Glyphosate and AMPA in the air

May 2018

GM crops are still hanging on to their 'environmentally-friendly' image.

Resistance to glyphosate-based herbicides is a feature of most GM crops. This GM trait enables soil-preserving no-till farming, and provides easy weed control with a single chemical reputed to be toxic only to weeds and to disappear readily from the environment. All this, plus glyphosate's early 'safe-as-salt' tag for humans [1] provided little incentive for scientific study of side-effects of the herbicide during the past decades of increasing use.

However, things are changing since the International Agency for Research on Cancer came to the conclusion that glyphosate is 'probably carcinogenic to humans' [2]. Questions are gradually surfacing about where glyphosate actually goes when it 'disappears' from the environment.

The emerging answers don't paint a comforting picture.

Argentinian scientists took a close look at what actually happens to glyphosate after its application in the field.

A large proportion of the herbicide sprayed before or during crop production ends up in the surface layer of the soil either directly because it's missed the plants or in the rotting vegetation of the weeds it's killed. There, a large proportion becomes very firmly stuck to the surface of soil particles; some becomes broken down by soil microbes to a derivative 'AMPA'* which is formed more quickly than it can be further degraded so that it accumulates in the soil; some washes away in surface water. In other words, most glyphosate doesn't actually 'disappear', it just gets stuck in the soil in different forms or it goes somewhere else.

*Aminoethylphosphonic acid, now suspected to be at least as toxic as glyphosate.

What happens next, especially in arid and semi-arid areas such as are found in Argentina, is that the surface of bare soil becomes eroded by the wind. Large particles, complete with their glyphosate and AMPA load, are too heavy to be carried far by the wind: they soon drop back onto the soil surface where they smash up the soil they land on to create ever smaller fragments.

Small particles, which have a relatively bigger surface area, attract a relatively greater load of glyphosate and AMPA. These lighter particles can be carried a very long way by the wind. Indeed, although the amount of glyphosate and AMPA in air-borne dust particles found over a 'no-till' landscape was larger than elsewhere, measurable amounts were recorded in unexpected locations. One such location was a crop-growing area of conventional plants and conventional tillage where glyphosate use had been minimal. Another such location was in an area of pasture mainly surrounded by forest where glyphosate had never been used.

Compared with the original soil, the glyphosate/AMPA concentration in wind-blown material was greater by sixty- and three-fold respectively, increasing with height above the ground. The largest amounts of herbicide contamination was found at 150cm above the ground.

It seems glyphosate and AMPA in the soil can hitch a ride on the wind and travel a very long distance at a height where they are most likely to be breathed in by human beings.


Modern glyphosate sprays wth additives to reduce drift or to make the herbicide stick better to the plants might be ending up in larger amounts in the soil, and so in the dust emerging from the soil, and so in the humans souls breathing in the dust. The surprise finding of glyphosate in the urine of 93% of a small sample of women in Indiana [3] suggests a continuous and ubiquitous dosage of the population with this herbicide. Breathing glyphosate in as it hangs in the air would fit the picture.

The concern in the case of the Indiana study wasn't cancer but cognitive damage and other health effects in their children.

For the sake of future generations, we need to get agri-chemicals out of our food and fields and definitely out of our air.


[1] GLYPHOSATE: SAFE AS SALT? (Doc) - GMFS Archive, February 2009

  • Virginia c. Aparicio, et al., 2018, Glyphosate and AMPA concentrations in wind-blown material under field conditions, Land Degradation and Development
  • S. Parvez, et al., 2018, Glyphosate exposure in pregnancy and shortened gestational length: a prospective Indiana birth cohort study, Environmental Health

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