Roundup's conceptual gaps

October 2015


As one of its very limited number of GM success stories, the biotech industry has moved whole-sale into herbicide-tolerant crops. Most successful of these has been 'Roundup Ready' staple crops with a novel gene allowing them to survive and accumulate glyphosate, active ingredient of Roundup.

However, it's becoming clear that underpinning Roundup Ready crops, is a number of conceptual aberrations.

Scientists who, by training should know better, regularly confuse 'glyphosate' chemical herbicide with the formulation (such as Roundup) in which it's actually used. Formulated herbicides contain more added ingredients to aid killing than they do glyphosate, and even on their own these can be much more toxic than the herbicide [1]. The consequences of this conceptual gap is that only chemical glyphosate, which is never used in practice, has ever been subject to safety testing and regulation.

Then, there's the fixation on the classic model of the toxic reaction. This limitation creates a knowledge gap in which danger lurks.

A key feature of a toxin is that the more exposure you get, the more you're harmed by it. At some identifiable (high) level of exposure you will die. At another identifiable (low) level you won't be affected at all. And, although there will always be some natural variation, no one's going to spoil the picture by being hypersensitive or stubbornly resistant.

The model works well for acute exposure to pure substances which elicit visible tissue damage.

Conceptual gaps emerge in this neat scheme when you factor in such things as low-level chronic exposure, mixtures of substances, people whose bodies are still developing, unrecognised end-points which aren't under observation but which can be fatal, and indirect harmful effects. In other words, in the real-life non-model world, the effects of toxins on our bodies are untidy.

The most glaring examples, now emerging, of science falling through the neat-and-tidy gap, involve toxins which compromise the nervous system [2], or the endocrine system [3]. Neither present as immediate physical changes, but may affect the behaviours necessary for survival, or only the males or only the females of the species, or the next generation, or, in the case of humans (who tend to live much longer than other animals in their environment), the likelihood of expensive and distressing disease in old-age.

Assumptions of identifiable safe levels and decreasing effects with decreasing dose to the point where they vanish altogether are simply invalid for toxins such as endocrine- and gene-disruptors.

Toxins whose effects accumulate quietly and invisibly in the body and in the food chain make their presence known eventually.

Knowingly or unknowingly, scientists can preserve the conceptual gaps by clinging uncritically to outdated, but well-accepted, paradigms and (sadly) by adjusting their experimental conditions and even their data analyses to support the status quo.

It's not difficult, for example, to choose a strain of rodent with a low susceptibility to cancer to 'prove' a substance isn't carcinogenic. Or, to halt an experiment before anything but the most acute problems have time to emerge. Or to define 'health' as 'absence of death'. Or, to look at effects on males only, or on adults only. Or to compare 'test' animals with 'control' animals which have actually been fed toxins [4]. And statistics can be adjusted in all sorts of ways to support all sorts of conclusions.

The authors of a recent published review of the mess which is the scientific and regulatory 'safety' assessment of glyphosate herbicide, concluded that "The current evidence presented above raises concerns and indicates the need for further studies" Specifically, "Neurodevelopmental, reproductive, and transgenerational effects of (glyphosate-based herbicides) must be revisited, since a growing body of knowledge suggests the predominance of endocrine disrupting mechanisms caused by environmentally relevant levels of exposure". They called for "a public, independent, transparent, multidisciplinary assessment of Roundup and other (glyphosate-based herbicides)" [5].

Hear, hear. Tell your MEP to get on with it.


[2] BEES WITH DEMENTIA - September 2015
[5] R. Mesnage, et al., 2015, Potential toxic effects of glyphosate and its commercial formulations below regulatory limits, Food and Chemical Toxicology

No comments:

Post a comment

Thanks for your comment. All comments are moderated before they are published.