Glyphosate : Weed Killer or Environment Wrecker?
Introduction, Connection & brief History: - Weeds and Glyphosate
Weeds have existed from the time organic carbon content soil formed naturally on earth. It takes a relatively short duration for weeds to germinate, grow, produce a flower and seed, before they perish. Weeds do a vital job in ecosystems: they quickly establish themselves in the soil as well as protect and restore soil that has been exposed by natural and human-induced disturbances. It takes very little for weeds to sprout and grow. They grow in all kinds of soil surfaces and in minimum suitable conditions too.
Weeds behave true to the old saying, “Nothing grows like a weed”.
Apart from improving the quality of the soil, weeds also act as a natural pest control and enhance crop pollination. Moreover, some weeds are also used as food and medicine. However, even with all its benefits, weeds are not beneficial for agriculture. Ever since formal farming began about 13,500 years ago, weeds have always been a worry for farmers. It is said that weeds are the costliest category of agricultural pests. Weeds cause more yield loss and add more to farmers’ production costs than any other causes.
Monsanto developed the use of glyphosate to kill weeds in the early 1970s, which was patented in 1971. They first brought it to market in 1974, under the brand name ‘Roundup’, and thereafter it quickly became the leading pesticide in the global agro-chemical market.
What is Glyphosate?
Glyphosate is a broad-spectrum chemical herbicide that is used world over. It is used to kill weeds and unwanted plants that threaten the growth of crops and other native plants by competing for water, sun, and soil nutrients. Glyphosate is usually available in the form of solid, liquid concentrate, and read-to-use liquid as well.
While aerial sprays as well as shielded and hooded sprays are the most common methods for administering glyphosate, they are also available in the form of sponge bars, injection systems, wide applicators, and controlled droplet applicators. Glyphosate herbicide is used for an array of crops including corn, cotton, soybean, citrus crops, leafy vegetables, sugar beet, bulb vegetables, tube vegetables, legume vegetables, etc. Apart from agricultural use, glyphosate is also used in residential and commercial settings.
How Glyphosate Works?
Glyphosate is derived from an amino acid named glycine. When glyphosate is sprayed on the plant, it spreads to every part of the weed or unwanted plant through the leaves. It travels through every cell and seeps into the stems and the roots, thus causing the decay of the entire plant in 2-3 weeks. As glyphosate effectively kills unwanted plants and weeds, it is a widely used herbicide all over the world.
What are the Disadvantages of Glyphosate?
Although glyphosate is considered a safe herbicide by the EPA, i.e. the United States’ Environmental Protection Agency, several recent studies have pointed out the side effects of this pesticide.
Is Glyphosate Harmful to the Environment?
Glyphosate has an affinity to bind to soil particles and thus mostly accumulates in the top-soil layers. However, processes like surface runoff, drift, and vertical transport in soil may transport it to groundwater, surface water, and water sediment. When soil and water are affected, it can affect the entire ecosystem. Several studies show the impact of glyphosate on plants, soil, microbes, humans, animals, and other organisms as well.
Impact on Plants
The main problem with glyphosate is that it is a non-selective herbicide. This means that the herbicide can have the same effect on native plants or crops on the land as the weeds and unwanted plants. Even if the pesticide is not directly sprayed on these plants, traces of glyphosate can spread to the nearby plants. Moreover, a large portion of the spray can also reach the soil and travel to the main crops or non-targeted plants through the roots. Moreover, the aerosolized droplets of this herbicide can move like a cloud and cause harm to plants or crops of neighboring fields, especially on a hot and humid day.
Impact on Soil
Apart from causing harm to the main crops and plants, long-term or continuous use of glyphosate on the same land can also harm the soil. Earlier it was believed that glyphosate binds to soil particles and remains only in the top layer of the soil. However, glyphosate leaching into the lower layers of soil is possible in certain types of soil and weather conditions. In such cases, glyphosate can seep into surface water, groundwater, and even in drainage water.
As the health of the soil is extremely important for growing good crops, the presence of glyphosate in it can have hazardous effects. Moreover, the residue of glyphosate remains in the soil for several months and even years. As glyphosate accumulates in the soil for a long period, it can not only harm the quality of the food crops but also the environment. Glyphosate “locks up” manganese and other minerals in the soil, which cannot be utilized by the plants that need them. It is also toxic to rhizobia, the bacterium that fixes nitrogen in the soil.
Impact on Microbes
Microbial activity is one of the most important things that are affected by prolonged exposure of glyphosate to the soil. Present in the form of fungi and bacteria, microbes are a part of the plant ecosystem and help to improve their mineral nutrition. Microbes not only provide the plants with nutrition but also protect them against drought and disease.
Studies have found that long-term use of glyphosate can alter the structure, function, and diversity of the communities of microbes that are present in the soil. They attack the fungi present on the roots of the plants or crops, thus preventing the crops to receive adequate nutrition. Extended use of glyphosate changes the balance between good and harmful microbes in the soil. Due to this, crops have lost the ability to fight soil-borne pathogens, which increase the chances of crop diseases.
Impact on Earthworms
Just like soil is compromised due to the use of glyphosate, earthworms are also affected by the use of this pesticide. Earthworms are essential for soil health; the burrowing action of earthworms increases soil porosity, which enhances root development. Earthworms also boost soil fertility as they help in producing phosphorous, magnesium, nitrogen, and potassium.
Although several studies have proved that the use of glyphosate does not affect earthworms, several others prove the opposite. It was observed that the activity of a specific species of earthworm stopped while the reproduction of another species was reduced after the use of this herbicide. As the activity of earthworms reduced, it also led to increased concentrations of phosphate and nitrate in the soil.
Impact on Amphibians and Aquatic and Marine Organisms
As glyphosate can flow into lakes, rivers, streams, and other water bodies, it can harm amphibians and aquatic animals too. These animals can ingest the chemical herbicide through their skin as well as by feeding on things contaminated by it. Several studies have shown that glyphosate can affect the growth, reproduction, metabolism, and behavior of aquatic animals. A lab experiment on frogs that were exposed to glyphosate revealed several shocking results like shortening of the body, facial and cranial malformations, defective eyes, etc. Another study also showed that the herbicide harmed the mortality rate of tadpoles.
A similar effect was seen in aquatic animals and microorganisms, which are a crucial part of the marine ecosystem and food chain as well. It was observed that glyphosate exposure led to a lot of problems including lesser life expectancy, lower reproduction rate, increased chances of diseases, and lesser population too.
Impact on Humans and Animals
Apart from plants, soil, and microbes, glyphosate also poses health risks to humans and animals. Animals can get affected when they eat crops or plants sprayed with glyphosate. They can ingest the pesticide even when they eat the prey that has fed on the glyphosate-treated crops or plants.
The greatest risk is to the farmers who spray the herbicide on the plants or crops. When they spray glyphosate, they are likely to inhale it and at the same time absorb a large amount of the chemical through their eyes and skin. The risk becomes higher when they smoke or eat without washing their hands after spraying the pesticide.
It may also irritate the eyes, nose, throat, and skin. Superficial cornea injury is also one of the side effects of glyphosate exposure to the eyes. Inhaling or swallowing glyphosate can lead to burns and increased saliva to the throat and mouth. Diarrhea, nausea, and vomiting are some of the major effects of inhaling and swallowing the pesticide.
The greatest danger is caused by the lack of awareness due to limited information provided to the farmers or handlers about the direct harmful effects and permanent damage to the them. Agencies are making very little efforts towards educating and making farmers aware of the ill effects of glyphosate.
The problem is that there are not many studies that prove that glyphosate is risky for humans and animals. The EPA describes it is safe for humans and also non-carcinogenic. However, a study conducted in 2015 by the World Health Organization’s (WHO) International Agency for Research declared glyphosate as “probably carcinogenic to humans”, based on their conclusion on observational studies, animal studies, and test tube studies. It suggested that prolonged exposure to glyphosate can probably cause cancer, especially non-Hodgkin lymphoma.
During the study, it was seen that glyphosate disrupted the endocrine system, creating hormonal imbalance. Even at low-level exposure to glyphosate, oxidative damage to the DNA is high and can cause cellular mutation. The study also showed that high-level exposure to glyphosate can induce breast cancer. A lab study also suggested hemolysis and oxidation of hemoglobin in human blood due to glyphosate.
Unfortunately, there are very limited access to information studies that link glyphosate with cancer on the web.
As per an article last April 2021, by Craig Pittman, a native Floridian working at Tampa Bay Times & having won numerous state and national awards for his environmental reporting.
“Dr. Denslow’s friend is far from the only American peeing Roundup. In 2016, a study by the University of California, San Francisco, found glyphosate residue in 93 percent of the urine tested. (On second thought, don’t ask your doctor whether Glyphosate is right for you — it’s not.)
Bayer has repeatedly denied that Roundup causes human health problems. That claim has been much harder to maintain in the face of more than 13,000 lawsuits blaming exposure to glyphosate in Roundup for users developing cancer, Bloomberg News reported last year. So far, Bayer has lost three of those cases, resulting in combined damages of $191 million.
As a result, Bayer agreed to pay $39.5 million to settle allegations that its Roundup ads included misleading information about the health risks to both humans and animals.
The EPA initially labelled Roundup a cancer-causing chemical in 1985, but then, during the Reagan administration, flip-flopped and whatever else transpired that despite all the lawsuits, the EPA still labels it as safe to use and does not regulate purchases.”
Moreover, the negative impact of glyphosate on humans is not limited to cancer. A study conducted on rats shows a potential effect of glyphosate on kidney and liver malfunction as well. During the study, a change in the structure and function of kidneys and liver of the rats that were exposed to low doses of glyphosate were seen. They were also found to have developed non-alcoholic fatty liver disease due to exposure to glyphosate, which eventually led to liver dysfunction.
Traces of glyphosate were seen in the urine of a large number of people in Europe, indicating that the traces of this herbicide would be present in the bodies of most people in the continent. However, scientists are unsure as to how it entered into the system. There is little to no research on how indirect exposure to glyphosate (for example, through foods) can affect humans. Moreover, the presence of glyphosate in foods is rarely tested.
It must be agreed that there are no huge bodies of studies that focus on the effect of glyphosate and the environment. However, most of the research done in this area indicates that it has the potential to harm the environment. The Food and Drug Administration (FDA) of the UN raised concerns over the effects of the use of glyphosate on the food chain.
From whatever research did till now, it can be understood that glyphosate can hurt the entire ecological system. When the pesticide is sprayed on the plants, it can spread from the plants to the soil and water, thereby affecting all the living organisms that are part of the ecosystem.
The concerning fact is that as glyphosate is a highly used herbicide all over the world, and its side effects have been built up over several decades. Hence, it is important to take the necessary steps to reverse the damage before it becomes too late. To decrease the effect of the herbicide, the dependence on it must be reduced. Several countries have banned or have started phasing out the use of glyphosate.
Apart from this, more research on the impact of glyphosate on food as well as the ecosystem needs to be carried out, and we should rally governmental and all available resources such as the WHO as well as environment-related NGOs and agencies to increase the awareness about the ill-effects of glyphosate, right down to the handler. After all, it concerns us: what we consume, our health, our planet and its future, and the future of life on earth.
Weeds as a matter of Interest
We also need to acknowledge that fact that if it were not for weeds, the world would have lost lot more topsoil than it has to date, and all living inhabitants of our planet would have suffered mass starvation, as some weeds are sources of food as well.
New studies on weed management that establishes how to weed and when to weed is extremely crucial to minimize the damages caused due to excessive weeding. This is a topic that needs a separate post.