Roundup Pesticide Humans' and Animals' Health Risks

The term pesticides encompass an enormous group of chemicals designed to control, and, ultimately, kill unwanted pests (Natural Resources Defense Council, 2018). Pesticides include insecticides, which are used to control insects, herbicides, which are used to control weeds, rodenticides, which are used to control rodents, fungicides, which are used to control fungi, molluscicides, which are used to control mollusks, and nematicides, which are used to control nematodes (Aktar, Sengupta, & Chowdhury, 2009). These pesticides are the only toxic substances we as human beings intentionally release into the environment to kill living things (Toxics Action Center, 2017). These chemicals that are poisonous, or toxic, to pests also, unfortunately, can be poisonous to humans and can, in turn, endanger human health (Cornell University, 2012). However, many pesticides are relatively non-toxic to humans (Cornell University, 2012). Additionally, massive amounts of benefits have been attained by farmers from the usage of pesticides, specifically herbicides, in the agricultural sector (Aktar, Sengupta, & Chowdhury, 2009). Herbicides prevent agricultural crops from experiencing the effects of pests on their growth and productivity (Hicks, 2016).

Due to the numerous benefits and risks associated with pesticide usage, specifically herbicides, pesticides continue to be a topic that is frequently debated. One herbicide, in particular, seems to garner the most attention from the public and is arguably one of the most controversial pesticides (Zimmer, 2018). That pesticide is known by its brand name, Roundup.

Roundup is an herbicide originally produced by Monsanto and is the world’s most widely used herbicide in the agricultural sector (Zimmer, 2018). Glyphosate, the active ingredient in Roundup, has been used by farmers for more than forty years (Monsanto, 2017). Glyphosate is applied to the leaves of plants to kill both broadleaf weeds and grassy weeds, such as clover, dandelion, thistle, and crabgrass (National Pesticide Information Center, 2010). Glyphosate is a small compound that is often the active ingredient in many herbicide formulations (Zimmer, 2018). Glyphosate comes in many forms. It can come in the form of an acid or a salt and it can come in the form of either a liquid or a solid (National Pesticide Information Center, 2010).

How the chemical glyphosate works is it inhibits EPSP synthase, which is the leading enzyme that plants use to make amino acids (IUPUI Dept. of Biology, 2003). Glyphosate closely resembles the chemical structure of glycine, an amino acid, and, so, because of glyphosate’s and glycine’s similar structures, glyphosate binds the active site of the EPSP synthase enzyme that is crucial to the production of three essential aromatic amino acids: phenylalanine, tyrosine, and tryptophan (IUPUI Dept. of Biology, 2003). Without a functioning EPSP synthase enzyme, the plant can no longer make the essential aromatic amino acids phenylalanine, tyrosine and tryptophan (IUPUI Dept. of Biology, 2003). The plant must synthesize all of the amino acids that are necessary for it to produce protein, so the inhibition of EPSP synthase by glyphosate causes the plant’s cells to “starve” for the three amino acids it can no longer make (IUPUI Dept. of Biology, 2003). All plants use EPSP synthase to make these three aromatic amino acids, so all plants are susceptible to the effects of the active ingredient, glyphosate, in the herbicide, Roundup (IUPUI Dept. of Biology, 2003).

Glyphosate is absorbed by the leaves and the shoots of plants and, once the chemical is absorbed into the leaves and the shoots, it cannot be broken down at all (IUPUI Dept. of Biology, 2003). The glyphosate moves through the plant and accumulates in meristems, otherwise known as areas in the plant where active growth occurs (IUPUI Dept. of Biology, 2003). Ultimately, using glyphosate on a plant results in a lack of protein synthesis in that plant (IUPUI Dept. of Biology, 2003). Without amino acids, the plant will eventually stop growing (IUPUI Dept. of Biology, 2003). The plant tissues will slowly begin to break down due to the lack of protein production (IUPUI Dept. of Biology, 2003). In the end, the plant will die as a result of a lack of nutrients and dehydration a week or so after the initial application of glyphosate (IUPUI Dept. of Biology, 2003).

Glyphosate is known as a “postemergence” herbicide, which means that it cannot be used until after a broadleaf weed or a grassy weed has emerged from beneath the soil (IUPUI Dept. of Biology, 2003). While glyphosate is an extremely effective active ingredient in Roundup, in turn making Roundup an extremely effective herbicide, it is also a non-selective herbicide, meaning it will kill almost any species of plant, both wanted plants, like grass and crops, as well as unwanted plants, like broadleaf and grassy weeds (IUPUI Dept. of Biology, 2003). Roundup can be used to kill a broad spectrum of weeds in a localized area (IUPUI Dept. of Biology, 2003). However, it cannot simply be applied on grass and crops that have weeds growing sporadically throughout them because it will kill the weeds as well as the grass and crops (IUPUI Dept. of Biology, 2003).

While glyphosate will essentially kill any plant it comes in contact with, Monsanto, the original producers of Roundup, was able to create seeds that are resistant to glyphosate and to genetically modify plants to be resistant to glyphosate (Yuan, 2014). This development was extremely effective because it allowed farmers to directly apply glyphosate on fields of crops, instead of just around them, or on them and risk killing every plant except those that are resistant (Yuan, 2014). This was a huge benefit for farmers because producers of other non-selective herbicides have not created seeds that are resistant to glyphosate nor have they genetically modified plants to be resistant to glyphosate.

In addition to that benefit, proponents of the usage of the herbicide, Roundup, have noted numerous other benefits to using this herbicide to kill weeds. One of the most obvious reasons why Roundup has proven to be beneficial for home gardeners and farmers to use is because it controls invasive weed species, which leads to better agricultural yields (Monger, 2016). Unwanted weeds compete with wanted crops for valuable nutrients, sunlight, and water in the soil (Monger, 2016). Weeds attempt to aggressively spread their seeds and release toxins into the soil in the hopes of rapidly increasing in size and number, which leads to weeds eventually taking over fields of crops (Monger, 2016). Because weeds continue to evolve to be able to survive farmers’ attempts to eliminate them, farmers need to use herbicides, like Roundup, to control them. Denying farmers and gardeners the ability to use Roundup would result in agricultural land reverting back to its more natural state, low yields of crops, and, eventually, global food insecurity due to low yields of crops (Monger, 2016). Roundup is beneficial because it keeps these outcomes of weed growth from ever occurring.

Using Roundup makes it unnecessary for farmers to spend time tilling the soil in their fields, which ultimately leads to improved soil management (Monger, 2016). Organic farmers are not allowed to use glyphosate on their crops because of its synthetic origin, so, to control weeds, organic farmers have to till their soil up to five times a year (Monger, 2016). Tilling soil is a process in which soil is stirred, overturned, and broken up, which chops and kills weeds. Tillage disrupts the bacteria living in the soil that aid the soil in the restoration of its nutrients (Monger, 2016). Additionally, tilling soil releases humidity, a valuable resource for plants, from within the soil and leads to higher risks of erosion (Monger, 2016). Roundup has allowed farmers to almost completely eradicate till farming practices and, in turn, has helped farmers to improve their overall soil management, while also saving the time and energy that till farming practices had taken away from them (Monger, 2016).

Proponents of pesticide usage have found that Roundup has a relatively low persistence when compared to other herbicides (Duvauchelle, 2017). Persistence, when describing an herbicide, refers to how long the herbicide continues to work after it has been applied to a garden or a field of crops. A number of different herbicides continue to kill plants or affect plant health for years after the initial application of the herbicide (Duvauchelle, 2017). However, glyphosate in the herbicide, Roundup, gets absorbed into the soil relatively quickly and immediately begins breaking down into a nontoxic substance once it is absorbed (Duvauchelle, 2017). Researchers have found that the average half-life of glyphosate is only about 40 days, which means that after 40 days, half of the glyphosate that is applied to a field will have dissipated (Duvauchelle, 2017). Contrastingly, other pesticides, such as endrin, toxaphene, and mirex have been found to persist in the soil for up to ten to twelve years (Stockholm Convention, 2008). Clearly, glyphosate has a much lower persistence rate than many other herbicides, which is why so many farmers and gardeners alike are drawn to using it.

Compared to other kinds of herbicides, glyphosate is relatively low in toxicity to humans and animals (Duvauchelle, 2017). Glyphosate has an LD50 of around 5,600 mg/kg (Monger, 2016). LD50 refers to the lethal dose that is needed to kill half of the species being studied, usually rats or mice (Monger, 2016). This chemical is less toxic than elements in products we expose ourselves to every day, such as baking soda, coffee, and chocolate (Monger, 2016). Because of glyphosate’s relatively non-toxic nature and all its benefits to agricultural processes, glyphosate can be very alluring to many farmers. However, opponents of glyphosate will argue that, while glyphosate does have many benefits for agriculture, it can adversely affect human health when it is combined with other chemicals in herbicides, specifically Roundup, and not in its pure form.

Monsanto has marketed its product, Roundup, as being safe and environmentally friendly, however, much research has been done that has proven that Roundup can have adverse effects on human health. According to the National Pesticide Information Center, exposure to glyphosate can cause skin irritation, difficulty swallowing, diarrhea, and vomiting (Duvauchelle, 2017). These side effects may seem minor, but glyphosate has been found to have much more dangerous and worrisome effects than just skin irritation and vomiting. Two new studies conducted just recently in 2019 showed links between glyphosate usage and cancer. A meta-analysis of scientific studies done in February of 2019 reported a compelling link between glyphosate-based herbicides, like Roundup, and non-Hodgkin lymphoma (Malkan, 2019). Researchers concluded that workers who are exposed to glyphosate at high levels continuously over decades could suffer an increase in incidences of non-Hodgkin’s lymphoma of 41% (Genetic Literacy Project, 2019). A study conducted in March, 2019 analyzed data gathered from more than 30,000 individuals in the agricultural industry from studies done in France, Norway, and the U.S., and found reported links between glyphosate and B-cell lymphoma, a type of lymphoma that makes up most of the non-Hodgkin lymphomas (Malkan, 2019).

Studies conducted recently have shown that, when exposed to glyphosate, it can have adverse biological effects (Malkan, 2019). A birth cohort study undertaken in Indiana in 2017 found detectable levels of glyphosate in more than 90% of the pregnant women tested and found the levels to be significantly correlated with shortened pregnancy lengths (Malkan, 2019). A study done in Argentina in 2018 found that people who lived in or around agricultural regions were exposed to increased concentrations of glyphosate in the soil and dust. The women living in these regions had higher rates of spontaneous abortion and congenital abnormalities in children,
which suggests that there is a definitive link between environmental exposure to glyphosate and reproductive issues (Malkan, 2019). Glyphosate is toxic to human placental cells (Guest, 2015).

Glyphosate has also been shown to affect numerous other areas of the human body. Glyphosate can induce severe tryptophan deficiency, which can lead to an extreme inflammatory bowel disease that severely impairs the body’s ability to absorb nutrients through the stomach, due to inflammation, bleeding and diarrhea (Guest, 2015). Additionally, glyphosate disrupts sulfate transport from the stomach to the liver, which, over time, may lead to severe sulfate deficiency throughout all the body’s tissues but, more specifically, the brain (Guest, 2015). This sulfate deficiency in the brain has been associated with Lou Gehrig’s Disease, or ALS (Guest, 2015). In farming communities, a strong correlation between Roundup exposure and attention deficit/hyperactivity disorder has been discovered (Guest, 2015). This likely occurs because of glyphosate’s ability to disrupt the thyroid’s hormone functions (Guest, 2015). Lastly, researchers have found that Roundup causes the same type of oxidative stress and neural cell death observed in patients with Alzheimer’s disease (Guest, 2015). Roundup also has been found to affect an enzyme whose dysregulation has also been linked to Alzheimer’s disease (Guest, 2015).

Not only does glyphosate have effects on humans, but researchers have been able to discover that male rats exposed to high levels of glyphosate, either during prenatal or pubertal development, suffer from reproductive problems, including delayed puberty, decreased sperm production, and decreased testosterone production (Guest, 2015). Additionally, a 2017 study linked glyphosate exposure to fatty liver disease in rats (Malkan, 2019). A 2018 rat study reported that exposure to Roundup at levels considered safe significantly altered the stomach bacteria in rats and, when high levels of glyphosate were administered to mice, the stomach bacteria were disrupted and caused anxiety and depression-like behaviors (Malkan, 2019). When scientists transferred a strain of endotoxin-producing bacteria from the stomach of an obese human to the stomachs of mice, the mice became obese (Guest, 2015). Since glyphosate causes a shift in stomach bacteria towards endotoxin-producers, glyphosate exposure may potentially contribute to obesity (Guest, 2015). Additionally, Roundup that travels into bodies of water is extremely toxic to aquatic life (The Cleveland Museum of Natural History, 2019). Glyphosate is not the only chemical in Roundup, it is just the only active chemical (The Cleveland Museum of Natural History, 2019). Herbicide manufacturers must only provide evidence that the active ingredients are safe for the environment (The Cleveland Museum of Natural History, 2015). The inactive chemicals coupled with the glyphosate is what makes Roundup so toxic for aquatic life.

Ultimately, while Roundup and glyphosate seem to be more beneficial for farmers and to the environment, its serious adverse effects to not only human health but animal health as well, make it an herbicide that I find extremely difficult to support. The known risks and the potential risks associated with Roundup most definitely outweigh the few benefits associated with it. Numerous countries across the world, like Portugal, Netherlands, Italy, and Brazil, have either restricted or completely banned the use of Roundup and many other countries are in the process of doing so because of the serious risks Roundup imposes on human beings and animals (Baum, Hedlund, Aristei, & Goldman, 2019). Many countries are still fighting to maintain the usage of Roundup in their countries’ agricultural sector. The use of the herbicide, Roundup, continues to be a strongly debated topic and, while the proponents and opponents of this issue may never see eye to eye, the knowledge that has been gained as a result of research studies on humans and animals has shown that Roundup poses serious threats to humans’ and animals’ overall health.