Renewable Farming

Glyphosate based herbicide formulations: toxic at “safe” regulatory levels?

A new study accepted for publication in the scientific journal Food and Chemical Toxicity examines a wide range of research on glyphosate in conjunction with its chemical adjuvants, which are used to enhance effectiveness in killing weeds. 

Glyphosate is one of the most-studied compounds known. But it has almost always been used alone in toxicology experiments, not with the array of surfactants added to the blend for application as a herbicide. Labels of herbicides containing glyphosate typically do not specify the surfactants and other adjuvants added as “intert ingredients” to make glyphosate more effective as a chelator/weedkiller.

In recent years, a wider array of health studies around the world have examined the toxic impact of Roundup and other such formulations as they’re actually used in the field, not as glyphosate occurs alone in the lab. 

You can download the entire PDF document at this link. The complete citation is:  Mesnage, R, Defarge, N, Spiroux de Vendômois, J, Séralini, G.E, Potential toxic effects of glyphosate and its commercial formulations below regulatory limits, Food and Chemical Toxicology  (2015), doi: 10.1016/j.fct.2015.08.012.

Here’s the summary of the detailed international analysis, a direct quote from the paper: 

“Taken together, studies performed below regulatory limits and relevant for environmental exposures, at best indicate the potential of glyphosate – and more importantly, the commercial formulations containing glyphosate – to cause endocrine related harmful effects at low levels over long periods.

“At this stage, it is not clear whether this is because of glyphosate, a formulation constituent, or the two together. Drawing any firm conclusion from these studies is not possible at this stage and further work is needed to determine the safety or risk of the herbicide alone or in formulations, especially at levels below the regulatory safe limits and over longer durations.

“However, glyphosate is never used alone in vivo, and glyphosate based herbicide formulations have been proven toxic on several cellular and in vivo endpoints below regulatory limits in many studies. This was not the case for glyphosate alone, according to regulatory agencies. With appropriate study design it should be possible to segregate the effects due to glyphosate alone, constituent(s) of the formulation, or the two together. The current evidence presented above raises concerns and indicates the need for further studies. We call for a public, independent, transparent, multidisciplinary assessment of Roundup and other glyphosate based herbicide formulations.”

One adjuvant in particular has been widely used in glyphosate formulations: POEA (polyethoxylated tallow amine).  You can read an excellent summary about POEA and other surfactant/adjuvants in this report by Christina Sarich on the Natural Society website.

Other summaries of field toxicity were appearing more than five years ago, such as this news report in Environmental Health News by Crystal Gammon in 2009.

Despite all the accumulation of evidence on endocrine disruption and other health threats of glyphosate weedkiller blends, chemical companies and the farm media mostly ignore the troublesome data. Instead, the ag media clamor is for assuring our international customers and consumers at home that U.S. crops are safe — repeating the unfounded claim that not a single case of health problems has been shown from GMOS and the herbicides linked with them.