|Gilles-Eric Séralini. CC photo by Alberto Novl on Flickr|
He has pointed out that the 'proof' of safety of GM crops and their associated herbicide, 'Roundup' has been manipulated to skirt evidence of harm: key test materials have been excluded, exposure times have been curtailed, and the parameters measured have been limitated. When differences have been too obvious to ignore, they have been dismissed as “not biologically meaningful” (Séralini, republished). His suggestions that there were signs of endocrine disruption were met with an orchestrated attempt to discredit him [1,2].
However, Prof Séralini is a scientist, and has no time for PR stunts. His reaction to his critics has been to do the science, to set about carrying out the experiments which should have been done at the dawn of GM.
Unfortunately for the biotech industry, each experiment published is more damning than the one before.
The latest research to emerge from Séralini's team investigated the implications to farm-workers of exposure to Roundup. While fields are being sprayed, farm-workers are known to receive acute doses of chemicals. The effects of Roundup on their health, especially in light of the increased quantity and frequency of applications on GM crops, have not been assessed.
Noting the “ongoing international debate as to the potential reproductive toxicity of glyphosate-based herbicides such as Roundup” coupled to suspicions about endocrine disruption, the French scientists measured a range of markers for reproducive health in rats which had been given the herbicide in their drinking water (at a dose similar to that found in water after agricultural spraying) for eight days.
It was established that no toxic effect resulted from the herbicide exposure: this meant that changes could be attributed to endocrine disruption rather than to secondary effects of toxicity.
A number of disturbing changes were noted. For example:
- Although the usual parameters used to check male reproductive effects (testis weight, and sperm concentration, viability and motility) were normal, a closer look at the sperm cells revealed increased abnormal morphology and failure of the nuclei to mature. Both of these reduce fertility
- All tissues examined had increased production of the enzyme 'aromatase'. This enzyme drives the production of oestrogen hormone. Oestrogen is one vital and powerful part of a huge and finely balanced complex of active biochemical pathways which work twgether to produce healthy, fertile sperm. An across-the-board stepping up of oestrogen production could be a response to some blockage elsewhere in the sequence, and is likely to result in an unhealthy imbalance in the whole sperm-production system.
- There were signs that the vital blood-testis barrier had been compromised. This barrier protects developing sperm from toxins and from the body's own immune system. It is a fluid barrier which systematically degenerates when the sperm cells are ready to move out, while at the same time reforming behind them to protect the still-developing cells. The barrier is the product of an ever-changing network of structural and controlling elements working together. Malfunction of even one of these elements could expose the sperm cells to harm.
The authors concluded that acute exposure to glyphosate-based herbicides as increasingly experienced by farm-workers causes changes in reproductive function, with particular reference to oestrogen balance. They also hypothesised that “the repetition of successive exposures (to glyphosate-based herbicides at sub-agricultural doses could alter the mammalian reproductive system over the long-term”.
These findings do not bode well for farm-workers, bystanders, consumers of GM herbicide-tolerant foods and feed, nor mammalian wild-life.
The need to avoid GM food and animals fed GM feed is becoming ever more urgent.
Consumer rejection is a block no one can get round for ever: make sure it doesn't move.
 GM MAIZE IS NOTSAFE TO EAT - October 2012
 TORCHING THE SCIENCE - December 2013
- Estelle Cassault-Meyer et al., 2014, An acute exposure to glyphosate-based herbicide alters aromatase levels in testis and sperm nuclear quality, Environmental Toxicology and Pharmacology 38
- C.Y. Cheng and D.D. Mruk, 2012, The blood-testis barrier and its implications for male contraception, Pharmacology Review 64(1) January
- Roundup damages sperm - new study, GM Watch, 13.06.14
- Gilles-Eric Séralini et al., 2014, Republished study: long-term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize, Environmental Sciences Europe 26