by Kevin Yuan

Since the late 1900’s Monsanto Corporation, an organization focused on agricultural biotechnology produces biotechnology and herbicides for different plants such as corn, cotton and vegetables. Monsanto is considered one of the Big 6 Biotech Corporations because of its prominence in the agricultural market. In the late 1970’s, Monsanto Corporation introduced a new chemical called glyphosate for agricultural distribution in the United States. Glyphosate, the chemical soon branded by Monsanto as Roundup is a widely used herbicide used to kill a variety of plants includes grasses, weeds and woody plants.[1].

John E. Franz first discovered Glyphosate’s agricultural use and discovered glyphosate’s mechanism through his work with Monsanto.[2] Glyphosate kills plants specifically by disrupting the production of specific aromatic amino acids, which are the building blocks of protein that any organism requires to live; these 3 amino acids are phenylalanine, tyrosine and tryptophan. Although the biochemical mechanism involved with Glyphosate’s function is complex, it is important to understand that the glyphosate functions by inhibiting a particular enzyme, EPSPS, which plants need to synthesize essential amino acids that are essential for life.

Glyphosate essentially kills any plant, so random distributing of the product would kill every plant exposed. Initially, many farmers were forced into position where they had to use Roundup as a herbicide or a weed killer, but were limited to apply Roundup only around their planting area to prevent killing of favorable crops. However, new development from Monsanto Corporation was able to produce seeds and genetically modify plants to be resistant to glyphosate. This progress proved to be extremely effective as it allowed farmers to directly apply glyphosate on the fields, instead of just around them, killing every plant except those that are resistant.[3] This is important because weeds and unwanted plants compete for essential nutrients, light and water. Competition for these vital resources, weeds deter optimum growth of favorable plants. Weeds also serve as vectors/carriers for different plant diseases and can potentially transmit plants them that are wanted, possibly destroying an entire field, putting farmers in an economic bind. Glyphosate is also often sprayed on sidewalks and in crevices in sidewalks where weeds grow. Weed management systems with glyphosate resistant crops have had a profound effect, with many benefits such as improved yield and profitability.

This use of glyphosate in weed control not only proved to be a great economical benefit but also “improved the safety of farmers and weed control operators.” Glyphosate allows farmers to plant crops relatively quickly and can also limit operational use of heavy machines. In fact, accidents involved with the use of heavy machinery have a prevalent cause of severe injury in agriculture. Glyphosate herbicides have greatly reduced the operation of many of the heavy machines and thus decreased the total number of accidents in the field.[4]

Despite the many benefits of Glyphosate regarding yield and weed control, there are also various number of negative consequences that comes with the use of glyphosate. One of the major downsides is the toxicity involved with glyphosate. Many herbicide products used containing glyphosate also carry what is known, as surfactants are compounds that lower the tension between two liquids. As noted by data in New Zealand identified Roundup to contain 18% Surfactant which allows the glyphosate chemical to penetrate the surface of the plant. With different chemicals mixed in with glyphosate, there are some adverse effects if one is exposed.[5] There are many studies that show that even minute exposure can cause some adverse effects. For instance, farmers that touched their eyes after using glyphosate experienced irritation in the eye[6]. Inhalation of glyphosate can cause different oral problems, such as irritation to the throat. Exposure of glyphosate to the skin can also cause eczema in the specific exposed area. Negative consequences of glyphosate have also been detected on animals that have been tested to see for adverse effects. Tests on rats revealed that inhalation of products containing glyphosate caused reduced respiratory ability and weight loss.[7] Long-term effects also showed development of tumors in the liver and thyroid and the pancreas. A study on rats done in 2010 found that when rats, prior to going through puberty were given Roundup (transorb) once everyday for 30 days showed that they had a decreased amount of testosterone production.[8]

Glyphosate also has several environmental effects, specifically on both land and aquatic environments, on a larger scale, can affect entire ecosystems. When herbicides leaked into bodies of water, lethal effects to different aquatic organisms such as tadpoles and fish. In addition, when applied, glyphosate kills plants in any area where it is distributed and plants also in their surrounding areas[9]. The death of these living organisms, both on land and in water can have prodigious effects on a broader scale. For example, killing unwanted plants can have drastic effects affecting first insects, then birds and even small mammals. This interference of a food chain can lead to the destruction of entire ecosystems. Another major factor that needs to be taken into account is that due to subsequent use of Roundup in agriculture, weed resistance is a growing problem in the United States.[10] Because of this, farmers use a greater concentration of Roundup to dispose of unwanted weeds and this in terms further adversely affects plants that are surrounding the weeds, leading to a holistic effect on the ecosystem. The following concern surfaces as glyphosate resistant weeds can transfer that gene (resistant to glyphosate) to other plants/weeds and in turn, development of new herbicides with additional chemicals that potentially may have more adverse effects have to be introduced. This arms race can have extremely negative effects to the ecosystem and to the environment as a whole.
References:

1) O’Keeffe M G, “The control of Agropyron repens and broad-leaved weeds pre-harvest of wheat and barley with the isopropylamine salt of glyphosate.” Proceedings of British Crop Protection Conference – Weeds, 1, 53-60 (1980).

2) Alibhai MF, Stallings WC. “Closing down on glyphosate inhibition—with a new structure for drug discovery”. Proc. Natl. Acad. Sci. U.S.A. 98 (6): 2944-6. Bibcode:2011PNAS…98.2944A. doi:10.1073/pnas.061025898.JSTOR 3055165. PMC 3334.PMID 11248008 (March 2001).

3) Steinrücken HC, Amrhein N “The herbicide glyphosate is a potent inhibitor of 5-enolpyruvyl-shikimic acid-3-phosphate synthase”.Biochem. Biophys. Res. Commun. 94 (4): 1207–12. doi:10.1016/0006-291X(80)90547-1.PMID 7396959 (June 1980).

4) Franz JE, “N-phosphonomethyl-glycine phytotoxicant compositions”, issued 1974-03-26, assigned to Monsanto Company

5) Causes and circumstances of accidents in the EU (2008). European Commission Directorate-General for Employment, Social Affairs and Equal Opportunities, F4 unit. epp.eurostat.ec.europa.eu/portal/page/portal/health/documents/phase_3_causes_circumstances.pdf

6) Gary L. Diamond and Patrick R. Durking, under contract from the United States

Department of Agriculture. “Effects of Surfactants on the Toxicity of Glyphosate, with Specific Reference to RODEA” (February 6,1997

7) Bradberry SM, Proudfoot AT, Vale JA “Glyphosate poisoning”. Toxicol Rev 23 (3): 159-67. Doi: 10.2165/00139709-200423030-00003. PMID 15862083

8)  Temple WA and Smith NA, “Glyphosate herbicide poisoning experience in New Zealand”, New Zealand Medical Journal, 105: 173-174, (1992).

9) Romano RM, Romano MA, Bernardi MM, Furtado PV, Oliveira CA. “Prepubertal exposure to commercial formulation of the herbicide glyphosate alters testosterone levels and testicular morphology”. Arch. Toxicol.84 (4): 309-17. Doi:10.1007/s00204-009-0494-z. PMID 20012598 (April 2010).

10) Giesy JP, Dobson S, Solomon KR. “Ecotoxicological Risk Assessment for Roundup Herbicide”. Reviews of Environemntal Contamination and Toxicology. Reviews of Environmental Contamination and Toxicology (2000)

11) Graves L. “Roundup: Birth Defects Cause by World’s Top Selling Weedkiller, Scientists Say”. Huffington Post (24 June 2011).