John Sivey, Towson University – Safeners in Herbicides

The use of herbicides is widespread, but we don’t know the whole story.

John Sivey, assistant professor of chemistry at Towson University, is looking into what happens to these chemicals after they are applied.

John Sivey (Sĭ’-vee) is the Jess and Mildred Fisher Endowed Professor of Chemistry at Towson University. Professor Sivey’s research group investigates the transformation mechanisms and fate of active and “inert” constituents of agrochemical formulations. His team also examines the chemistry and consequences of often-overlooked halogenating agents (e.g., Cl₂O, BrCl, and BrOCl) in drinking water. Professor Sivey teaches courses in analytical and environmental chemistry, including an Honors College seminar entitled The Polluted States of America.
Professor Sivey received his PhD in Environmental Engineering and Chemistry from the Johns Hopkins University, his MS in Environmental Engineering and Science from Clemson University, and his BS in Chemistry from Central Michigan University. Prior to joining the faculty of the Department of Chemistry at Towson University, Professor Sivey completed postdoctoral work in the Department of Chemical and Environmental Engineering at Yale University.

Safeners in Herbicides

Runoff of herbicides into rivers and lakes can compromise the health of these ecosystems and limit their use as sources of drinking water. For several decades, scientists have been studying the environmental behavior of herbicides, which are classified as “active” ingredients in agrochemical products. These mixtures also typically include several “inert” ingredients.  As a society, we have largely overlooked the possible adverse effects of these inert ingredients. From an environmental safety perspective, this research gap is surprising because some inert ingredients are chemically quite similar to herbicide active ingredients. Indeed, despite their name, some “inert” ingredients are known to be biologically-active, particularly toward plants.

One such class of “inert” agrochemicals is called safeners. Most herbicides have the potential to damage crops in addition to killing weeds. Safeners serve as a “chemical inoculation” that protects crops, but not weeds, from herbicide-induced injury. Safeners are used around the world to protect important crops such as corn, wheat, and rice. Despite their widespread use, surprisingly few previous studies have examined the environmental behavior of safeners. My research team and our collaborators are working to better understand what happens to safeners after they are applied to farm fields.

We have discovered that some safeners can transform under environmentally-relevant conditions into substances that are likely to pose greater risks to the environment compared to the original compound.  In one instance, an inert safener can react with components of soil to form an “active” ingredient .  Conventional wisdom in environmental science assumes that as agrochemicals break down in the environment, the products will be less hazardous than the starting material.  Our results challenge this conventional wisdom and suggest that regulators may need to reconsider how the risks associated with so-called “inert” agrochemicals are assessed. 

Read More:
Additional information on safeners
Prof. Sivey’s research group