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).
