I’ve already expressed my concern over the fact that U.S. government agencies recently unleashed a ticking bomb with regard to the genetically engineered (GE) “superweed” problem we’re already experiencing in the United States when the U.S. Department of Agriculture (USDA) deregulated GE corn and GE soybeans that can survive being sprayed with two pesticides that would kill their non-engineered relatives, and the Environmental Protection Agency (EPA) approved the herbicide cocktail, Enlist Duo™, comprised of the two pesticides that can be sprayed on those GE crops with impunity. Supporting this “pesticide treadmill” seems the antithesis of “sustainable” agriculture to me.

But after reading EPA’s “Response to Public Comments Received Regarding New Uses of Enlist Duo™ on Corn and Soybeans,” I have an additional concern: the toxicity of 2,4-D, one of the two pesticides comprising Enlist Duo™, to animals.

EPA acknowledges that,“should actual exposures [to 2,4-D] occur, direct effects (risk quotients…above the level of concern) may be possible only [my emphasis] for mammals, birds, reptiles, land-phase amphibians and terrestrial plants.” EPA also noted that “Acute exposure risk concerns were identified for both listed [i.e. endangered or threatened] and non-listed birds in the screening level assessment.”

But, while I find these “concerns” mentioned by EPA, well… concerning–especially since, as reported in the Huffington Post, the USDA predicted that 2,4-D use could now increase by an estimated 200-600 percent by the year 2020–the agency, apparently, does not.

And the difference in our perspectives over 2,4-D toxicity to organisms other than corn and soybean weeds appears to boil down to the issue of “exposure.”

As explained by the agency: “EPA requires a suite of toxicological data on mammals, birds, honeybees, freshwater fish and invertebrates, estuarine/marine fish and invertebrates, aquatic plants, and terrestrial plants. The purpose of the data is to determine the toxicity of the pesticide when direct exposures occur. This is known as “hazard” and is one of two components that make up “risk.” The second consideration is “exposure.” Exposure constitutes how much of the pesticide will come into contact with an organism. “Risk” is a combination of the hazard of the pesticide and the anticipated exposure of the pesticide….The risk assessment for 2,4-D choline salt incorporates both the hazard and exposure components into its conclusions; thus although it may be toxic to some groups of organisms [my emphasis] [but remember, only “mammals, birds, reptiles, land-phase amphibians and terrestrial plants”], the risk varies proportionately with exposure.”

And there’s the rub.

To me, spraying 200-600 percent more 2,4-D on corn and soybean crops, the largest crops grown in the U.S., is bound to “expose” mammals, birds, reptiles, land-phase amphibians and terrestrial plants to 2,4-D. And that exposure to 2,4-D, combined with the toxicity hazard it presents to “some groups of organisms” could constitute substantial “risk” to those organisms.

But EPA seems to believe that restrictions it has mandated for Enlist Duo™ will adequately limit exposure. As the agency put it: “By requiring pesticide application restrictions that limit off-site exposure [my emphasis] to levels below effects thresholds of the most sensitive taxonomic group, the action area (the geographic extent to where effects can reasonably be expected to occur), is limited to the directly treated footprint of the soy or corn field [my emphasis]. Consequently, no direct or indirect effects are expected for threatened and endangered species….” EPA summed up the situation this way: “When these types of information were considered, the endangered species assessment addendum concluded that there were no direct risk concerns for mammals, birds, reptiles, land-phase amphibians, and terrestrial plants.”

In drawing this conclusion, EPA considered “species specific biology, geographic location, and the ability of spray drift mitigation measures to reduce the geographic extent of exposures of concern to a limit of the boundaries of the treatment site [my emphasis].”

But the bottom line is that even if EPA’s restrictions for Enlist Duo™ are followed to the letter, all “treatment site[s],” i.e. potentially all fields of GE corn or GE soybeans in the six states for which EPA has allowed registration of Enlist Duo™–Illinois, Indiana, Iowa, Ohio, South Dakota and Wisconsin, present “exposures of concern” to sensitive mammals, birds, reptiles, land-phase amphibians and terrestrial plants which might wander into those fields.

So unless those “treatment sites” are all fenced and netted (and even if they were), I predict that sensitive mammals, birds, reptiles, land-phase amphibians and terrestrial plants will make their way into those fields of GE corn and GE soybeans and get themselves exposed to 2,4-D.

As I recall, mammals (mainly squirrels) often wandered in and out of “contained” field trials of Flavr Savr™ tomatoes two+ decades ago. GE corn and GE soybean fields could be just as inviting to mammals, birds and other animals today.

The EPA is currently considering whether to register Enlist Duo™ in ten additional states: Arkansas, Kansas, Louisiana, Minnesota, Mississippi, Missouri, Nebraska, North Dakota, Oklahoma and Tennessee. For the sake of the mammals, birds, reptiles and land-phase amphibians in those states that are sensitive to 2,4-D, I hope that registration is denied.