The Lowdown On Weed Killer Chemicals

What are the active ingredients in weed killers? We'll discuss the compounds in weed killers and their safety. Learn everything you need to know.

Weed Killer Chemicals: What You Need To Know About Safe Use

Up until about 120 years ago, being able to control the weed growth within a crop any way other than by physically removing each weed, was unimaginable. At that time, any chemical agent used to try to kill weeds would also kill the crops themselves. Weeds and the crops that they plagued, were too closely related biologically to allow for the selective removal of one without harm to the other. It wasn’t until the 1940s that phenoxyacetic acid herbicides were perfected and then successfully used to remove broadleaf weeds from cereal crops, such as corn, without harming the corn itself, thus beginning a new science of herbicide technology that became widely used after World War II.

How Chemical Weed Killers Become Widely Used Around the World

The use of chemical weed killers became standard farming practice after the 1950s and resulted in dramatic changes worldwide. Suddenly fruits and vegetables that had previously only been affordable to the rich, or available to those who owned their own farms, were both available and affordable, and easily accessed from every supermarket shelf.

Then in 1974, a patent was filed for a new chemical compound known as glyphosate and even more dramatic changes took place worldwide. Countries with populations that had previously faced chronic problems with starvation were suddenly able to access such life-giving crops as corn, rice, and soybeans. This chemical allowed previously unheard of crop yields, bringing life-saving changes to many underdeveloped countries.

Is Popular Weed Killer Glyphosate Safe?

In 2015 a study by the World Health Organization found that Glyphosate was “probably carcinogenic.” Then the very next year the European Food Safety Authority stated that their own studies showed that Glyphosate was not likely to cause cancer in humans. Since that time, the conflicting information has been hotly debated in both the scientific communities and on social media, with no simple answers found as of yet.

While some studies show significant cancer risks, including an evaluation of studies conducted by the University of Washington which showed an increased risk of non- Hodgkin’s Lymphoma by 41 percent, others don’t seem to result in the same findings.

One thing, however, is undebated. If Glyphosate is banned, as some organizations are now demanding, farming as we know it would suddenly be forced back to now-outdated methods resulting in substantially less yield and higher prices for produce and cereal products worldwide.

Another undebated outcome of a possible ban of Glyphosate would be farmers forced to use a mix of other chemical compounds which could result in even more potential hazard to humans.

Are the Weed Killers we Use on Our Lawns Safe?

The use of chemicals allowed on lawns is regulated by state and local jurisdictions. The two chemical compounds most commonly found in the weed killers we use on our lawns are 2,4- dichlorophenoxyacetic acid, and glyphosate. Studies of occupational exposure to these chemicals have found a positive correlation with certain types of cancer.

A 2013 study examined the levels of pesticides found in dog urine after lawns were treated with these chemicals and found that levels remained high up until 48 hours after lawns were treated, despite most warning labels stating that it was safe to be in contact with the lawn six to 24 hours after treatment.

Despite those findings, a professor of weed science at Mississippi State University maintains that normal exposure to these chemical weed killers are harmless because they are formulated to work on plant enzymes and not human.

Most weed killers sold for residential use are required by law to break down in the soil in 14 days or less. According to the warning labels of these products, it is safe after that time period to plant gardens growing edibles in areas treated by residential weed killers.

In effect, it seems that to date we can choose to feel either reassured that no absolute data has been found to prove that weed killers are harmful to our health in typical human exposures, or we can choose to feel anxious that no studies have proven them to be absolutely safe either.

According to a biosciences professor at the University of Central Lancashire, the conflicting nature of the studies at this time indicates a serious need for further, well-structured studies based on typical exposure levels, as the available studies to date are small and inconsistent.

Resources— ScienceDirect, CNN, The Washington Post, Gardening Know-How