glyphosate


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herbicide

herbicide (hrˈbəsīdˌ), chemical compound that kills plants or inhibits their normal growth. A herbicide in a particular formulation and application can be described as selective or nonselective. In agriculture, selective herbicides are often used instead of tillage, or in combination with tillage and other agronomic practices, to control weeds without damaging crops. For these no-till or low-till systems, scientists have used biotechnology to develop crop varieties with increased tolerance for herbicides. Nonselective herbicides (e.g., paraquat) toxic to all plants, are used where complete control of plant growth is required.

Contact herbicides kill only the parts of the plant they touch; systemic herbicides are absorbed by foliage or roots and translocated to other parts of the plant. Preemergence herbicides, mixed into the soil, will kill germinating seeds and small seedlings. Postemergence herbicides either hinder photosynthesis or inhibit growth.

Early chemical herbicides were inorganic compounds. Herbicides such as ashes, common salts, and bittern have been used in agriculture since ancient times. Observation in 1896 that Bordeaux mixture, a fungicide, also provided control of certain weeds, led to the use of copper sulfate as a selective weed killer to control charlock (wild mustard) in cereals. By 1900, solutions of sulfuric acid, iron sulfate, copper nitrate, and ammonium and potassium salts were known to act as selective herbicides; soon thereafter sodium arsenite solutions became the standard herbicides, and they were used in large quantities until about 1960. Other inorganic herbicides include ammonium sulfamate, carbon bisulfide, sodium chlorate, sulfuric acid solutions, and formulations containing borate.

Organic herbicides began to be produced in earnest with dinitrophenol compounds in 1932. A breakthrough occurred in the 1940s with 2,4-D (2,4-dichlorophenoxyacetic acid), a compound similar to plant hormones, which is a highly selective systemic herbicide when used in very small quantities. 2,4-D was quickly adopted to control broad-leaved weeds in corn, sorghum, small grains, and grass pastures, as well as in lawns and other ornamental turf. The phenoxyaliphatic acids and their derivatives, another major group of organic herbicides, succeeded because of their selectivity and ease of translocation. Other groups of organic herbicides include organic arsenicals, substituted amides and ureas, nitrogen heterocyclic acids, phenol derivatives, triazines, and sulfonylureas.

In the 1960s and 1970s, a combination of 2,4-D and 2,4,5-T was widely used in Vietnam as a defoliant under the name Agent Orange. As a result of questions concerning the possible health effects of the use of Agent Orange, heightened awareness of possible ecological and health dangers attributable to herbicides has resulted in reevaluation of many compounds and has called indiscriminate use into question. Use of the dioxin-containing 2,4,5-T was prohibited in the United States in 1984. In 1975, Mexico, at the urging of the United States government, began spraying fields of marijuana with paraquat, which both eliminated the crop and raised fears of toxic side effects in marijuana users.

Glyphosate, a compound first identified as a herbicide in 1970 and sold beginning in the 1970s (initially only under the tradename Roundup), has been widely used as a broad-spectrum weedkiller because of its apparent relatively low toxicity and tendency to degrade relatively quickly in the environment. Beginning in the 1990s, the use of crop strains that were resistant to its herbicidal effects contributed to the herbicide's much more widespread use and led to the development of so-called superweeds, which have resistance to glyphosate.

See also pesticide.

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glyphosate

[′glif·ə‚sāt]
(organic chemistry)
C3H8NO5P A white solid with a melting point of 200°C; slight solubility in water; used as a herbicide in postharvest treatment of crops.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
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"Such a ban would ignore the overwhelming scientific assessments of competent authorities around the world that have determined for more than 40 years that glyphosate can be used safely," Bayer said.
He asked: "Could you tell me if we are working towards doing away with glyphosate?" Gordon McNeil, the council's director of Environment and Infrastructure, said: "We have undertaken a trial of a couple of other products.
The EPA says its research shows the chemical poses no risks to public health and won't approve warning labels for glyphosate products, the AP reported.
Juries in several lower courts granted plaintiffs massive damages awards, although they were later reduced by judges and Bayer vowed to appeal -- saying the weight of scientific evidence is against glyphosate causing cancer when used appropriately.
"But most people in the UK will never be exposed to high levels of glyphosate and there's no good evidence that there's an increased risk for people exposed at low levels."
https://www.scotsman.com/subscriptions/While that same report acknowledged that in 2017 the European Chemicals Agency and the European Food Safety Authority both concluded that there is no evidence to link glyphosate to cancer in humans, an increasing number of public agencies have concluded that it is not worth the risk.
PUBLIC HEALTHSecondly, independent science-based regulatory agencies around the world have comprehensively evaluated glyphosate-based herbicides and found them safe to use in accordance with label directions.In its Glyphosate Proposed Interim Decision released in April, the US Environmental Protection Agency said "there are no risks to public health when glyphosate is used in accordance with its current label instructions and that glyphosate is not a carcinogen".
A child would only need to eat a single 60 gram serving of food with a glyphosate level of 160 ppb to reach the maximum dose considered safe by EWG," said (https://www.ewg.org/release/new-round-ewg-tests-finds-more-children-s-cereals-tainted-monsanto-s-cancer-causing) the statement.
"We need better guidelines for glyphosate use, especially regarding bee exposure because, right now, the guidelines assume bees are not harmed by the herbicide.
Bayer, which acquired Roundup maker Monsanto for $63 billion last year, denies the allegations, saying decades of studies and regulatory approvals have shown glyphosate and Roundup to be safe for human use.
Environmental Protection Agency's interim registration review decision released just last month, the consensus among leading health regulators worldwide that glyphosate-based products can be used safely and that glyphosate is not carcinogenic, and the 40 years of extensive scientific research on which their favorable conclusions are based.