Health Impacts & Exposure Science
Dr. Timchalk received a B. S. in Biology in 1978 from the State University of New York, and a Ph.D. in 1986 from the Department of Pharmacology and Toxicology, The Albany Medical College. He is currently certified as a Diplomat of the American Board of Toxicology. In 1986 he joined the Dow Chemical Company as a post-doctoral fellow and while at Dow he was a Research and Technical Leader within the Pharmacokinetics and Metabolism group prior to accepting his current position. In 1997 he joined PNNL as a Staff Scientist. In this position he is continuing to pursue his interest in human health research. Dr. Timchalk is currently the principal investigator or co-investigator on several DHHS/NIH grants and DoD Cooperative Biological Engagement Program. His research has been published in over 90 peer reviewed manuscripts, and has resulted in numerous patents and book chapters. He has likewise provided support on technical review and numerous advisory committees. He has held a number of leadership positions (including President) within the Society of Toxicology, Biological Modeling Specialty Section. Over the course of his career Dr. Timchalk has been acknowledged both for his professional accomplishments and for his ongoing interest in supporting the development of young scientists. His research has been recognized by awards from the Environmental Business Journal (Technical Merit award, 2001), and R&D 100 Nomination (2004). In addition, he received the Department of Energy, Office of Science Outstanding Mentor Award recipient (2002); and the Pacific Northwest National Laboratory, Chester I. Cooper Mentor of the Year Award (2003).
- Global health: providing training to scientist within low- & middle-income countries on programmatic grant development to achieve sustainability in a global research environment.
- Development of multidisciplinary integrated research programs and teams to advance exposure assessment and toxicology through the development and implementation of novel technologies.
- Diagnostic non-invasive biological monitoring (development/validation of sensors).
- Development of physiologically based pharmacokinetic and pharmacodynamic model for single agents and mixtures.
- Life-stage specific sensitivities to toxic agents: modeling early development.
Education and Credentials
- 1982 - 1986 Doctor of Philosophy (Ph.D.) The Albany Medical College of Union University, Department of Pharmacology & Toxicology, Albany, NY 12208 Emphasis: Toxicology/ Pharmacology
- 1974 - 1978 Bachelor of Science (B. S.) State University of New York at Oneonta, Oneonta, NY, 13820. Major: Biology Minor: Chemistry
- Diplomat of the American Board of Toxicology, DABT (1994 - present) Re-certified (2000-2004; 2005-2009; 2010-2014)
Affiliations and Professional Service
- Society of Toxicology- Full Member (1987- present)
- Society of Toxicology- Biological Modeling Specialty Section (2000-present)
- Society of Toxicology- Mixtures Specialty Section (2010-present)
- Society of Toxicology- Councilor, Biological Modeling Specialty Section (2002-2004)
- Society of Toxicology- Vice President-Elect, Biological Modeling Specialty Section (2004)
- Society of Toxicology- Vice President, Biological Modeling Specialty Section (2005)
- Society of Toxicology- President, Biological Modeling Specialty Section (2006)
- Society of Toxicology- Past President, Biological Modeling Specialty Section (2007)
- Sigma Xi, Scientific Research Society- Full Member (1986 - 2008)
- International Society for the Study of Xenobiotics (1995 - present)
- Pacific Northwest Society of Toxicology (1999- present)
- Michigan Society of Toxicology (1995 - 1997)
Awards and Recognitions
- Albany Medical College Trustees Scholarship (1982 - 1986)
- National Research Service Award, NIEHS 5T32 ES07058-05 (1982 - 1983)
- Albany Medical College Teaching Assistantship (1983 - 1986)
- Albany Medical College Student Travel Program Grant (1985)
- Society of Toxicology, Student Travel Award (1985 - 1986)
- Society of Toxicology, Risk Assessment Specialty Section Best Paper Award (1999)
- Environmental Business Journal Technical Merit Award â€" Saliva Biomonitor (2001)
- Department of Energy, Office of Science Outstanding Mentor Award recipient (2002)
- Pacific Northwest National Laboratory, Chester I. Cooper Mentor of the Year Award (2003)
- R&D 100 Nomination, Pacific Northwest National Laboratory â€" Saliva Biomonitoring Technology (2004)
- Environmental Business Journal Technical Merit Award â€" Insecticide Biosensor (2006)
- Society of Toxicology, Biological Modeling Specialty Section- Best Paper Award (2011) - Hinderliter et al Reg. Tox. and Pharm., 61(1): 82-92, PMID: 21722690.
- Society of Toxicology, Biological Modeling Specialty Section- Best Paper Award (2012) â€" Corley et al Toxicol. Sci. 128(2): 500-516, PMID: 22584687
- Kousba AA, TS Poet, and C Timchalk. 2007. "AGE-RELATED BRAIN CHOLINESTERASE INHIBITION KINETICS FOLLOWING IN VITRO INCUBATION WITH CHLORPYRIFOS-OXON AND DIAZINON-OXON." Toxicological Sciences 95(1):147-155. doi:doi:10.1093/toxsci/kfl123
- Marty MS, JY Domoradzki, SC Hansen, C Timchalk, MJ Bartels, and JL Mattsson. 2007. "The Effect of Route, Vehicle, and Divided Doses on the Pharmacokinetics of Chlorpyrifos and its Metabolite Trichloropyridinol in Neonatal Sprague-Dawley Rats." Toxicological Sciences 100(2):360-373. doi:10.1093/toxsci/kfm239
- Timchalk C, AL Busby, JA Campbell, LL Needham, and D Barr. 2007. "Comparative Pharmacokinetics of the Organophosphorus Insecticide Chlorpyrifos and its Major Metabolites Diethylphosphate, Diethylthiophosphate and 3,5,6-Trichloro-2-pyridinol in the Rat." Toxicology 237(1-3):145-157. doi:10.1016/j.tox.2007.05.007
- Timchalk C, AA Kousba, and TS Poet. 2007. "An Age-Dependent Physiologically-Based Pharmacokinetic/Pharmacodynamic Model for the Organophosphorus Insecticide Chlorpyrifos in the Preweanling Rat." Toxicological Sciences 98(2):348-365. doi:10.1093/toxsci/kfm119
- Poet TS, and C Timchalk. 2006. Proposed Occupational Exposure Limits for Non-Carcinogenic Hanford Waste Tank Vapor Chemicals. PNNL-15736, Pacific Northwest National Laboratory, Richland, WA.
- Barton HA, TP Pastoor, K Baetcke, JE Chambers, J Diliberto, NG Doerrer, JH Driver, CE Hastings, S Iyengar, R Krieger, B Stahl, and C Timchalk. 2006. "The Acquisition and Application of Absorption, Distribution, Metabolism, and Excretion (ADME) Data in Agricultural Chemical Safety Assessments." Critical Reviews in Toxicology 36(1):9-35.
- Timchalk C, TS Poet, and AA Kousba. 2006. "Age-dependent pharmacokinetic and pharmacodynamic response in preweanling rats following oral exposure to the organophosphorus insecticide chlorpyrifos ." Toxicology 220(1):13-25. doi:10.1016/j.tox.2005.11.011
- Campbell JA, C Timchalk, AA Kousba, H Wu, BR Valenzuela, and EW Hoppe. 2005. "Negative Ion Chemical Ionization Mass Spectrometry for the Analysis of 3,5,6-trichloro-2-pyridinol in Saliva of Rats Exposed to Chlorpyrifos." Analytical Letters 38(6):939-949.
- Cole TB, BJ Walter, DM Shih, AD Tward, AJ Lusis, C Timchalk, RJ Richter, LG Costa, and CE Furlong. 2005. "Toxicity of chlorpyrifos and chlorpyrifos oxon in a transgenic mouse model of the human paraoxonase (PON1) Q192R polymorphism." Pharmacogenetics and Genomics 58(8):589-598.
- Furlong CE, TB Cole, BJ Walter, DM Shih, A Tward, AJ Lusis, C Timchalk, RJ Richter, and LG Costa. 2005. "Paraoxonase 1 (PON1) Status and Risk of Insecticide Exposure." Journal of Biochemical and Molecular Toxicology 19(3):182-183. doi:10.1002/jbt.20079
- Slikker W, JF Young, RA Corley, DC Dorman, RB Conolly, T Knudsen, BL Erstad, RH Luecke, EM Faustman, C Timchalk, and DR Mattison. 2005. "Improving Predictive Modeling in Pediatric Drug Development: Pharmacokinetics, Pharmacodynamics, and Mechanistic Modeling." In NPA Workshop: PBPK/PD Models for Developing Humans: Risk Assessment Strategies and Research Recommendations. Published in Annals of the New York Academy of Science, vol. 1053, pp. 505-518. New York Academy of Sciences, New York. doi:10.1196/annals.1344.044
- Timchalk C, TS Poet, MN Hinman, AL Busby, and AA Kousba. 2005. "PHARMACOKINETIC AND PHARMACODYNAMIC INTERACTION FOR A BINARY MIXTURE OF CHLORPYRIFOS AND DIAZINON IN THE RAT." Toxicology and Applied Pharmacology 205(1):31-42.
- Poet TS, AA Kousba, SL Dennison, and C Timchalk. 2004. "Physiologically Based Pharmacokinetic/Pharmacodynamic Model for the Organophosphorus Pesticide Diazinon." NeuroToxicology 25(6):1013-1030. doi:10.1016/j.neuro.2004.03.002