Professional Profile
Ms. Tammie Covington is a Supervising Scientist in ToxStrategies’ Health Sciences Practice. As an applied mathematician, she has over 30 years of experience in the development and application of physiologically based pharmacokinetics (PBPK) models, primarily in the areas of risk and exposure assessment. The models she has developed have been for occupational and environmental exposure for various species including human. They have also encompassed various life stages including pregnancy, lactation and entire lifetime, and have incorporated mathematical descriptions of physiological changes occurring during these life stages. Her expertise extends to applying sensitivity, Monte Carlo, and Markov chain Monte Carlo analyses to these models. Most recently, she has used PBPK modeling and NHANES biomarker data to determine the feasibility of this framework for assessing potentially increased risk due to allostatic loads in relation to the U.S. Environmental Protection Agency’s (EPA) environmental justice initiative. Her work has also included exploring the impact of genetic polymorphisms to better understand risk to susceptible populations through the use of PBPK modeling and Monte Carlo analysis. Additionally, she has repurposed existing models for new uses such as use with reverse dosimetry to estimate distributions of potential inhaled concentrations based on exhaled breath concentrations and determination of the feasibility of a proposed biomarker for asthma inhaler use. Ms. Covington has also applied PBPK models to the development of various regulatory risk levels and evaluated existing risk levels by using PBPK models and Markov chain Monte Carlo analysis to base risk assessments on internal dose rather than external exposure and thus, allow for better extrapolation between animal and human exposures and across routes of exposure.