New study shows that neonicotinoid insecticides pose significant threats to insects, soil and water
Most GM crop seeds are coated in neonicotinoid insecticides. As the article below points out, nearly half of soy seeds and up to 100% of corn seeds are treated with these toxins.
The new study featured in The Guardian article below is here. We've posted the abstract at the bottom of the article.
America's agriculture is 48 times more toxic than 25 years ago. Blame neonics
Kendra Klein and Anna Lappé
The Guardian, 7 Aug 2019
* A new study shows that the class of insecticides called neonicotinoids poses significant threats to insects, soil and water
More than 50 years ago, Rachel Carson warned of a “silent spring”, the songs of robins and wood thrush silenced by toxic pesticides such as DDT. Today, there is a new pesticide specter: a class of insecticides called neonicotinoids. For years, scientists have been raising the alarm about these bug killers, but a new study reveals a more complete picture of the threat they pose to insect life.
First commercialized in the 1990s, neonicotinoids, or neonics for short, are now the most widely used insecticides in the world. They’re used on over 140 crops, from apples and almonds to spinach and rice. Chemically similar to nicotine, they kill insects by attacking their nerve cells.
Neonics were pitched as an answer to pests’ increasing resistance to the reigning insecticides. But in an effort to more effectively kill pests, we created an explosion in the toxicity of agriculture not just for unwanted bugs but for the honeybees, ladybugs, beetles and the vast abundance of other insects that sustain life on Earth.
What we now know is that neonics are not only considerably more toxic to insects than other insecticides, they are far more persistent in the environment. While others break down within hours or days, neonics can remain in soils, plants and waterways for months to years, killing insects long after they’re applied and creating a compounding toxic burden.
The new study, published in the science journal PLOS One, designed a way to quantify this persistence and combine it with data on the toxicity and total pounds used of neonics and other insecticides. For the first time, we have a time-lapse of impact: we can compare year-to-year changes in the toxicity of US agriculture for insects. The results? Since neonics were first introduced 25 years ago, US agriculture has become 48 times more toxic to insect life, and neonics are responsible for 92% of that surge in toxicity.
Looking at this toxic time-lapse, another interesting detail emerges: there’s a dramatic increase in the toxic burden of US agriculture for insects starting in the mid-2000s. That’s when beekeepers began reporting significant losses of their hives. It’s also when the pesticide companies that manufacture neonics, Bayer and Syngenta, found a lucrative new use for these chemicals: coating the seeds of crops like corn and soy that are grown on millions of acres across the country. These seed coatings now account for the vast majority of neonic use in the US.
Neonics are “systemic”, meaning they are water soluble and therefore taken up by the plant itself, making its nectar, pollen, and fruit – all of it – toxic. Only about 5% of a seed coating is absorbed by the plant, the remainder stays in the soil and can end up in rivers, lakes and drinking water with its runoff causing harm to wildlife and, as emerging evidence shows, to people.
This study comes on the heels of the first analysis of global insect populations, which found 40% of species face extinction, with near total insect loss possible by century’s end, driven in part by pesticides, with neonics a particular concern.
For all of this harm, farmers get few, if any, benefits from neonic seed coatings. According to the US Environmental Protection Agency, they provide “little or no overall benefits to soybean production”, though nearly half of soybean seeds in the US are treated. Similar analyses have found the same for corn, yet up to 100% of US corn seeds are treated.
All this risk without reward has led some regulators to take action. The European Union voted to ban the worst neonics in 2018. But the US government has so far failed to act. Chemical company lobbying can explain much of this inaction. Bayer, maker of the most widely used neonics, spent an estimated $4.3m lobbying in the US on behalf of its agricultural division in 2017.
Not only has the EPA stalled scientific review of neonics, last year, the Fish and Wildlife Service reversed an Obama-era ban on use of these dangerous insecticides in wildlife refuges. Congress could change this. Democratic representative Earl Blumenauer’s Saving America’s Pollinators Act would ban neonicotinoids and other systemic, pollinator-toxic insecticides. The bill has 56 co-sponsors, but faces a major hurdle clearing the House agriculture committee given that the chairman representative, Collin Peterson, a Democrat from Minnesota, counts Bayer and the pesticide industry’s trade association, Croplife America, among his top contributors.
Beyond a ban, we need a concerted effort to transition US agriculture away from dependence on pesticides and toward ecological methods of pest control. We already know how to do this. Research shows that organic farms support up to 50% more pollinating species and help other beneficial insects flourish. And by eliminating neonics and some 900 other active pesticide ingredients, they protect human health, too.
More than five decades ago, Rachel Carson warned that the war we are waging against nature with toxic pesticides is inevitably a war against ourselves. That is as true today as it was then. For the sake of the birds and bees – and all of us – this war must end.
Kendra Klein, PhD, is senior staff scientist at Friends of the Earth US. Anna Lappé is the co-founder of two national food and sustainability organizations and is working on a book on pesticides and our food.
An assessment of acute insecticide toxicity loading (AITL) of chemical pesticides used on agricultural land in the United States
Michael DiBartolomeis, Susan Kegley, Pierre Mineau, Rosemarie Radford, Kendra Klein
PLOS One, August 6, 2019 https://doi.org/10.1371/journal.pone.0220029
We present a method for calculating the Acute Insecticide Toxicity Loading (AITL) on US agricultural lands and surrounding areas and an assessment of the changes in AITL from 1992 through 2014. The AITL method accounts for the total mass of insecticides used in the US, acute toxicity to insects using honey bee contact and oral LD50 as reference values for arthropod toxicity, and the environmental persistence of the pesticides. This screening analysis shows that the types of synthetic insecticides applied to agricultural lands have fundamentally shifted over the last two decades from predominantly organophosphorus and N-methyl carbamate pesticides to a mix dominated by neonicotinoids and pyrethroids. The neonicotinoids are generally applied to US agricultural land at lower application rates per acre; however, they are considerably more toxic to insects and generally persist longer in the environment. We found a 48- and 4-fold increase in AITL from 1992 to 2014 for oral and contact toxicity, respectively. Neonicotinoids are primarily responsible for this increase, representing between 61 to nearly 99 percent of the total toxicity loading in 2014. The crops most responsible for the increase in AITL are corn and soybeans, with particularly large increases in relative soybean contributions to AITL between 2010 and 2014. Oral exposures are of potentially greater concern because of the relatively higher toxicity (low LD50s) and greater likelihood of exposure from residues in pollen, nectar, guttation water, and other environmental media. Using AITL to assess oral toxicity by class of pesticide, the neonicotinoids accounted for nearly 92 percent of total AITL from 1992 to 2014. Chlorpyrifos, the fifth most widely used insecticide during this time contributed just 1.4 percent of total AITL based on oral LD50s. Although we use some simplifying assumptions, our screening analysis demonstrates an increase in pesticide toxicity loading over the past 26 years, which potentially threatens the health of honey bees and other pollinators and may contribute to declines in beneficial insect populations as well as insectivorous birds and other insect consumers.