Chemical Mixtures Environmental Health Risk Assessment Methods: In Memory of Dr. Jane Ellen Simmons and Jeff Swartout
Sunday, December 4, 2022 with Linda K. Teuschler and Glenn E. Rice (8:30AM-5:30PM)
This full-day workshop focuses on current and emerging methods and data for assessing health risks posed by exposures to chemical mixtures in the environment and is dedicated to the memory of two of our beloved colleagues who pioneered work on mixtures, Dr. Jane Ellen Simmons and Jeff Swartout.
Key concepts and terminology are presented, and both whole mixture and component-based methods are discussed. Response addition and dose addition are described and include the following methods: Finney vs. Berenbaum definitions of additivity, the hazard index (HI), interaction-based HI, relative potency factors, toxicity equivalence factors, integrated addition, and detection of departures from dose addition. Whole mixture methods consist of the derivation of toxicity values for whole mixtures, sufficient similarity and mixture fractions. Future directions are discussed, including the use of data from new alternative methods (NAM) to inform chemical mixture risk assessment methods, the interface between toxicology study design and mixture risk assessment methods, biologically-based models of toxicokinetics and toxicodynamics of mixtures and applying physiologically-based pharmacokinetic modeling of mixtures along with other methods to evaluate combination therapy.
The risk assessment examples developed in the workshop are adapted from real-world mixture analyses, e.g., waste site contaminants, pesticide applications, botanical ingredients and drinking water disinfection by-product exposures. The “hands-on” exercise demonstrating the methods is an essential part of this workshop. Discussions include real world examples, exercise results, and answers to general questions. (We ask participants to bring a calculator or laptop).
The views expressed in this abstract are those of the authors and do not necessarily reflect the views or policies of the USEPA.