Joint Chesapeake-Potomac Regional Chapter and 
Hudson-Delaware Chapter SETAC 2022 Spring Meeting

Keynote Speaker

CPRC and HDC SETAC have arranged for a keynote address on Monday April 11, 2022.  

Title : Second Generation Models of Environmental Partitioning and Toxicity: The End of the Age of Octanol

Keynote SpeakerDominic M. Di Toro

Abstract:  The first generation of predictive models of environmental partition coefficients (e.g. KOC) and toxicity concentrations (e.g. baseline narcosis LC50) relied on the octanol water partition coefficient (KOW) as the chemical property used in the prediction equation. These were initially developed for hydrophobic, non-polar compounds. The remarkable success of these models resulted in their application to wider classes of compounds. As data for an increasing number of compounds were examined, it became clear that specific equations for different classes of compounds were required, for example different equations of KOCs for non-polar and polar compounds, and chemical class corrections for toxicity models. However, it was not clear how to generalize these class specific models so that they would cover a much broader range of compounds, in particular compounds that may be more difficult to classify as belonging to a particular class.

The second generation of models replaced the compound’s chemical property -- the single octanol water partition coefficient -- with a series of five compound specific Abraham Parameters (APs). These five APs are used to model partitioning from water and air to many environmental phases important to fate and transport modeling. Bioconcentration and toxicity models for different modes of action have been developed that use the same APs . These models have been shown to be remarkably successful and broadly applicable for neutral organic molecules.

However, models using APs are not yet commonly used due to their unfamiliarity and until recently the unavailability of APs for many compounds of interest. The basis, compound properties, and availability of APs will be discussed. The presentation will be designed for environmental professionals as an introduction to the topic. A few published examples of their applications, and a brief discussion of their limitations, will conclude the presentation.

Biosketch: Dominic M. Di Toro is the Edward C. Davis Professor of Civil and Environmental Engineering at the University of Delaware. He was elected to the National Academy of Engineers in February, 2005. His other awards include the Institute of Scientific Information Highly Cited Researcher, 2003 and The Founders Award of the Society of Environmental Toxicology and Chemistry.

Dr. Di Toro has specialized in the development and application of mathematical and statistical models to stream, lake, estuarine and coastal water and sediment quality problems. He has published over one hundred technical papers, as well as Sediment Flux Modeling, published by J. Wiley & Sons. He has participated as Expert Consultant, Principal Investigator and Project Manager on numerous water quality studies for industry, research foundations and governmental agencies. Recently, his work has focused on the development of water and sediment quality criteria for the EPA, sediment flux models for nutrients and metals, and integrated hydrodynamic, sediment transport and water quality models.

Dr. Di Toro received his B.E.E. in electrical engineering with honors from Manhattan College in 1963, his M.A. in electrical engineering in 1965 and his Ph.D. in Civil and Geological Engineering in 1967, both from Princeton University. He joined the faculty of Manhattan College and became the Donald J. O’Connor Professor of Environmental Engineering in 1999. In 2003, he joined the faculty at the University of Delaware.

Dr. Di Toro also served as a Senior Research Consulting Engineer at Hydroscience, Inc. from 1969-1980 and was a founding partner of the successor firm HydroQual, Inc, a consulting firm that specializes in water quality modeling, where he was Principal Consultant from 1980 to 2004.

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