Allison MacKay, Professor & Chair
Department of Civil, Envrionemntal & Geodetic Engineering
The Ohio Statue University

Structure Matters!  Understanding the outsized role of organic matter in contaminant fate

Abstract: This presentation highlights outcomes from the creative inquiry of student advisees who each posed the question, “What is it about the structure of organic matter that is causing contaminants to degrade – or  to sorb in unexpected ways?” Insights were discovered by applying tools to probe organic matter at the molecular level.  Femtosecond laser flash photolysis was used to characterize the abundance of specific functional groups in organic matter that are can produce intermediate reactants for the photochemical degradation of contaminants in aquatic system.  These observations helped to explain why, despite the higher apparent reactivity of microbially-sourced organic matter in treated wastewater effluent, reactivity was attenuated upon mixing with naturally-occurring riverine organic matter.  High resolution mass spectrometry showed the shifts in chemical formulae of organic matter components, following sequential drinking water treatment processes.  These observations were used to explain variability in harmful byproducts formed in the chlorine disinfection of drinking water.  Finally, atomistic computational chemistry tools were used to visualize and quantify organic contaminant interaction energies with soil organic matter.  Results help to describe why organic matter shows unexpectedly high sorption of organic compounds with positive charge.  Collectively, these findings advance understanding of the role of organic matter in contaminant fate that have not been captured using bulk descriptors of these heterogeneous materials present in all aquatic systems.
 

Bio: Dr. Allison MacKay is Professor and Chair of Civil, Environmental and Geodetic Engineering. She is leading the department at a time of strong student enrollments, recent faculty growth and rapidly changing civil infrastructure needs and innovations. Her research program is directed toward the fate of contaminants in engineered and natural aquatic systems. Current project examples include developing better guidance for drinking water plant operators to manage the treatment of toxins from algae in reservoirs, and integrating advanced molecular computation tools to identify the binding mechanisms of contaminants in sediments and soils. Her teaching interests include chemical treatment processes and environmental sustainability. She currently serves on the Department Heads Coordinating Council of the American Society of Civil Engineers. She is President‐Elect of the Association of Environmental Engineering and Science Professors where she was instrumental in creating a national forum within this organization for environmental engineering program leaders. Dr. MacKay holds Doctoral and Master degrees in Environmental Engineering from Massachusetts Institute of Technology. She received a Bachelor of Applied Science degree in Engineering Science (Chemical Option) from the University of Toronto.

Allison MacKay, Professor & Chair
Department of Civil, Envrionemntal & Geodetic Engineering
The Ohio Statue University

Structure Matters!  Understanding the outsized role of organic matter in contaminant fate

Abstract: This presentation highlights outcomes from the creative inquiry of student advisees who each posed the question, “What is it about the structure of organic matter that is causing contaminants to degrade – or  to sorb in unexpected ways?” Insights were discovered by applying tools to probe organic matter at the molecular level.  Femtosecond laser flash photolysis was used to characterize the abundance of specific functional groups in organic matter that are can produce intermediate reactants for the photochemical degradation of contaminants in aquatic system.  These observations helped to explain why, despite the higher apparent reactivity of microbially-sourced organic matter in treated wastewater effluent, reactivity was attenuated upon mixing with naturally-occurring riverine organic matter.  High resolution mass spectrometry showed the shifts in chemical formulae of organic matter components, following sequential drinking water treatment processes.  These observations were used to explain variability in harmful byproducts formed in the chlorine disinfection of drinking water.  Finally, atomistic computational chemistry tools were used to visualize and quantify organic contaminant interaction energies with soil organic matter.  Results help to describe why organic matter shows unexpectedly high sorption of organic compounds with positive charge.  Collectively, these findings advance understanding of the role of organic matter in contaminant fate that have not been captured using bulk descriptors of these heterogeneous materials present in all aquatic systems.
 

Bio: Dr. Allison MacKay is Professor and Chair of Civil, Environmental and Geodetic Engineering. She is leading the department at a time of strong student enrollments, recent faculty growth and rapidly changing civil infrastructure needs and innovations. Her research program is directed toward the fate of contaminants in engineered and natural aquatic systems. Current project examples include developing better guidance for drinking water plant operators to manage the treatment of toxins from algae in reservoirs, and integrating advanced molecular computation tools to identify the binding mechanisms of contaminants in sediments and soils. Her teaching interests include chemical treatment processes and environmental sustainability. She currently serves on the Department Heads Coordinating Council of the American Society of Civil Engineers. She is President‐Elect of the Association of Environmental Engineering and Science Professors where she was instrumental in creating a national forum within this organization for environmental engineering program leaders. Dr. MacKay holds Doctoral and Master degrees in Environmental Engineering from Massachusetts Institute of Technology. She received a Bachelor of Applied Science degree in Engineering Science (Chemical Option) from the University of Toronto.