the Food and Drug Administration Privacy Act Record Systems listed in...

  9. 21 CFR 21.61 - Exempt systems.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Exempt systems. 21.61 Section 21.61 Food and Drugs... Exemptions § 21.61 Exempt systems. (a) Investigatory records compiled for law enforcement purposes, including criminal law enforcement purposes, in the Food and Drug Administration Privacy Act Record Systems listed in...

  10. 40 CFR 92.909 - Export exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Export exemptions. 92.909 Section 92....909 Export exemptions. (a) A new locomotive or locomotive engine intended solely for export, and so... from EPA standards. (c) It is a condition of any exemption for the purpose of export under paragraph (a...

  11. 40 CFR 180.1189 - Methyl salicylate; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... food or feed when used as an insect repellant in food packaging and animal feed packaging at an application rate that does not exceed 0.2 mg of methyl salicylate per square inch of packaging materials. [62... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD...

  12. 40 CFR 180.1189 - Methyl salicylate; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... food or feed when used as an insect repellant in food packaging and animal feed packaging at an application rate that does not exceed 0.2 mg of methyl salicylate per square inch of packaging materials. [62... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD...

  13. 40 CFR 180.1189 - Methyl salicylate; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... food or feed when used as an insect repellant in food packaging and animal feed packaging at an application rate that does not exceed 0.2 mg of methyl salicylate per square inch of packaging materials. [62... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD...

  14. 40 CFR 180.1189 - Methyl salicylate; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... food or feed when used as an insect repellant in food packaging and animal feed packaging at an application rate that does not exceed 0.2 mg of methyl salicylate per square inch of packaging materials. [62... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD...

  15. 40 CFR 180.1189 - Methyl salicylate; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... food or feed when used as an insect repellant in food packaging and animal feed packaging at an application rate that does not exceed 0.2 mg of methyl salicylate per square inch of packaging materials. [62... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD...

  16. Prenatal Exposure to Unconventional Oil and Gas Operation Chemical Mixtures Altered Mammary Gland Development in Adult Female Mice.

    PubMed

    Sapouckey, Sarah A; Kassotis, Christopher D; Nagel, Susan C; Vandenberg, Laura N

    2018-03-01

    Unconventional oil and gas (UOG) operations, which combine hydraulic fracturing (fracking) and directional drilling, involve the use of hundreds of chemicals, including many with endocrine-disrupting properties. Two previous studies examined mice exposed during early development to a 23-chemical mixture of UOG compounds (UOG-MIX) commonly used or produced in the process. Both male and female offspring exposed prenatally to one or more doses of UOG-MIX displayed alterations to endocrine organ function and serum hormone concentrations. We hypothesized that prenatal UOG-MIX exposure would similarly disrupt development of the mouse mammary gland. Female C57Bl/6 mice were exposed to ~3, ~30, ~ 300, or ~3000 μg/kg/d UOG-MIX from gestational day 11 to birth. Although no effects were observed on the mammary glands of these females before puberty, in early adulthood, females exposed to 300 or 3000 μg/kg/d UOG-MIX developed more dense mammary epithelial ducts; females exposed to 3 μg/kg/d UOG-MIX had an altered ratio of apoptosis to proliferation in the mammary epithelium. Furthermore, adult females from all UOG-MIX-treated groups developed intraductal hyperplasia that resembled terminal end buds (i.e., highly proliferative structures typically seen at puberty). These results suggest that the mammary gland is sensitive to mixtures of chemicals used in UOG production at exposure levels that are environmentally relevant. The effect of these findings on the long-term health of the mammary gland, including its lactational capacity and its risk of cancer, should be evaluated in future studies. Copyright © 2018 Endocrine Society.

  17. 20 CFR 401.85 - Exempt systems.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Exempt systems. 401.85 Section 401.85... INFORMATION The Privacy Act § 401.85 Exempt systems. (a) General policy. The Privacy Act permits certain types of specific systems of records to be exempt from some of its requirements. Our policy is to exercise...

  18. 40 CFR 94.909 - Export exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Export exemptions. 94.909 Section 94... Export exemptions. (a) A new engine intended solely for export, and so labeled or tagged on the outside... of export under paragraph (a) of this section, that such exemption is void ab initio with respect to...

  19. 29 CFR 780.329 - Exempt work.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Exempt work. 780.329 Section 780.329 Labor Regulations... Provisions § 780.329 Exempt work. (a) The standard that must be used to determine whether the individual...) Thus, exempt work must be performed away from the “headquarters.” The headquarters is not, however, to...

  20. 29 CFR 780.329 - Exempt work.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Exempt work. 780.329 Section 780.329 Labor Regulations... Provisions § 780.329 Exempt work. (a) The standard that must be used to determine whether the individual...) Thus, exempt work must be performed away from the “headquarters.” The headquarters is not, however, to...

  1. 20 CFR 401.85 - Exempt systems.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Exempt systems. 401.85 Section 401.85... INFORMATION The Privacy Act § 401.85 Exempt systems. (a) General policy. The Privacy Act permits certain types of specific systems of records to be exempt from some of its requirements. Our policy is to exercise...

  2. 75 FR 66423 - Qualification of Drivers; Exemption Applications; Vision

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-28

    ... renewal of exemptions; request for comments. SUMMARY: FMCSA announces its decision to renew the exemptions... the exemptions for these commercial motor vehicle (CMV) drivers. DATES: This decision is effective... exemption (including renewals) are set out in 49 CFR part 381. Exemption Decision This notice addresses 13...

  3. 49 CFR 381.300 - What is an exemption?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 5 2012-10-01 2012-10-01 false What is an exemption? 381.300 Section 381.300 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY... PILOT PROGRAMS Procedures for Applying for Exemptions § 381.300 What is an exemption? (a) An exemption...

  4. 49 CFR 381.300 - What is an exemption?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false What is an exemption? 381.300 Section 381.300 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY... PILOT PROGRAMS Procedures for Applying for Exemptions § 381.300 What is an exemption? (a) An exemption...

  5. 49 CFR 381.300 - What is an exemption?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false What is an exemption? 381.300 Section 381.300 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY... PILOT PROGRAMS Procedures for Applying for Exemptions § 381.300 What is an exemption? (a) An exemption...

  6. Research and Guidance on Drinking Water Contaminant Mixtures

    EPA Science Inventory

    Accurate assessment of potential human health risk(s) from multiple-route exposures to multiple chemicals in drinking water is needed because of widespread daily exposure to this complex mixture. Hundreds of chemicals have been identified in drinking water with the mix of chemic...

  7. Solid-phase microextraction low temperature plasma mass spectrometry for the direct and rapid analysis of chemical warfare simulants in complex mixtures.

    PubMed

    Dumlao, Morphy C; Jeffress, Laura E; Gooding, J Justin; Donald, William A

    2016-06-21

    Solid-phase microextraction (SPME) is directly integrated with low temperature plasma ionisation mass spectrometry to rapidly detect organophosphate chemical warfare agent simulants and their hydrolysis products in chemical mixtures, including urine. In this sampling and ionization method, the fibre serves: (i) to extract molecules from their native environment, and (ii) as the ionization electrode that is used to desorb and ionize molecules directly from the SPME surface. By use of a custom fabricated SPME fibre consisting of a stainless steel needle coated with a Linde Type A (LTA) zeolitic microporous material and low temperature plasma mass spectrometry, protonated dimethyl methylphosphonate (DMMP), diethyl ethylphosphonate (DEEP) and pinacolyl methylphosphonic acid (PinMPA) can be detected at less than 100 ppb directly in water and urine. Organophosphates were not readily detected by this approach using an uncoated needle in negative control experiments. The use of the LTA coating significantly outperformed the use of a high alumina Zeolite Socony Mobil-5 (ZSM-5) coating of comparable thickness that is significantly less polar than LTA. By conditioning the LTA probe by immersion in an aqueous CuSO4 solution, the ion abundance for protonated DMMP increased by more than 300% compared to that obtained without any conditioning. Sample recovery values were between 96 and 100% for each analyte. The detection of chemical warfare agent analogues and hydrolysis products required less than 2 min per sample. A key advantage of this sampling and ionization method is that analyte ions can be directly and rapidly sampled from chemical mixtures, such as urine and seawater, without sample preparation or chromatography for sensitive detection by mass spectrometry. This ion source should prove beneficial for portable mass spectrometry applications because relatively low detection limits can be obtained without the use of compressed gases, fluid pumps, and lasers. Moreover, the

  8. Shock wave induced condensation in fuel-rich gaseous and gas-particles mixtures

    NASA Astrophysics Data System (ADS)

    Fomin, P. A.

    2018-03-01

    The possibility of fuel vapor condensation in shock waves in fuel-rich (cyclohexane-oxygen) gaseous mixtures and explosion safety aspects of this effect are discussed. It is shown, that condensation process can essentially change the chemical composition of the gas. For example, the molar fraction of the oxidizer can increase in a few times. As a result, mixtures in which the initial concentration of fuel vapor exceeds the Upper Flammability Limit can, nevertheless, explode, if condensation shifts the composition of the mixture into the ignition region. The rate of the condensation process is estimated. This process can be fast enough to significantly change the chemical composition of the gas and shift it into the flammable range during the compression phase of blast waves, generated by explosions of fuel-vapor clouds or rapture of pressurized chemical reactors, with characteristic size of a few meters. It is shown that the presence of chemically inert microparticles in the gas mixtures under consideration increases the degree of supercooling and the mass of fuel vapors that have passed into the liquid and reduces the characteristic condensation time in comparison with the gas mixture without microparticles. The fuel vapor condensation should be taken into account in estimation the explosion hazard of chemical reactors, industrial and civil constructions, which may contain fuel-rich gaseous mixtures of heavy hydrocarbons with air.

  9. 17 CFR 247.775 - Exemption from the definition of “broker” for banks effecting certain excepted or exempted...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Exemption from the definition of âbrokerâ for banks effecting certain excepted or exempted transactions in investment company... (CONTINUED) REGULATION R-EXEMPTIONS AND DEFINITIONS RELATED TO THE EXCEPTIONS FOR BANKS FROM THE DEFINITION...

  10. ThermoData Engine Database - Pure Compounds and Binary Mixtures

    National Institute of Standards and Technology Data Gateway

    SRD 103b NIST ThermoData Engine Version 6.0 - Pure CompoThermoData Engine Database - Pure Compounds and Binary Mixtures (PC database for purchase)   This database contains property data for more than 21,000 pure compounds, 37,500 binary mixtures, 10,000 ternary mixtures, and 6,000 chemical reactions.

  11. Conditional admission, religious exemption type, and nonmedical vaccine exemptions in California before and after a state policy change.

    PubMed

    Buttenheim, Alison M; Jones, Malia; Mckown, Caitlin; Salmon, Daniel; Omer, Saad B

    2018-06-18

    Recent measles and pertussis outbreaks in the US have focused national attention on state laws governing exemptions from mandatory vaccines for school entry. After several years of increases in nonmedical exemptions in California, the state assembly passed Assembly Bill 2109 in 2012, making nonmedical exemptions more difficult to obtain by requiring parents to obtain a signature from a health care provider. We used data from the California Department of Public Health to describe changes in the overall prevalence of personal belief exemptions and compositional changes in immunization status for the school years 2012-2013 through 2015-2016. Following the implementation of Assembly Bill 2109, the statewide exemption rate declined from 3.1% in 2013 to 2.5% in 2014 and then to 2.3% in 2015, representing a 25% reduction from the 2013 peak. Continued surveillance of exemption rates and vaccine refusal are needed to monitor and protect herd immunity against vaccine-preventable diseases. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. 29 CFR 793.21 - Exempt and nonexempt work.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Exempt and nonexempt work. 793.21 Section 793.21 Labor... POLICY OR INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS EXEMPTION OF CERTAIN RADIO AND TELEVISION... Workweek Application of Exemption § 793.21 Exempt and nonexempt work. Where an employee in the same...

  13. 41 CFR 101-39.106 - Unlimited exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-INTERAGENCY FLEET MANAGEMENT SYSTEMS 39.1-Establishment, Modification, and Discontinuance of Interagency Fleet Management Systems § 101-39.106 Unlimited exemptions. Unlimited exemptions from inclusion in the fleet... below. Unlimited exemptions do not preclude agencies from requesting fleet management services, if...

  14. 19 CFR 148.53 - Exemption for tools of trade.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 2 2012-04-01 2012-04-01 false Exemption for tools of trade. 148.53 Section 148.53 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) PERSONAL DECLARATIONS AND EXEMPTIONS Other Exemptions § 148.53 Exemption for tools of trade. (a) Exemption. Professional...

  15. 19 CFR 148.53 - Exemption for tools of trade.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 2 2013-04-01 2013-04-01 false Exemption for tools of trade. 148.53 Section 148.53 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) PERSONAL DECLARATIONS AND EXEMPTIONS Other Exemptions § 148.53 Exemption for tools of trade. (a) Exemption. Professional...

  16. 19 CFR 148.53 - Exemption for tools of trade.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Exemption for tools of trade. 148.53 Section 148.53 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) PERSONAL DECLARATIONS AND EXEMPTIONS Other Exemptions § 148.53 Exemption for tools of trade. (a) Exemption. Professional...

  17. 19 CFR 148.53 - Exemption for tools of trade.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 2 2011-04-01 2011-04-01 false Exemption for tools of trade. 148.53 Section 148.53 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) PERSONAL DECLARATIONS AND EXEMPTIONS Other Exemptions § 148.53 Exemption for tools of trade. (a) Exemption. Professional...

  18. 17 CFR 250.3 - Exemption of certain banks.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... this section, means any company primarily engaged in business as a commercial bank or trust company, or... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Exemption of certain banks... Exemptions § 250.3 Exemption of certain banks. (a) General exemption. Subject to the provisions of § 250.6...

  19. 31 CFR 1021.315 - Exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ENFORCEMENT NETWORK, DEPARTMENT OF THE TREASURY RULES FOR CASINOS AND CARD CLUBS Reports Required To Be Made By Casinos and Card Clubs § 1021.315 Exemptions. Refer to § 1010.315 of this chapter for exemptions...

  20. 31 CFR 1021.315 - Exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ENFORCEMENT NETWORK, DEPARTMENT OF THE TREASURY RULES FOR CASINOS AND CARD CLUBS Reports Required To Be Made By Casinos and Card Clubs § 1021.315 Exemptions. Refer to § 1010.315 of this chapter for exemptions...