Science in Society Archive

Glyphosate Toxic to Mouth Cells & Damages DNA, Roundup Much Worse

Further evidence of genotoxic and cytotoxic effects – a prelude to cancer, birth defects and reproductive problems Dr Eva Sirinathsinghji

New research finds that glyphosate causes cell and DNA damage to epithelial cells derived from the inside of the mouth and throat [1]. It raises concerns over the safety of inhaling glyphosate, one of the most common ways in which people are exposed to the herbicide.

Siegfried Knasmueller and his colleagues the Medical University of Vienna, Austria, found that Monsanto’s formulated version of glyphosate called Roundup Ultra Max caused cellular damage and DNA damage including chromosomal abnormalities and ultimately killed the cells at higher concentrations. Importantly, DNA damage occurred at concentrations below those required to induce cell damage, suggesting that the DNA damage was caused directly by glyphosate instead of being an indirect result of cell toxicity.

These are not the first findings of glyphosate-based herbicides’ cytotoxic and genotoxic effects. Numerous independent research teams have been documenting the hazards of glyphosate exposure over the last few years with in vivo, in vitro and clinical studies.

DNA damage was observed in blood samples from exposed residents in Argentina and Ecuador [2, 3]. Lab mice were found to harbour chromosomal and DNA damage in bone marrow, liver and kidney cells as well as lymphoid cells [4]. Similar effects were found in non-mammalian species, including sea urchins [5], goldfish [6, 7], eels [8], tilapia fish [9] as well as the fruitfly [10]. These experiments show that glyphosate herbicides are dangerous for humans and many other animals. Glyphosate is highly soluble in water, so impacts on aquatic wildlife may be of particular concern, especially following the recent report on the presence of glyphosate in rain water, groundwater, rivers and air [11, 12]. Its extreme toxic effects on amphibians such as frogs has already been shown (see [13] Roundup Kills Frogs, SiS 26). Cell damage has been documented in many cell types including those derived from the rat testis (see [14] Glyphosate Kills Rat Testes Cells, SiS 54), human placenta, umbilical cord, and embryo (see [15] Death by Multiple Poisoning, Glyphosate and Roundup, SiS 42), rat and carp neurones [16, 17], and liver [18, 19].  

Multiple tests all show cellular damage in response to Roundup  

To reflect occupational exposure, human buccal epithelial cells were exposed to glyphosate and Roundup for 20 minutes only at concentrations from 10 mg/L to 200 mg/L.  The Roundup formulation used for the experiments contains 450 g/L of glyphosate and should be diluted according to the manufacturer’s instructions to 1–3 % before use (final concentration 4 500–13 500 mg/l). The researchers found some significant effects with 10-20 mg/l, equivalent to a 225–1 350-fold dilution of the spraying solution.

Cell damage was assessed by the release of the membrane-bound enzyme lactose dehydrogenase into the culture medium. The integrity and viability of cells was indicated by their staining with neutral red as only healthy cells retain the dye.  Mitochondrial function was assessed by measuring the activity of the enzyme mitochondrial dehydrogenase with the substrate XXT that gives a yellow colour product.  And cell proliferation was measured by the total protein content of the cell cultures.

The results showed that the cells were much more sensitive to the Roundup formulation than glyphosate. With Roundup, a significant effect was seen at a dose level of 40 mg/L with the XXT assay, while a clear increase of the lactose dehydrogenase levels was seen already with 10 mg/L. The cell proliferation and the neutral red assays were less responsive, with significant effects detected at 80 and 100 mg/L, respectively (still well below agricultural use levels). All effects were dose-dependent.

With glyphosate, no significant effects were seen in 3 of the 4 assays, with only lactose dehydrogenase showing significant effects at over 80 mg/l. 

Multiple tests show Roundup causes DNA damage

DNA damage was analysed by two methods. The first is the Single Cell Gel Electrophoresis (SCGE) assay, which reveals single or double-stranded breaks in DNA. The second is a special comprehensive assay of chromosome instability that picks up many DNA aberrations including chromosome breakage, DNA misrepair, chromosome loss,  as well as cell death by either necrosis (cell death that results from external stressors such as toxins), apoptosis (programmed cell-death) and cell growth. Different nuclear anomalies were measured including micronuclei, a biomarker of chromosomal damage, breakage or loss; nuclear buds, a biomarker of elimination of amplified DNA and/or DNA repair complexes; and nucleoplasmic bridges reflecting the formation of dicentric chromosomes (chromosomes with 2 instead of 1 centromere) , a marker of DNA misrepair and/or end-fusions of the chromosomes.

Significant effects on DNA integrity as assessed by the SCGE assay were seen at 20 mg/l of both Roundup and glyphosate, increasing in a dose-dependent manner.

Exposure of the cells for 20 minutes also led to a significant and dose-dependent increase of nuclear anomalies including increases in the total number of micronuclei beginning at 10 mg/L of Roundup, and 15 mg/L of glyphosate. The number of nuclear buds increased with exposure concentrations, starting at 10 mg/L with both glyphosate and Roundup. In the case of the nucleoplasmic bridges, the only significant effect was obtained with the highest dose of Roundup used (20 mg/L). Apoptotic cells were observed following 20mg/L of Roundup but not glyphosate, while necrosis occurred in response to 20mg/L of both Roundup and glyphosate.

In summary, Roundup was cytotoxic at concentrations as low as 20 mg/L, while its active ingredient was not generally cytotoxic to buccal epithelial cells. Both glyphosate and Roundup elicited genotoxic effects at concentrations below the level required to induce cell damage. The different effects between the active ingredient and its commercial formulation is consistent with previous work, including experiments done on testicular, placental, embryonic and umbilical cord cells (see above).  These results may explain some of the ailments observed in people who work with this herbicide and adds yet more weight to an outright ban of the herbicide [20] Ban Glyphosate Herbicides Now, SiS 43).

Article first published 28/03/12


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There are 10 comments on this article so far. Add your comment above.

Nancy Oden Comment left 29th March 2012 14:02:09
Bit techy for sending out to masses....may we have a "regular people" version listing effects on people and their children for wider distributiion? Thanks.

Kevin Folta Comment left 31st March 2012 19:07:49
It is peer reviewed. They looked at culturing a buccal (cheek) metastatic cell line with roundup and glyphosate. I will read an report.

Todd Millions Comment left 8th April 2012 16:04:40
It is worth belabouring that-contrary too the still official,"holy BS"being repeated by health and ag ministers and officials(like hillaries human rights scripts run up in tel aviv and chanted by bbc/cbc ministries of truth),The breakdown rates of glyphosates-'within 1 meter of soil perculation'is a lie.It was 4 years from danish approval to it being detected in 60-70 meter well water suppling copenhagen.I suspect covering this up was how(as a reward) we got the current nato pinhead de charge.

MaryKelly Sutton MD Comment left 10th April 2012 18:06:35
I would like to get published articles on GMO effects on humans to ask my continuing medical education program to include them in the database! Anyone who can send things my way, much appreciated.

Solange De Metri Comment left 11th March 2013 16:04:38
Round Up Max is a different formulation than regular round up. It is used to prevent seed germination as well as kill existing weeds. It is a soil sterilant. I am not saying it isn't dangerous but you shouldn't be drinking it either.

Jim S. Smith Comment left 18th April 2013 16:04:53
What I would like to know, in addition to what I have already learned here, is HOW LONG does Glyphosate and its analogs remain in the soils? I have heard too many a "salesmen's" commentary about "how bio-degradable" this Glyphosate is (like, in someone's brand of: "Weed-and-Feed" lawn-care products). Glyphosate does NOT appear nor occur in Nature! It is purely a synthetic chemical compound. Therefore, like most synthetic compounds, I would strongly suspect that it also remains in the environment for longer periods of time than is being claimed. My concern behind the question of Glyphosate's possible long-term "chemical-stability" is that this could mean that treated soils are building up high levels and concentrations of the chemical, Glyphosate. I have visually-seen areas that were treated for several years with various Glyphosate-containing products. Now, many of those particular areas will not grow ANYTHING in them! This almost reminds of the same kind of effect that using too much winter "ice-melt" is having on our city's trees. Many of them are showing visible signs of "salt-poisoning" near our sidewalks and driveways downtown. I have also watched, as a young child, as a very large, healthy willow tree died within a week after "2-4 D" herbicide was "lightly-"sprayed to control lawn weeds! This Glyphosate is also an indiscriminate killer of plant (and animal?) life, and is supposed to be far more powerful than "2-4 D" and "2-4-6 T" herbicides. Does anyone have an estimate on how long it takes Glyphosate to breakdown in the soils, or if it ever really "decomposes" at all??? I would really like to know! - Jim S.

field lily Comment left 17th July 2013 02:02:35
Ok it is a bit techy, but it simply boils down to this, "roundup by any other name still just as deadly, no matter how safe they say it is"

Melanie Comment left 12th February 2014 21:09:50
Well done on this valuable work. If people could only realise how damaging these chemicals are. Rachel Carson gave us the warnings years ago in her book Silent Spring. I have experienced and seen too much damage from harmful chemicals and pesticides in my life time through living in the country surrounded by heavily sprayed agriculture. Much more research is needed at this end and into organic sustainable earth friendly non GM methods. Thank you Yours faithfully Melanie

Black Orchid Comment left 29th October 2014 23:11:01
Military Industrial Complex. Poisons. Agent Orange. Birth Defects. Death. Who chooses a global mass poisoner to be their only food source? Revolving door employment between the manufacturer, the federal legislating government and science. Conflict of interest in class action suits, major bias in crop copyright suites and the Supreme Court. Patented crops contaminating normal crops in country's where they are banned. Who needs a patent, if all crops are owned as if by god? This makes it a religious issue as well. Polluted ground water world wide and pest resistance should be reason enough to end this Machiavellian murderous scheme and fraud.

James Barber Comment left 31st December 2014 08:08:04
The studies show that if you put enough material in vitro you will cause problems. With the premise being that you test with respect to industrial use it would be unethical to assert that consumption at much lower dosages would cause any damage in vivo. Conclusive that more research needs to be done, at lower dosages, as well bio accumulation effects studied.