A new study shows that the market-leading Roundup herbicide kills soil microbiota at concentrations 50 times lower than used in agriculture, writes Claire Robinson. The findings raise serious new concerns about the environmental impacts of glyphosate herbicides.
Roundup is toxic to a soil fungus at doses well below recommended agricultural dilutions, according to a new scientific study published in the journal Environmental Science and Pollution Research.
The study was conducted on a soil filamentous fungus, Aspergillus nidulans *, which the researchers used as a marker of the health of agricultural soils.
The dose that caused 50% mortality of fungus (LD50) corresponded to a dilution 100 times less than that used in agriculture - an environmentally relevant dose. At a dose 50 times lower than the agricultural application rate, mortality climbed to 100%.
The commercial formulation of Roundup proved to be much more toxic than glyphosate alone, highlighting once again that the additives are not inert and must be taken into account in the evaluation process.
At the LD50 and lower doses, the effects of Roundup were multiple and included impaired growth and cell disturbances, especially at the level of energy and respiratory metabolism. The new analysis highlighted a new mode of action of Roundup on energy metabolism different from that observed previously in animal cells.
Microorganisms crucial to healthy soil
Microorganisms such as fungi are crucial to healthy soil. Since Roundup is the most widely used herbicide in the world, soil microorganisms in many areas will be exposed to it.
The new study was carried out as part of a participatory research project called Institutions-Citizens Partnership for Research and Innovation (PICRI). It was conducted by a team of researchers led by Christian Vélot, a lecturer and researcher in molecular genetics at the University Paris-Sud, France.
The team studied the effects of a commercial formulation of Roundup called GT Plus, containing 450 mg/L of glyphosate (the stated active ingredient).