Herbicides in Our Natural Water Bodies

Herbicides in Our Natural Water Bodies

Herbicides in our natural water bodies. Have you ever visited a natural waterbody and noticed plants dying along the shoreline? This may be due to the spraying of synthetic herbicides. What are herbicides and how do they affect the health of our local environments? Could local groups remove invasive plants rather than spray toxic chemicals for removal? Read on to learn more about this issue and what you can do to help.

What are Herbicides?

Herbicides, commonly known as weedkillers, are chemicals that destroy plants or inhibit their growth. The two kinds of herbicides are selective and non-selective herbicides. Selective herbicides will kill certain plants while keeping others alive while non-selective herbicides will kill most plant species (1). According to the United States Environmental Protection Agency, “Herbicides can act by inhibiting cell division, photosynthesis or amino acid production or by mimicking natural plant growth hormones,” (2).  Herbicides are usually sprayed directly onto foliage, soil, and aquatic systems.

Early Known Herbicides 

A few of the most early known weed killers were blue vitriol (copper sulfate), sulfuric acid, and carbon bisulfide (13). Each of these weed killers had drawbacks such as not working in certain climates, leaving a foul odor behind, and being dangerous to humans. The multimedia organization called the Ganzel Group stated, “The first synthetic organic chemical for selective weed control to come out of the labs was introduced in 1932. Its chemical name was 2-methyl-4, 6-dinitrophenol” (13). Research done by the University of Caen and the University of Burgundy concluded that glyphosate-based herbicides such as the popular “Round-Up” cause damage to DNA and disrupt endocrine in human cell lines (14).

What are Glyphosates?

Glyphosates are an herbicide designed to kill plants that compete with crops such as weeds. According to the National Center for Biotechnology Information, “Glyphosate is a phosphonic acid resulting from the formal oxidative coupling of the methyl group of methylphosphonic acid with the amino group of glycine. It is one of the most commonly used herbicides worldwide, and the only one to target the enzyme 5-enolpyruvyl-3-shikimate phosphate synthase (EPSPS)” (11). Whether or not glyphosates cause cancer is a controversial question that scientists still struggle to answer. 

Organizations such as the World Health Organization and The International Agency for Research on Cancer categorize glyphosates as possibly carcinogenic (17). The California Office of Environmental Health Hazard Assessment took a more direct stance against glyphosates stating that glyphosates were, “known to the state of California to cause cancer,” (18). Farmers spray glyphosates onto different crops such as corn, soybeans, wheat, barley, oats, and more. Anresco Laboratories in San Francisco tested 28 samples of products from the companies Quaker and General Mills (19). The two companies claimed that there was no cause for concern for consumers because their products met the legal standard of glyphosate usage (20). However, according to the Environmental Working Group, ”almost all of the samples tested by EWG had residues of glyphosate at levels higher than what EWG scientists consider protective of children’s health with an adequate margin of safety.” One product, the Quaker Oatmeal Squares breakfast cereal, was found to be 18 times higher than the EWG’s children’s health benchmark (4). Among the samples that EWG tested were Quaker and General Mills products such as Quaker’s Old Fashioned Oats and General Mills’ Cheerios cereal. 

The Roundup Myth

Roundup is a brand of glyphosate-based herbicide manufactured by Bayer. Scientists debate whether or not Roundup is harmful to humans. The main component in Roundup, Glyphosate, was classified as a possible human carcinogen by the World Health Organization’s International Agency for Research on Cancer  (7). However, the U.S. Environmental Protection Agency and European Food Safety Authority determined that glyphosate was not carcinogenic. Several lawsuits against Bayer have been filed by customers claiming that they developed non-Hodgkin’s lymphoma after using Roundup for years (). Overall, scientists seem to agree that more research is necessary about glyphosate and its toxicity levels. 

Herbicide Usage in Florida’s Natural Springs

Excessive use of herbicides is not a new problem to our state parks that host our Florida springs like Wekiwa Springs State Park in Apopka, FL. A 2002 article by the Orlando Sentinel revealed that the US Army Corps of Engineers would travel by airboat and spray herbicides into the river (3). According to the Journal of the National Cancer Institute, “some findings have linked herbicide exposure with cancers of the colon, lung, nose, prostate, and ovary as well as to leukemia and multiple myeloma,” (4). Many residents surrounding the Wekiva river were unaware of the potential risks with one woman saying that she used the river water for cooking and drinking (3). Excessive utilization of herbicides in the spring may induce eutrophication of the stream (5). Eutrophication is excessive enrichment of nutrients into a body of water, usually from run-off, that causes dense plant growth and death for some animals from lack of oxygen.

Manatees at Risk

We aren’t the only ones at risk of health issues through the consumption of glyphosates. Researchers from organizations such as the Aquatic Animal Health Program at the University of Florida, the Wetland and Aquatic Research Center, Clearwater Marine Aquarium, and more participated in research to find how glyphosates affected Florida manatees (21). According to their research, “Glyphosate was present in 55.8% of the sampled Florida manatees’ plasma.” Glyphosate enters Florida freshwater springs, lakes, and rivers as a result of run-off from farming nearby or from spraying glyphosate to control aquatic weed populations. Besides habitat loss, food shortages, and boat accidents, manatees suffer from cold stress syndrome. 

During the winter months, manatees seek warmer freshwater in springs or power plant outflows that have industrial warm water (21). Unfortunately, manatees are exposed to different pesticides and herbicides in these environments. Glyphosate is the most commonly used herbicide in the world, so there’s no surprise that manatees have such high levels in their plasma. The chronic exposure to glyphosate-based herbicides may have consequences on the immune and renal systems of Florida manatees that are made worse by the environmental obstacles they already face.

Legal Herbicides and Their Negative Effects

Herbicides are commonly used to kill unwanted vegetation but many don’t understand the negative effects that they have on the environment. The U.S. Fish and Wildlife Service and National Wildlife Refuge System stated, “Persistent herbicides can remain active in the environment for long periods of time, potentially causing soil and water contamination and adverse effects to non-target organisms. In some cases, compounds that result from herbicide degradation may continue to be significantly toxic in the environment,” (10).  Here is a list of some legal herbicides and their active ingredients in the state of Florida:

  • Rodeo – Glyphosate
  • Clipper – Flumioxazin
  • Cutrine Plus – Copper
  • Galleon – Penoxsulam
  • Sonar/Avast – Fluridone

Herbicide Alternatives:

The best way to avoid these dangerous herbicides is to find useful alternatives. Some alternatives to herbicides are:

  1. Mechanical removal (removing plants by hand) *Most eco-friendly alternative*
  2. Vinegar/Citric Acids
  3. Corn Gluten
  4. Phytotoxic oils such as peppermint or citronella
  5. Herbicidal soaps

What Can You Do?

There are a few ways that you can help protect your community and Florida manatees from the dangerous effects of glyphosates. First, endeavor to eat more organic foods. Organic farming prohibits the use of glyphosates so buying more organic foods will limit your exposure (17). Secondly, encourage local and state governments to monitor glyphosate levels in Florida water bodies, regulate those levels, and determine the source of the herbicide.  Awareness is the first step that can lead to action to protect our health and that of our beloved wildlife. Thirdly, organize a group of volunteers to reach out to these state parks to lead mechanical plant removal events. You can contact them to create “Invasive Plant Removal” volunteer opportunities to remove these plants by hand instead of by chemical. Also, your local environmental non-profit like IDEAS For Us may have events already planned for you to attend. Check out our IDEAS For Us Orlando Facebook events to get active in the Central Florida community.

Help spread awareness by sharing this blog post with friends, family, and members of your community. Besides that, you can help organizations that are fighting against pesticide use such as Beyond Pesticides through donations, volunteering, or sharing their work with others. We can encourage further research into herbicides and the dangers they may pose to humans. Discourage the excessive use of herbicides in our state parks by protesting or making a claim to the local government. As a community, we can organize volunteer groups to help clean our state parks and maintain the sacred springs. Together, we can find sustainable solutions to today’s environmental issues and take action to save the planet.


  1. https://www.gardeningknowhow.com/plant-problems/weeds/using-herbicide-in-gardens.htm#:~:text=Herbicides%20are%20chemicals%20that%20kill,use%20herbicides%20safely%20and%20effectively.
  2. https://www.epa.gov/caddis-vol2/caddis-volume-2-sources-stressors-responses-herbicides
  3. https://www.orlandosentinel.com/news/os-xpm-2002-02-18-0202180020-story.html
  4. https://pubmed.ncbi.nlm.nih.gov/1460670/
  5. https://floridadep.gov/rcp/aquatic-preserve/locations/wekiva-river-aquatic-preserve
  6. https://oceanservice.noaa.gov/facts/eutrophication.html
  7. https://www.iarc.who.int/featured-news/media-centre-iarc-news-glyphosate/
  8. https://topclassactions.com/canada/roundup/is-roundup-harmful-to-humans/
  9. https://www.usnews.com/news/national-news/articles/what-to-know-about-glyphosate-the-pesticide-in-roundup-weed-killer
  10. https://www.fws.gov/invasives/stafftrainingmodule/methods/chemical/impacts.html#:~:text=Persistent%20herbicides%20can%20remain%20active,significantly%20toxic%20in%20the%20environment.
  11. https://pubchem.ncbi.nlm.nih.gov/compound/Glyphosate
  12. https://www.baumhedlundlaw.com/blog/2016/april/is-there-a-safe-alternative-to-roundup-/
  13. https://livinghistoryfarm.org/farminginthe30s/pests_06.html#:~:text=The%20first%20synthetic%20organic%20chemical,large%20seeded%20crops%20like%20beans.
  14. https://www.sciencedirect.com/science/article/abs/pii/S0300483X09003047
  15. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4947579/#:~:text=Glyphosate%2Dbased%20herbicides%2C%20such%20as,animals%20(88%2C%2090).
  16. https://www.the-scientist.com/news-opinion/how-toxic-is-the-worlds-most-popular-herbicide-roundup-30308
  17. https://www.webmd.com/cancer/herbicide-glyphosate-cancer
  18. https://oehha.ca.gov/proposition-65/crnr/glyphosate-listed-effective-july-7-2017-known-state-california-cause-cancer
  19. https://www.ewg.org/news-insights/news-release/roundup-breakfast-part-2-new-tests-weed-killer-found-all-kids-cereals
  20. https://www.ewg.org/news-insights/news-release/ewg-responds-general-mills-and-quaker-oats-legal-not-same-safe
  21. https://www.sciencedirect.com/science/article/pii/S0160412021001185

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