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Nigel J. Walker, Ph.D., D.A.B.T.

National Toxicology Program Division - Associate Director's Office

Nigel J. Walker, Ph.D., D.A.B.T.
Nigel J. Walker, Ph.D.
Deputy Division Director for Science
Tel (919) 541-4893
Fax (301) 451-5596
P.O. Box 12233
Mail Drop K2-02
Research Triangle Park, NC 27709

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Nigel Walker, Ph.D., D.A.B.T., is the Deputy Director for Science for the Division of the National Toxicology Program (NTP) at the National Institute of Environmental Health Sciences (NIEHS), one of National Institutes of Health. In this capacity he works with the Division Director in the formulation, coordination and implementation of activities necessary to carry out the scientific missions of the National Toxicology Program.


Walker is also an adjunct toxicologist in the Toxicology Branch responsible for designing studies to evaluate the toxicity and carcinogenicity of chemicals selected by the National Toxicology Program. He is the lead scientist for the NTP Nanotechnology Safety Initiative that is evaluating the safety of engineered nanoscale materials.


Walker also serves as the NIEHS project officer coordinating an Interagency Agreement (Y1-ES-1027) with the National Center for Toxicological Research/FDA that supports NTP hazard assessment activities evaluating potential adverse effects caused by exposure to chemical and physical agents.


Walker received his B.Sc. in biochemistry in England from the University of Bath in 1987 and his Ph.D. in biochemistry from the University of Liverpool in 1993. Following postdoctoral training in environmental toxicology at the Johns Hopkins School of Hygiene and Public Health in Baltimore Md., he moved to the NIEHS, where he has been since 1995.


His research interests are environmental toxicology, quantitative dose response modeling and risk assessment, mixtures toxicology and nanotoxicology. He has published over 90 peer-reviewed publications and reports and two of his publications received Best Paper awards by the by the Risk Assessment Specialty Section of the Society of Toxicology.


He currently serves on the editorial board for Toxicology and Applied Pharmacology. He is an adjunct associate professor in the Curriculum of Toxicology at the University of North Carolina at Chapel Hill, was President of the North Carolina Society of Toxicology in 2005, and is a board-certified toxicologist.


Selected Publications

  1. Rider CV, Carlin DJ, DeVito MJ, Thompson CL, Walker NJ. Mixtures research at NIEHS: an evolving program. Toxicology 2013 313(2-3):94-102. [Abstract]
  2. Schug,TT , Johnson, AN, Balshaw DM, Garantziotis S, Walker NJ, Weis C, Nadadur, SS, Birnbaum, LS (2013) ONE Nano: NIEHS's strategic initiative on the health and safety effects of engineered nanomaterials. Environmental health perspectives 121(4):410-414. [Abstract]
  3. Hooth MJ, Nyska A, Fomby LM, Vasconcelos DY, Vallant M, Devito MJ, Walker NJ. (2012) Repeated dose toxicity and relative potency of 1,2,3,4,6,7-hexachloronaphthalene (PCN 66) 1,2,3,5,6,7-hexachloronaphthalene (PCN 67)compared to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for induction of CYP1A1, CYP1A2 and thymic atrophy in female Harlan Sprague-Dawley rats. Toxicology 301, 85-93. [Abstract]
  4. Hussain S, Al-Nsour F, Rice AB, Marshburn J, Yingling B, Ji Z, Zink JI, Walker NJ, Garantziotis S. (2012) Cerium dioxide nanoparticles induce apoptosis and autophagy in human peripheral blood monocytes. ACS Nano. 6,5820-9. [Abstract]
  5. Satoh M, Chan EK, Ho LA, Rose KM, Parks CG, Cohn RD, Jusko TA, Walker NJ, Germolec DR, Whitt IZ, Crockett PW, Pauley BA, Chan JY, Ross SJ, Birnbaum LS, Zeldin DC, Miller FW. (2012) Prevalence and sociodemographic correlates of antinuclear antibodies in the United States. Arthritis Rheum. 64, 2319-27. [Abstract]
  6. Pandiri, A.R., Sills, R.C., Hoenerhoff, M.J., Peddada, S.D., Ton, T.T., Hong, H.L., Flake, G.P., Malarkey, D.E., Olsen, G.R., Pogribny, I.P, Walker, N.J., and Boudreau, M.D. (2011) Aloe vera nondecolorized Whole Leaf Extract-Induced Large Intestinal Tumors in F344 Rats Share Similar Molecular Pathways with Human Sporadic Colorectal Tumors. Toxicol Pathol, 39, 1065-1074. [Abstract]
  7. Abdel-Rahman, A., Anyangwe, N., Carlacci, L., Casper, S., Danam, R.P., Enongene, E., Erives, G., Fabricant, D.,  Gudi, R., Hilmas C.J., Hines, F., Howard, P., Levy, D., Lin, Y., Pfeiler, E., Thurmond, T.S., Turujman, S, and Walker, N.J. (2011) The Safety and Regulation of Natural Products Used as Foods and Food Ingredients. Toxicol. Sci. 123, 333-348. [Abstract]
  8. Yoshizawa, K., Walker, N.J., Nyska, A., Kissling, G.E., Jokinen, M.P., Brix, A.E., Sells, D.M., Wyde, M.E. (2010) Thyroid follicular lesions induced by oral treatment for two years with 2,3,7,8-tetrachlorodibenzo-p-dioxin and dioxin-like compounds in female Harlan Sprague-Dawley rats. Toxicologic pathology 38(7):1037-1050. [Abstract]
  9. Auerbach, S.S., Shah, R.R., Mav, D., Smith, C.S., Walker, N.J., Vallant, M.K., Boorman, G.A., and Irwin, R.D. (2010) Predicting the hepatocarcinogenic potential of alkenylbenzene flavoring agents using toxicogenomics and machine learning. Toxicol Appl. Pharmacol 243, 300-14. [Abstract]
  10. Gopee, N.V., Roberts, D.W., Webb, P., Cozart, C.R., Siitonen, P.H., and Latendresse, J.R., Warbritton, A.R., Yu, W.W., and Colvin, V.L., Walker, N.J., Howard, P.C. (2009) Quantitative determination of skin penetration of PEG-coated CdSe quantum dots in dermabraded but not intact SKH-1 hairless mouse skin. Toxicol Sci. 111, 37-48. [Abstract]
  11. Walker, N.J., and Bucher, J.R. (2009) A 21st century paradigm for evaluating the health hazards of nanoscale materials? Toxicol Sci. 110, 251-4. [Abstract]
  12. Small is Different: A Science Perspective on the Regulatory Challenges of Nanoscale Report of the Expert Panel on Nanotechnology (2008) [The Council of Canadian Academies]
  13. Jeong, Y.C., Walker, N.J., Burgin, D.E., Kissling, G., Gupta, M., Kupper, L., Birnbaum, L.S., and Swenberg, J.A. (2008) Accumulation of M(1)dG DNA adducts after chronic exposure to PCBs, but not from acute exposure to polychlorinated aromatic hydrocarbons. Free Radic Biol Med. 45, 585-91. [Abstract]
  14. Walker, N.J., Wyde, M.E., Fischer, L.J., Nyska, A., and Bucher, J.R. (2006) Comparison of chronic toxicity and carcinogenicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in two-year bioassays in female Sprague-Dawley rats. Mol. Nutr. Food Res. 50, 934-944. [Abstract]
  15. Maynard, A.D, Aitken, R.J., Butz, T., Colvin, V., Donaldson, K., Oberdorster, G., Philbert, M.A., Ryan, J., Seaton, A., Stone, V., Tinkle, S.S., Tran, L., Walker, N.J., and Warheit, D.B. (2006). Safe handling of nanotechnology, Nature 444, 267-269.
  16. van den Berg, M., Birnbaum, L., Denison, M., De Vito, M., Farland, W., Feeley, M., Fiedler, H., Hakansson, H., Hanberg, A., Haws, L., Rose, M., Safe, S., Schrenk, D., Tohyama, C., Tritscher, A., Tuomisto, J., Tysklind, M., Walker, N.J., and Peterson, R.E. (2006) The 2005 World Health Organization re-evaluation of human and mammalian toxic equivalency factors for dioxins and dioxin-like compounds. Toxicol Sci. 93, 223-241 [Abstract]
  17. Walker, N.J., Crockett, P., Nyska, A., Brix, A., Jokinen, M.P., Sells, D.M., Hailey, J.R., Easterling, M., Haseman, J.K., Yin, M., Wyde, M.E., Bucher, J.R., and Portier, C.J. (2005) Dose-additive carcinogenicity of a defined mixture of "dioxin - like compounds." Environ Health Perspect 113, 43-48. [Abstract]
  18. Hailey, J.R., Walker, N.J., Sells, D.M., Brix, A.E., Jokinen, M.P., and Nyska, A. (2005) Classification of proliferative hepatocellular lesions in Harlan Sprague Dawley rats chronically exposed to dioxin-like compounds. Toxicol Pathol 33,165-174. [Abstract]



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