Dispersal chemical of the herbicide dicamba from crops into the atmosphere is known as “dicamba drift,” and it has been shown to unintentionally harm nearby plants. Dicamba is combined with other chemicals, usually amines, to “lock” it in place and stop it from volatilizing, or changing into a vapor that can move more readily in the atmosphere air.
New research has now shed new light on this story by establishing for the first time that these amines themselves volatilize, frequently more than dicamba itself, in the lab of Kimberly Parker, an assistant professor of energy, environmental, and chemical engineering at Washington University in St. Louis.
On September 23, the journal Environmental Science and Technology published their findings.
The processes that result in dicamba drift may be explained by the volatilization of amines when used in combination with dicamba. However, amines are also utilized in other herbicides, such as glyphosate, the most widely used herbicide globally. The researchers discovered that amines still volatilized despite the herbicide.
Amines themselves have the potential to generate compounds that promote cancer, so if they are released into the atmosphere, they may be harmful to human health. They also have an impact on atmospheric chemistry and climate. The scientific literature is replete with studies examining the methods by which they are released into the atmosphere due to their potential hazards and prevalence, with the exception of those examining their use in herbicide-amine combinations.
Amines can also react to create particulate matter, which is made up of microscopic particles that can enter the body by inhalation, according to Parker. They have an impact on temperature and the chemistry of the atmosphere. “Those particles are also poisonous and carcinogenic.”
Despite the fact that vast amounts of herbicide-amine mixes are sprayed onto crops all over the country, Parker said: “Researchers have looked at industrial applications, animal operations, and environmental sources of amines.”
We were shocked to learn that this source had been ignored.
Her lab has studied the use of amines with herbicides in agriculture. The amines were included in such instances to prevent the pesticide dicamba from volatilizing. However, the method frequently proved ineffective, and the dicamba ended up drifting to surrounding fields.
When conducting earlier research on the volatilization of dicamba from dicamba-amine combinations, Parker’s lab PhD student Stephen Sharkey pondered, “If the dicamba is volatilizing, what’s happening to the amine that’s supposed to be there inhibiting the volatilization process?”
Sharkey investigated how the concentration of amines changed over time in the presence of several herbicides to find out. The outcomes? The amines from the herbicide-amine mix are volatile in all mixtures. By capturing and measuring amines from the air, Sharkey collaborated with Brent Williams’ lab, an associate professor of energy, environmental, and chemical engineering, to determine that the amines were coming from herbicide-amine combinations and entering the gas phase.
Parker noted that amines are used with other herbicides, such as 2,4-D and the commonly used glyphosate, in agricultural contexts in addition to dicamba.
Sharkey measured the amount of amines that were actually entering the atmosphere, which needed some sleuthing in addition to experiments. He made use of two different sets of data, including survey information from American farmers that revealed which individual amines were used in conjunction with which herbicides and approximated rates of herbicide application.
According to Sharkey’s research, the usage of herbicides causes an annual release of amines in the United States of around 4 gigagrams (4,000 metric tons).
Parker was a little taken aback by the results herbicide chemical is in the air, not just because the chemistry doesn’t seem to indicate that amines volatilize in this manner, but also for more pragmatic reasons.
The various methods by which amines enter the atmosphere have been extensively studied, she said. Although much work has gone into studying the origin of amines, research into their potential application as herbicides hasn’t been done yet.
