Have there been any studies linking the use of glyphosate in Hawaii with damage to coral reefs and ecosystems?

Glyphosate use in Hawaii: Glyphosate is a herbicide that has been widely used in Hawaii and other areas for the control of weeds. While glyphosate has been generally considered to be less toxic to aquatic life than other herbicides, there have been some studies that have suggested that glyphosate may have negative impacts on coral reefs and other aquatic ecosystems.

What Products Contain Glyphosate?  According to EPA.gov website, “Products containing glyphosate are sold in various formulations, including as liquid concentrate, solid, and ready-to-use liquid. Glyphosate is used in products such as Roundup® to control weeds in both agricultural and non-agricultural settings. Glyphosate can be applied in agricultural, residential and commercial settings using a wide range of application methods, including aerial sprays, ground broadcast sprayers of various types, shielded and hooded sprayers, wiper applicators, sponge bars, injection systems, and controlled droplet applicators”.

“Agricultural uses include corn, cotton, canola, soybean, sugar beet, alfalfa, berry crops, Brassica vegetables, bulb vegetables, fruiting vegetables, leafy vegetables, legume vegetables, cucurbit vegetables, root tuber vegetables, cereal grains, grain sorghum, citrus crops, fallow, herbs and spices, orchards, tropical and subtropical fruits, stone fruits, pome fruits, nuts, vine crops, oilseed crops, and sugarcane”. (Source https://www.epa.gov/ingredients-used-pesticide-products/glyphosate)

Agricultural Chemicals in the environment: Agricultural Chemicals can contaminate soils and soak into groundwater. Chemicals can also wash off agricultural lands during rains, and also affect waterways and wetland ecosystems, and marine life, when overspraying occurs. On Maui, sugarcane burning of glyphosate-sprayed sugarcane was also a possible mechanism for spreading these chemicals over long distances.

There is growing evidence that glyphosate, a widely used herbicide, may have negative impacts on coral reefs and other aquatic ecosystems. Glyphosate has been shown to have toxic effects on a variety of coral species and may disrupt the delicate balance of coral reef ecosystems by altering the distribution and abundance of coral-associated organisms. 

Click here to learn more about how agricultural chemicals can affect ecosystems and reefs.

Here are a few articles that have investigated the potential impacts of glyphosate on coral reefs and aquatic ecosystems:

  • Effects of glyphosate herbicide on the gastrointestinal microflora of Hawaiian green turtles (Chelonia mydas) Linnaeus, https://www.sciencedirect.com/science/article/abs/pii/S0025326X17309876
  • Additive effects of the herbicide glyphosate and elevated temperature on the branched coral Acropora formosa in Nha Trang, Vietnam, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5978828/


Glyphosate was widely used in Sugar Cane Production: 

Glyphosate was a herbicide that is commonly used in sugar cane farming on Maui and other parts of the world to control weeds and unwanted vegetation. In sugar cane farming, glyphosate is typically applied as a pre-emergent treatment, before the sugar cane is planted, to control weeds and other unwanted vegetation in the fields. Glyphosate was also applied as a desiccating (drying) agent pre-harvest and was often sprayed from helicopters onto large areas of sugar cane.

Glyphosate was one of the most commonly used herbicides in the Hawaiian sugarcane industry, and it is typically applied as a pre-emergent treatment to control weeds and other unwanted vegetation in the fields. The study also found that in Maui, the average annual usage of glyphosate in sugar cane farming ranges between 0.8 – 1.2 pounds per acre.

Glyphosate and other herbicides are commonly found in surface water and groundwater in the Hawaiian Islands, including Maui, and their presence can have negative impacts on aquatic life and human health.

Glyphosate and other potentially harmful chemicals are still being used in large quantities today on Maui: Glyphosate is one of the chemicals being used for the production of seed Corn and many other crops. It is important to ensure that the use of glyphosate and other herbicides is done in a way that minimizes the risk of negative impacts on the environment and human health.


A 1999 TerraGator 8103 applying herbicide on pre-emergent crops
Pl77, CC BY-SA 3.0, via Wikimedia Commons

Further Reading: 

  • Statewide pesticide Sampling Pilot Project: https://www.mauicounty.gov/DocumentCenter/View/94671/Hawaii-2013-2014-Pesticide-Sampling-Pilot-Project-Water-Quality-Findings
  • Crop Profile for Sugarcane in Hawaii , https://ipmdata.ipmcenters.org/documents/cropprofiles/HIsugarcane.pdf