Chemistry researchers developed a computerized framework program to screen the environmental toxicity of pesticides and create safer alternatives in a study released late last month.
The team of researchers from the Columbian College of Arts and Sciences analyzed how pesticides degrade when exposed to light to create data that trains their new framework program to screen for unsafe characteristics in pesticides that need alteration. The researchers created a model framework blueprint that chemical manufacturers can use to design pesticides with characteristics that will better control degradation.
The study noted the failure to control the degradation of pesticides can have “devastating consequences” for humans and the environment.
More than 5.6 billion pounds of pesticides are used around the world annually, which accidentally poisons about 25 million agricultural workers each year. The United States drops more than one billion pounds of pesticides per year, the second most in the world behind China.
Jakub Kostal – the principal investigator that oversees the study, the co-director of the environmental and green chemistry master’s program and an assistant professor of chemistry – said the program offers a way for chemists to take charge of developing pesticides with safe chemicals. He said the typical process in which toxicologists determine the safety of a pesticide happens after the pesticide is fully developed and commercialized, the program offers a way for chemists to “get ahead” of releasing potentially dangerous chemicals.
Unintended exposure to pesticides can occur through contaminated drinking water, most commonly found in groundwater, spray drift, workers in the pesticide industry and exterminators of house pests.
“We want pesticides to not persist in the environment,” Kostal said. “We want them to be effective, but then to degrade into something benign.”
He said the team of researchers included both undergraduate and graduate students who performed most of the computational research under his direction. Kostal said the students used predictive modeling – a statistical technique to predict future behavior – to characterize aspects of the pesticide like degradation, toxicity and performance that notify chemists about what molecules need to be added or removed to make the chemicals safer to humans and the environment.
He said the study provides a blueprint that applies to other sectors like cosmetics and cleaners. Kostal said regulatory agencies like the Environmental Protection Agency can use the screening method to suggest safety changes for certain chemicals.
“What we’re after is not finding out that pesticides might be toxic or that some of them are not degradable but figuring out what changes we could make to these structures, these molecules to change their properties,” Kostal said.
Kostal said the study aims to advocate for designing chemicals not solely based on the economics and performance of a pesticide but also its environmental safety, toxicity and persistence. He said GW is constrained to using the market’s available pesticides, and the study provides the tools for manufacturers to create safer chemicals.
“GW has some sustainable initiatives, but they need to put way more weight behind some of these initiatives,” Kostal said. “It’s kind of having a vision of what’s going to be needed in the marketplace, years from now, not what maybe the market demands right now.”
Jessica Lewer, the primary researcher of the study and a recent graduate, said the research is a “step approach” for people to begin to think about redesigning chemicals in pesticides with environmental, safety and public health goals in mind.
“Pesticides are obviously a hot topic in the environment as they’re building up in the environment,” Lewer said. “And then obviously, those toxic traits that they’re having can cause negative impacts to human lives in the environment.”
She said the team of researchers first looked at the “route” of degradation of pesticides in the environment due to sunlight and then trained their model to copy match the data found in the research.
Lewer said the team examined the physical-chemical properties of certain molecules to find the toxicity of a chemical, which allowed the team to create a program for users to find which chemicals need additional molecules added to make them safer.
“It would be humanity benefiting from the idea of safer pesticides being introduced into the environment,” Lewer said.
Experts in the pesticide studies field said more research into producing safer chemicals can ease public concerns over their safety, like potential exposure to harsh chemicals that can cause serious diseases.
Paul Smith, an associate professor of environmental toxicology at Texas Tech University, said pesticides are designed to kill pests but could poison nontargeted species like humans.
“I think we were always searching for magic bullets, right?,” Smith said. “We would like to be able to design chemicals that will control pests but have incredibly safe profiles with regards to nontarget species, and so that’s the holy grail, to find those chemicals that are effective, where they need to be, but not where we don’t want them to be.”
He said studies about pesticides make it easier to decide which pests the chemicals are intended to kill and the impact of the pesticides on the environment and on native species.
Smith said while growing public concern around the safety of pesticides is valid, there needs to be a more “holistic approach” about other environmental threats like air pollution, urbanization, diminished resources and climate change that also impact native species populations.
“I think anytime we have more knowledge, more understanding of the impacts and where the safety of various chemicals and how they may affect our environmental or native species, then I think that’s a good thing,” he said.
Dana Barr, a professor of environmental health at Emory University’s School of Public Health, said most pesticides are designed to be neurotoxic – containing toxic substances that alter the normal activity of the nervous system – for efficiency, which can cause neurodevelopmental problems and cancer in humans when exposed to active ingredient pesticides.
“Having a safer mechanism for pre-screening, any kind of potential effects to the ecosystem or potential effects to humans certainly helped us in identifying potential long, long-term effects of these pesticides and eliminating their production and use prior to us experiencing that in real life,” Barr said.