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Nov
Secret Inert Ingredient in ‘Bee Safe’ Pesticide Found to Kill Bumblebees
(Beyond Pesticides, November 11, 2021) Evidence is building that so-called ‘inert’ ingredients in pesticide formulations are harming pollinators and undermining regulatory determinations that designate products as ‘bee-safe.’ According to a new study published in Scientific Reports, the fungicide Amistar causes lethal and sublethal effects that can be primarily attributed not to its active ingredient azoxystrobin, but to alcohol ethoxylates, a co-formulant, or inert ingredient intentionally added to a pesticide formulation. While the U.S. Environmental Protection Agency (EPA) utilizes a ‘bee advisory box’ on pesticide labels to indicate danger to pollinators, results of this and previous studies on inert ingredients underline how EPA’s ‘cute little bee icon’ is little more than window dressing for massive regulatory failures and a pollinator crisis that has shown no signs of abating.
Scientists at Royal Holloway University in London, UK began their study with three packaged colonies of Bombus terrestris, a European bumblebee often bred for commercial use in greenhouses throughout the world. In order to suss out differences in toxicity between the various ingredients in the formulated Amistar fungicide, bees were separated into multiple groups. One group acted as a positive control, and was dosed with dimethoate, a pesticide known to be highly toxic to pollinators. Another acted as a negative control and received only water. Researchers exposed separate groups to fully formulated Amistar, and then began to break down exposures based on particular ingredients, with separate bumblebee groups exposed to benzisothiazol, naphthalenesulfonic acid, alcohol ethoxylates, and a mixture of all three, respectively. While the aforementioned ingredients can be found on the material safety data sheet of Amistar sold in the UK, researchers note that because of laws that protect pesticide company trade secrets, other additional co-formulants may be present. Further, Amistar’s formulation in Europe may differ from its formulation in the United States and other countries, despite that fact that chemical company Syngenta/ChemChina is the primary registrant in both locations.
Even with this complexity and the secrecy around pesticide formulations, researchers were able to gather important data on the safety of Amistar’s inert co-formulants. Pollinators were exposed to doses equivalent to amounts used in European regulatory tests, and monitored for five days, beginning four hours after initial exposure.
All positive control bees died, and all negative control bees lived. None died from benzisothiazol, and only one died from naphthalenesulfonic acid exposure. Fully formulated Amistar resulted in 23% mortality, while alcohol ethoxylates, and the mixture of benzisothiazol, naphthalenesulfonic acid, and alcohol ethoxylates resulted in death rates of 30 and 32%. Researchers found that bees that weighed more at the beginning of the study were more likely to survive. That is because alcohol ethoxylates were causing sub-lethal impacts that didn’t necessary kill every exposed bumblebee outright.
Dissection after the experiment determined that alcohol ethoxylates were creating dark brown patches in bumblebee guts. This was leading to a range of observable warning signs. “Whilst 30 percent of bees exposed to the fungicide product died, the other 70 percent were far from healthy; they had damaged guts, were eating about half as much food and were losing weight,” said study coauthor Ed Straw, PhD. “Pesticide regulation typically only looks at whether or not a bee dies, but we found that even bees who survive can be under severe stress.”
With each test, alcohol ethoxylates displayed the same hazards as the fully formulated product, leading researchers to conclude that these substances were the primary danger within this Amistar, a product assessed by regulators as ‘bee safe.’ “To reflect potential sublethal differences caused by co-formulation composition, all formulations could undergo a much more rigorous set of lower tier testing or be automatically entered for higher tier testing,” the study recommends.
Scientists note that their laboratory data were recently confirmed through another experiment conducted under field-realistic conditions. “While the results of lab experiments like this are often questioned, other research done under field-realistic conditions within the PoshBee project show similar results. This combination of results, enabled by this European-wide project, really supports the idea that co-formulants in pesticides need to be considered more seriously as threats to bee health.”
Research around the hazards of inert ingredients is not new, but concerns are increasing as evidence mounts. A 2014 study found that bee larvae exposed to mixtures of active and inert ingredients harmed honey bee larvae. Research published in 2017 determined that a specific organosilicone surfactant known as Slygard 309 presented unique risks to pollinators, making them more susceptible to viruses. In a similar vein, findings published earlier this year by the same research team at Royal Holloway University as the present study, found that bumblebees exposed to Roundup formulations, but not glyphosate itself, sold in the UK were the primary culprit of pollinator hazards.
Ultimately, as a 2018 paper concludes, differentiating inert ingredients from active ingredients in formulated pesticide products has no scientific basis. All ingredients in pesticide products that could endanger humans or wildlife should be tested both separately and in combination. As it stands in the United States, a pesticide product can include up to 99% inert ingredients, which may be as harmless as canola oil or as toxic as hydrochloric acid, but these are not required to be disclosed on the product label. Beyond Pesticides and its allies have sued EPA over this regulation, ending in a lackluster ruling that merely disclosed products that had already been removed from EPA’s list of allowed inerts.
As a result, public right-to-know over pesticide ingredients must come from policy changes brought about by public pressure. Beyond Pesticides runs actions every week aimed at changing the way pesticide products are reviewed and registered by EPA. Help us tell EPA that its failed pesticide program needs a new start, reoriented toward its original mission to protect public health and the wider environment.
All unattributed positions and opinions in this piece are those of Beyond Pesticides
Source: Royal Holloway University of London press release, Scientific Reports
Correction: The article has been corrected to accurately reflect the mortality rate associated with different pesticide mixtures. A separate update clarifies that the same research team at Royal Holloway University worked on both this study, and the prior Roundup formulation study.
Great write up! You’ve done a fantastic job summarising my work!
Wonderful to see this study making its way over the pond. EPA regulation is such a black hole this study literally wouldn’t have been possible in the states because pesticide labels are so vague.
2 small point-
It’s a mixture of benzisothiazol, naphthalenesulfonic acid, AND alcohol ethoxylates
The Roundup study is also by me!
November 11th, 2021 at 5:15 amAfter reading this article, I did some research on alcohol ethoxylates in Canada.
SNAP comment: In Canada, inerts are called formulants/Canada. The CAS number for alcohol ethoxylates is 84133-50-6. They are listed as a formulant in the latest PMRA formulants list (2017). It is listed in category 4B “formulants of minimum concern under specific conditions of use”. Section 4.6:”When a formulant reaches List 4B, no further regulatory action is anticipated unless the use pattern for which it is being considered is beyond that approved, in which case the PMRA will require an independent review”. A formulants are still secret except if very toxic or allergens, I suspect there is no listing of alcohol ethoxylates in pesticide formulations or on MSDS sheets. As of 18 November 2021, there are 44 PMRA registered products containing azoxystrobin, none with the name Amistar.
November 18th, 2021 at 1:51 pm