BiotiQuest® Gut Health & Probiotics Blog with Martha Carlin

The Longevity of Glyphosate in Soil: Understanding Its Impact on Soil Health and Ecosystems

Martha Carlin | Jun 26, 2023 | 7 minutes read

Glyphosate is one of the most widely used herbicides in the world, known for its effectiveness in killing weeds and unwanted plants. However, there is growing concern about the long-term effects of glyphosate on soil health, human health, and the environment. With conflicting reports on the herbicide's persistence in soil, it can be challenging to determine just how long it lasts and what impact it may have. In this article, we delve deep into scientific research and explore the complex factors determining glyphosate longevity in soil. We examine many variables affecting this chemical's persistence, from soil composition to weather patterns, the risks and implications associated with glyphosate use and its impact on our planet's delicate ecosystem.

Soil microorganisms
One of glyphosate’s most significant environmental risks is the potential impact on soil microorganisms. These tiny organisms play a crucial role in maintaining soil health and productivity, and their disruption can have far-reaching consequences for ecosystems. Glyphosate has been shown to affect microbial activity and composition, leading to changes in soil nutrient cycling and the breakdown of organic matter.

One study published in the journal Environmental Pollution found that glyphosate exposure reduced the abundance of beneficial soil bacteria, including nitrogen-fixing bacteria, which can harm soil fertility. Another study published in Applied Soil Ecology found that glyphosate reduced the activity of soil enzymes responsible for breaking down plant litter, which can slow the decomposition of organic matter and reduce soil carbon storage.

While the effects of glyphosate on soil microorganisms are concerning, researchers are still working to understand the full extent of the herbicide's impact on soil health. It is clear, however, that preserving the balance of soil microorganisms is crucial for maintaining healthy ecosystems and sustainable agriculture.Soil microorganisms play a critical role in the degradation of glyphosate in soil.

Glyphosate is primarily broken down by soil bacteria that possess the enzyme glyphosate oxidase, which converts glyphosate into aminomethylphosphonic acid (AMPA) and glyoxylate. AMPA is a stable compound that can remain in the soil for months or even years. Therefore, the persistence of glyphosate in soil depends on the availability and activity of glyphosate-degrading bacteria. Soil pH, moisture, temperature, and organic matter content are among the factors that can impact the abundance and diversity of soil bacteria, thus affecting glyphosate degradation.


      

Glyphosate herbicides
Glyphosate herbicides come in various formulations, each with a different composition and mode of action. Glyphosate herbicides, such as Roundup, are among the most commonly used herbicides in agriculture and landscaping. They work by inhibiting the shikimic acid pathway, a metabolic pathway found in plants and some microorganisms essential for producing specific amino acids and other essential nutrients. This process eventually leads to the death of the targeted plants. The most commonly used glyphosate formulation is the isopropylamine salt of glyphosate, which has a half-life of about 47 days in soil. The half-life of a chemical is the time it takes for half of the initial concentration to degrade. However, other glyphosate formulations, such as the potassium salt of glyphosate or the mono ammonium salt of glyphosate, may have different persistence rates depending on the soil conditions and application rates. Glyphosate is the active ingredient in Roundup and is known for its broad-spectrum herbicidal activity, meaning it can kill most plants. While glyphosate effectively kills weeds and unwanted plants, it can also adversely affect non-target plants and soil microorganisms.

     


Glyphosate toxicity
Glyphosate has been the subject of much controversy surrounding its potential toxicity to humans and animals. While the herbicide is considered safe by many regulatory agencies, including the U.S. Environmental Protection Agency (EPA), some studies have suggested that it may have adverse health effects. For example, one study published in the journal Scientific Reports found that glyphosate exposure may disrupt the balance of beneficial gut bacteria in animals, negatively impacting their overall health. Another study published in Environmental Health found that glyphosate exposure was associated with an increased risk of non-Hodgkin lymphoma in humans. While the evidence on glyphosate toxicity is still debated, it is clear that the potential health risks associated with the herbicide should be taken seriously.

Glyphosate interactions
Glyphosate interactions with other chemicals and environmental factors can also impact its persistence in soil and potential toxicity. For example, glyphosate has been shown to interact with other herbicides, such as 2,4-D, which can increase its toxic effects on non-target plants and soil microorganisms.

Additionally, glyphosate persistence in soil can be affected by factors such as soil pH, temperature, and moisture levels. Studies have shown that glyphosate can persist longer in acidic soils and under certain weather conditions, which can increase the risk of non-target exposure.

Glyphosate application
Glyphosate is commonly used in agriculture and landscaping and is often used as a spray. The chemical is absorbed through the leaves of plants, disrupting the shikimic acid pathway, a critical process for plant growth and survival. This ultimately leads to the death of the targeted plant. While glyphosate is known for its effectiveness in killing weeds and unwanted plants, the use of this herbicide can have negative impacts on the environment and human health. Glyphosate has been linked to a variety of adverse effects, including increased cancer risk, disruption of the endocrine system, and damage to beneficial insects and soil microorganisms. Source One of the primary concerns associated with glyphosate use is its potential to contaminate groundwater and surface water sources. 

Glyphosate can persist in soil and water for extended periods, leading to the accumulation of this chemical in the environment. This can have far-reaching consequences for human health and wildlife, as glyphosate has been found to cause reproductive problems in amphibians and fish. In addition to environmental concerns, glyphosate use has also been linked to health problems in humans.  The International Agency for Research on Cancer (IARC) has classified glyphosate as a probable human carcinogen, meaning that exposure to this chemical may increase the risk of developing cancer.

Glyphosate is also linked to a variety of other health problems, including developmental disorders, kidney disease, and respiratory issues. Overall, while glyphosate may be an effective herbicide, its negative impacts on the environment and human health cannot be ignored.  As such, it is important to consider alternatives to glyphosate use in soil, and to take steps to minimize exposure to this chemical whenever possible.

     

AMPA Research and How It is Relevant
AMPA (aminomethylphosphonic acid) is a compound formed as glyphosate breaks down in the soil. While glyphosate has been the subject of much research and debate, AMPA has received less attention. However, recent studies have shown that AMPA is also potentially harmful and may negatively impact soil health and microbial communities. Research has found that AMPA can persist in soil for longer periods than glyphosate, with some studies showing it can remain in the soil for up to two years after initial application. This means that even if glyphosate breaks down relatively quickly, the AMPA that is produced as a byproduct may linger in the soil and continue to pose risks. Source Furthermore, studies have shown that AMPA can accumulate in plants and crops, which can have potential health implications for both animals and humans that consume them. Some of the health effects include urinary tract effect, decreased weight gain and abnormal functioning of the central nervous system. Given the potential risks associated with AMPA, it is essential to consider the persistence of glyphosate in the soil and the breakdown of products such as AMPA. This research underscores the need for greater study and regulation of herbicides and pesticides and the importance of exploring alternative, natural solutions for weed and pest control.

 

     

 

How do you neutralize glyphosate in soil?
The best way to neutralize glyphosate in the soil is to increase microbial activity in the soil. Adding organic matter and compost to the soil helps promote microbial growth, which can break down the glyphosate over time. Roundup stays active in the soil particles for a long time.

How long does it take for glyphosate to decompose?
The time it takes for glyphosate to decompose depends on several factors, including soil type, temperature, and moisture levels. In general, glyphosate has a half-life of around 32-47 days in soil, meaning half of the chemical will break down over this period. However, glyphosate residues can persist in soil for much longer, and in some cases, it may take several years for the chemical to degrade fully.

How soon can you plant vegetables after using glyphosate?
The time it takes to plant vegetables after using glyphosate will depend on the type of vegetable and the soil conditions. In general, waiting at least 3 days after applying glyphosate before planting vegetables is recommended. And remember there are potentially harmful impacts on the soil health and your overall health. 
However, it may be necessary to wait longer in some cases, mainly if the soil is sandy or has low organic matter content. And remember there are potentially harmful impacts on the soil health and your overall health.

Does glyphosate accumulate in the soil?
Glyphosate can accumulate in soil over time, mainly if used repeatedly in the same area. The chemical can bind to soil particles, which can make it more difficult to break down. The chemical later affects the root growth of anything planted in the same area. Additionally, glyphosate residues can be carried by soil erosion and runoff, leading to contamination of nearby water sources.

How Yield & Shield help clean up glyphosate toxicity. 
It can be applied to soil any time during the growing cycle. Learn more about how to apply it here Yield & Shield is a soil probiotic that we developed to decontaminate soils from glyphosate and other harmful herbicides that might be present in the soil.

Glyphosate toxicity has a vast majority of residual effects on human cells. Its ability to persist in the environment has an effect on the nervous system, mainly the neurotransmitters which cause oxidative stress. We joined hands with scientists and research on how to clear this residue in the soil and developed Yield & Shield.

Yield & Shield has active microbes that were keenly selected to avail nutrients to the soil, aiding the bioremediation of harmful chemicals like glyphosate which in turn can enhance your health. It can be applied to soil any time during the growing cycle. Learn more about how to apply it here, and enjoy a healthy, bountiful harvest!

With gratitude,

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Martha Carlin, is a “Citizen Scientist”, systems thinker, wife of Parkinson’s warrior, John Carlin, and founder of The BioCollective , a microbiome company expanding the reach of science and BiotiQuest, the first of it’s kind probiotic line. Since John’s diagnosis in 2002, Martha began learning the science of agriculture, nutrition, environment, infectious disease, Parkinson’s pathology and much more. In 2014, when the first research was published showing a connection between the gut bacteria and the two phenotypes of Parkinson’s, Martha quit her former career as a business turnaround expert and founded The BioCollective to accelerate the discovery of the impact of gut health on all human disease. Martha was a speaker at the White House 2016 Microbiome Initiative launch, challenging the scientific community to “think in a broader context”. Her systems thinking background and experience has led to collaborations across the scientific spectrum from neuroscience to engineering to infectious disease. She is a respected out of the box problem solver in the microbiome field and brings a unique perspective to helping others understand the connections from the soil to the food to our guts and our brains.

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