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”.
OUR COMMENT
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.
Background:
[1] GM MAIZE IS NOTSAFE TO EAT - October 2012
[2]
TORCHING THE SCIENCE - December 2013
SOURCES:
- 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
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