New types of safety studies needed that look at effects of low doses

Fourteen scientists have published a consensus statement expressing concern over the health risks of exposure to glyphosate-based herbicides such as Roundup.

The scientists say that the supposed safe limits for glyphosate set by regulators are based on outdated science. They recommend that new types of safety studies are conducted that are sensitive enough to detect the effects of low doses that people could realistically be exposed to.

The new paper appears in the peer-reviewed journal Environmental Health. The authors include prominent experts in endocrine (hormone)-disrupting effects of chemicals at low, environmentally realistic doses.

Co-author of the new review, London-based molecular biologist Dr Michael Antoniou said, “The findings of this review are very worrying as they indicate that regulatory agencies are basing their evaluation of glyphosate’s safety on outdated science. Therefore until regulators reappraise glyphosate’s safety to include possible toxicity from low-dose consumption, people should take precautions to avoid exposure to this weedkiller through both food and environment.”

Other main points in the paper include:

(1) Glyphosate herbicides are the most heavily applied type of herbicide in the world and usage continues to rise
2) Worldwide, glyphosate herbicides often contaminate drinking water sources, rain, and air, especially in agricultural regions
(3) Glyphosate persists in water and soil longer than previously recognized
(4) Glyphosate and its metabolites are widely present in the global supply of GM glyphosate-tolerant soybeans
(5) Human exposures to glyphosate herbicides are rising
(6) Glyphosate is now authoritatively classified as a probable human carcinogen.

The scientists recommend new investments in epidemiological studies, biomonitoring, and toxicology studies that draw on the principles of endocrinology to determine whether the effects of glyphosate-based herbicides are due to endocrine-disrupting activities.

Currently studies performed by industry to test the safety of chemicals such as glyphosate use high, unrealistic doses that fail to reflect real-world low-dose risks and fail to detect endocrine-disrupting effects. Yet these can be serious – endocrine disruption is a suspected factor in the development of some cancers, birth defects, and developmental problems in children.

Neither the US nor the European authorities have finalized tests for endocrine-disrupting effects of pesticides and other chemicals. The authors point out in their paper that the US EPA was mandated 17 years ago to come up with a battery of tests capable of detecting such low-dose effects, but is still years away from doing so.

Another problem with regulatory safety tests is that they are performed on the isolated presumed active ingredient of the pesticide – in the case of glyphosate-based herbicides, that’s glyphosate – even though the added ingredients in the commercial formulations as sold and used often mean that the complete formulation is much more toxic than the presumed active ingredient alone.

The authors of the new paper suggest that common commercial formulations of pesticides should be prioritized for inclusion in government-led toxicology testing programmes such as the US National Toxicology Program, as well as for biomonitoring as conducted by the US Centers for Disease Control and Prevention.


Citation: Myers J P et al (2016). Concerns over use of glyphosate-based herbicides and risks associated with exposures: a consensus statement. Environmental Health 15(19). DOI 10.1186/s12940-016-0117-0. Open access: http://ehjournal.biomedcentral.com/articles/10.1186/s12940-016-0117-0