Is The Herbicide Glyphosate Killing Our Earthworms — And Why That Would Matter

Could the herbicide glyphosate, commonly found in Monsanto’s RoundUp, be killing our earthworms? A study published in the scientific journal Water, Air & Soil Pollution last quarter found that when researchers examined the toxicity of pesticides and herbicides, their effects on earthworms and other species in the soil are not adequately examined.

Authors of the study, which focused on the “sublethal effects” of glyphosate on earthworms, was co-authored by Marina Santadino, of the National University of General Sarmiento in Argentina, Carlos Coviella, an agronomic engineer from National University of Luján, and Fernando Momo, also of the National University of General Sarmiento.

The researchers performed an experiment that studied the effects of gylphosate on the earthworm Eisenia fetida. In the study, the adult earthworms were separated into three groups. The first group of earthworms was exposed to no gylphosate. The second group of earthworms was exposed to a typical dose of gylphosate that is advised for perennial weeds. The third group of earthworms were exposed to a double dose of glyphosate.

Each week, each group of earthworms was examined. Two samples were gathered from each group. The samples were analyzed for the number of “adults, individual weight, number of cocoons, and presence and number of young earthworms,” according to the authors who performed a matrix analysis of the data. The results showed that the earthworms that were not exposed to glyphosate had a positive population growth rate. Both of the glyphosate-exposed groups had a negative growth rate.

The researchers said that their results indicate that while glyphosate based herbicides, like RoundUp, are not intended to limit the population of earthworms, with glyphosate application in lawn-maintenance and farming, earthworms are at risk of local extinction.

Earlier this year, according to Nature, glyphosate was also shown to affect the physiology of earthworms. This shouldn’t be that shocking because a study from four years ago published in the journal Bulletin of Environmental Contamination and Toxicology found very disturbing effects on earthworms from the chemicals glyphosate and 2,4-D.

“For 2,4-D, 100% mortality was observed in soil treated with 500 and 1,000 mg/kg. At 14 days, 30%-40% mortality levels were observed in all other concentrations. No cocoons or juveniles were found in soil treated with either herbicide. Glyphosate and 2,4-D demonstrated severe effects on the development and reproduction of Eisenia foetida in laboratory tests in the range of test concentrations.”

Alternately, other research indicates that we don’t need to worry about the earthworm population. Inquisitr previously reported that some scientists are actually worried that earthworm populations may become too great — thanks to climate change.

Whether we need to worry about localized extinction of earthworms, or a global overpopulation of the species, the researchers’ latest findings bring up a critical issue: According to the researchers, other non-targeted species may be similarly affected by glyphosate application.

“Non-target organisms can be at risk of local extinction due to agrochemicals chronic sublethal effects, which are not consistently taken into account in toxicity and risk assessment studies.”

Manufacturers of glyphosate herbicides, like Monsanto, say it’s perfectly safe.

Organic farming proponents conversely point out that glyphosate has already been found in human breast milk samples and wonder if humans could be among the non-target organisms at risk from glyphosate use, though officials deny that glyphosate in breast milk is a cause for concern.

[Photo by Holger Casselmann]