NTP TECHNICAL REPORT ON THE TOXICOLOGY AND CARCINOGENESIS STUDIES OF VANADIUM PENTOXIDE (CAS NO. 1314-62-1) IN F344/N RATS AND B6C3F1 MICE (INHALATION STUDIES) NATIONAL TOXICOLOGY PROGRAM P.O. Box 12233 Research Triangle Park, NC 27709 December 2002 NTP TR 507 NIH Publication No. 03-4441 U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health Service National Institutes of Health FOREWORD The National Toxicology Program (NTP) is made up of four charter agencies of the U.S. Department of Health and Human Services (DHHS): the National Cancer Institute (NCI), National Institutes of Health; the National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health; the National Center for Toxicological Research (NCTR), Food and Drug Administration; and the National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention. In July 1981, the Carcinogenesis Bioassay Testing Program, NCI, was transferred to the NIEHS. The NTP coordinates the relevant programs, staff, and resources from these Public Health Service agencies relating to basic and applied research and to biological assay development and validation. The NTP develops, evaluates, and disseminates scientific information about potentially toxic and hazardous chemicals. This knowledge is used for protecting the health of the American people and for the primary prevention of disease. The studies described in this Technical Report were performed under the direction of the NIEHS and were conducted in compliance with NTP laboratory health and safety requirements and must meet or exceed all applicable federal, state, and local health and safety regulations. Animal care and use were in accordance with the Public Health Service Policy on Humane Care and Use of Animals. The prechronic and chronic studies were conducted in compliance with Food and Drug Administration (FDA) Good Laboratory Practice Regulations, and all aspects of the chronic studies were subjected to retrospective quality assurance audits before being presented for public review. These studies are designed and conducted to characterize and evaluate the toxicologic potential, including carcinogenic activity, of selected chemicals in laboratory animals (usually two species, rats and mice). Chemicals selected for NTP toxicology and carcinogenesis studies are chosen primarily on the bases of human exposure, level of production, and chemical structure. The interpretive conclusions presented in this Technical Report are based only on the results of these NTP studies. Extrapolation of these results to other species and quantitative risk analyses for humans require wider analyses beyond the purview of these studies. Selection per se is not an indicator of a chemical’s carcinogenic potential. Details about ongoing and completed NTP studies are available at the NTP’s World Wide Web site: http://ntp-server.niehs.nih.gov. Abstracts of all NTP Technical Reports and full versions of the most recent reports and other publications are available from the NIEHS’ Environmental Health Perspectives (EHP) http://ehp.niehs.nih.gov (800-315-3010 or 919-541-3841). In addition, printed copies of these reports are available from EHP as supplies last. A listing of all the NTP Technical Reports printed since 1982 appears on the inside back cover. NTP TECHNICAL REPORT ON THE TOXICOLOGY AND CARCINOGENESIS STUDIES OF VANADIUM PENTOXIDE (CAS NO. 1314-62-1) IN F344/N RATS AND B6C3F1 MICE (INHALATION STUDIES) NATIONAL TOXICOLOGY PROGRAM P.O. Box 12233 Research Triangle Park, NC 27709 December 2002 NTP TR 507 NIH Publication No. 03-4441 U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health Service National Institutes of Health 2 CONTRIBUTORS National Toxicology Program NTP Pathology Working Group Evaluated and interpreted results and reported findings Evaluated slides and prepared pathology report on rats (July 27, 2000) N.B. Ress, Ph.D., Study Scientist M.T. Butt, D.V.M., Chairperson J.H. Roycroft, Ph.D., Study Scientist Pathology Associates International D.W. Bristol, Ph.D. A.E. Brix, D.V.M., Ph.D. J.R. Bucher, Ph.D. Experimental Pathology Laboratories, Inc. J.R. Hailey, D.V.M. D. Dungworth, D.V.M. J.K. Haseman, Ph.D. University of California, Davis R.A. Herbert, D.V.M., Ph.D. J. Everitt, D.V.M. R.R. Maronpot, D.V.M. Chemical Industry Institute of Toxicology D.P. Orzech, M.S. G.P. Flake, M.D. S.D. Peddada, Ph.D. National Toxicology Program J.R. Hailey, D.V.M. G.N. Rao, D.V.M., Ph.D. National Toxicology Program C.S. Smith, Ph.D. R.A. Herbert, D.V.M., Ph.D. G.S. Travlos, D.V.M. National Toxicology Program K.L. Witt, M.S., ILS, Inc. M.P. Jokinen, D.V.M. Pathology Associates International IITRI R.R. Maronpot, D.V.M. Conducted 16-day and 3-month studies National Toxicology Program and evaluated pathology findings K. Nikula, D.V.M., Ph.D. Monsanto C. Aranyi, M.S., Principal Investigator A. Nyska, D.V.M. D.T. Kirkpatrick, Ph.D. National Toxicology Program R.E. Long, D.V.M. R.A. Renne, D.V.M. N. Rajendran, Ph.D. Battelle Toxicology Northwest A. Snelson, Ph.D. Evaluated slides and prepared pathology report on mice M.J. Tomlinson, D.V.M., Ph.D. (August 21, 2000) S.C. Vana, B.S. M.P. Jokinen, D.V.M., Chairperson Pathology Associates International Battelle Toxicology Northwest D. Dixon, D.V.M., Ph.D. Conducted 16-day special studies and 2-year studies National Toxicology Program and evaluated pathology findings J. Everitt, D.V.M. Chemical Industry Institute of Toxicology B.J. Chou, D.V.M., Ph.D., Principal Investigator G.P. Flake, M.D. J.A. Dill, Ph.D., Principal Investigator National Toxicology Program M.L. Clark, M.S.E. J.R. Hailey, D.V.M. S.R. Baum, B.S. National Toxicology Program K.M. Lee, Ph.D. R.A. Herbert, D.V.M., Ph.D. R.A. Miller, D.V.M., Ph.D. National Toxicology Program E.W. Morgan, M.S.E. M. Jayo, D.V.M., Ph.D., Observer R.A. Renne, D.V.M. Pathology Associates International R.A. Miller, D.V.M., Ph.D. Battelle Toxicology Northwest Experimental Pathology Laboratories, Inc. A. Nyska, D.V.M. Provided pathology quality assurance National Toxicology Program K. Ozaki, D.V.M., Ph.D., Observer J.F. Hardisty, D.V.M., Principal Investigator National Toxicology Program A.E. Brix, D.V.M., Ph.D. J.C. Seely, D.V.M. J.C. Seely, D.V.M. Experimental Pathology Laboratories, Inc. Vanadium Pentoxide, NTP TR 507 3 Dynamac Corporation Biotechnical Services, Inc. Prepared quality assurance audits Prepared Technical Report S. Brecher, Ph.D., Principal Investigator S.R. Gunnels, M.A., Principal Investigator L.M. Harper, B.S. Analytical Sciences, Inc. D.C. Serbus, Ph.D. Provided statistical analyses B.F. Hall, M.S. R.A. Willis, B.A., B.S. P.W. Crockett, Ph.D., Principal Investigator P.A. Yount, B.S. L.J. Betz, M.S. M.R. Easterling, Ph.D. K.P. McGowan, M.B.A. J.T. Scott, M.S. 4 CONTENTS ABSTRACT . 7 EXPLANATION OF LEVELS OF EVIDENCE OF CARCINOGENIC ACTIVITY . 12 TECHNICAL REPORTS REVIEW SUBCOMMITTEE . 13 SUMMARY OF TECHNICAL REPORTS REVIEW SUBCOMMITTEE COMMENTS . 14 INTRODUCTION . 17 MATERIALS AND METHODS . 27 RESULTS . 45 DISCUSSION AND CONCLUSIONS . 93 REFERENCES . 99 APPENDIX A Summary of Lesions in Male Rats in the 2-Year Inhalation Study of Vanadium Pentoxide . 109 APPENDIX B Summary of Lesions in Female Rats in the 2-Year Inhalation Study of Vanadium Pentoxide . 149 APPENDIX C Summary of Lesions in Male Mice in the 2-Year Inhalation Study of Vanadium Pentoxide . 185 APPENDIX D Summary of Lesions in Female Mice in the 2-Year Inhalation Study of Vanadium Pentoxide . 225 APPENDIX E Genetic Toxicology . 263 APPENDIX F Cardiopulmonary Physiology Studies . 269 APPENDIX G Clinical Pathology Results . 275 APPENDIX H Organ Weights and Organ-Weight-to-Body-Weight Ratios . 283 APPENDIX I Reproductive Tissue Evaluations and Estrous Cycle Characterization . 289 APPENDIX J Immunotoxicology Studies . 293 APPENDIX K Tissue Burden Results . 299 APPENDIX L Chemical Characterization and Generation of Chamber Concentrations . 313 Vanadium Pentoxide, NTP TR 507 5 APPENDIX M Ingredients, Nutrient Composition, and Contaminant Levels in NTP-2000 Rat and Mouse Ration . 329 APPENDIX N Sentinel Animal Program . 333 APPENDIX O Molecular Oncology Studies . 337 6 Vanadium Pentoxide, NTP TR 507 SUMMARY Background Vanadium pentoxide is used in the production of vanadium and steel alloys and is emitted by burning fossil fuels. Exposure to vanadium pentoxide occurs during the cleaning of oil-fired boilers and furnaces. Methods We exposed groups of 50 male and 50 female rats to atmospheres containing aerosols of 0.5, 1, or 2 mg of vanadium pentoxide particles per cubic meter of air. We also exposed groups of 50 male and 50 female mice to atmospheres containing 1, 2, or 4 mg vanadium pentoxide per cubic meter. Animals were exposed six hours per day, five days per week for two years. Tissues from more than 40 sites on each animal were examined. Results Male rats exposed to vanadium pentoxide had greater than normal incidences of lung neoplasms, and some lung tumors also occurred in exposed female rats. Other lesions including inflammation, fibrosis, and hyperplasia also occurred in the respiratory tract (nose, larynx, and lung) of male and female rats. These lesions were more severe at higher vanadium pentoxide concentrations. Male and female mice had even greater incidences of alveolar/bronchiolar neoplasms of the lung, and many of the male mice in the highest exposure group died before the end of the study. Lesions including epithelial hyperplasia, inflammation, fibrosis, and squamous metaplasia occurred in the respiratory tract (nose, larynx, and lung) of male and female mice. Conclusions We conclude that exposure to vanadium pentoxide particles caused lung neoplasms in male rats and possibly in female rats, and in male and female mice.