New study examines Roundup herbicide impact on honeybees

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A group of Chinese researchers has found evidence that commercial glyphosate-based herbicide products are harmful to honeybees at or below recommended concentrations.

In a paper published in the online journal Scientific Reports, researchers affiliated with the Chinese Academy of Agricultural Sciences in Beijing and the Chinese Bureau of Landscape and Forestry, said they found a range of negative impacts on honeybees when exposing the bees to Roundup – a glyphosate-based product sold by Monsanto owner Bayer AG.

The memory of the honeybees was “significantly impaired after exposure to Roundup” suggesting that chronic honeybee exposure to the weed killing chemical “may have a negative impact on the search and collection of resources and the coordination of foraging activities” by bees, the researchers said.

As well, the “climbing ability of honeybees significantly decreased after treatment with the recommended concentration of Roundup,” the researchers found.

The researchers said there is a need for a “reliable herbicide spraying early warning system” in rural areas of China because beekeepers in those areas are “usually not informed before herbicides are sprayed” and “frequent poisoning incidents of honeybees” occur.

The production of many important food crops is dependent upon honeybees and wild bees for pollination, and noted declines in bee populations has raised concerns around the world about food security.

A paper out of Rutgers University published last summer warned that “crop yields for apples, cherries and blueberries across the United States are being reduced by a lack of pollinators.”

New research adds evidence that weed killer glyphosate disrupts hormones

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New research is adding worrisome evidence to concerns that the widely used weedkilling chemical glyphosate may have the potential to interfere with human hormones.

In a paper published in the journal Chemosphere titled Glyphosate and the key characteristics of an endocrine disruptor: A review, a trio of scientists concluded that glyphosate appears to have eight out of ten key characteristics associated with endocrine disrupting chemicals . The authors cautioned, however, that prospective cohort studies are still needed to more clearly understand the impacts of glyphosate on the human endocrine system.

The authors, Juan Munoz, Tammy Bleak and Gloria Calaf, each affiliated with the University of Tarapacá in Chile, said their paper is the first review to consolidate the mechanistic evidence on glyphosate as an endocrine-disrupting chemical (EDC).

Some of the evidence suggests that Roundup, Monsanto’s well-known glyphosate-based herbicide, can alter the biosynthesis of the sexual hormones, according to the researchers.

EDCs may mimic or interfere with the body’s hormones and are linked with developmental and reproductive problems as well as brain and immune system dysfunction.

The new paper follows publication earlier this year of an assortment of animal studies that indicated glyphosate exposures impact reproductive organs and threaten fertility.

Glyphosate is the world’s most widely used herbicide, sold in 140 countries. Introduced commercially in 1974 by Monsanto Co, the chemical is the active ingredient in popular products such as Roundup and hundreds of other weed killers used by consumers, municipalities, utilities, farmers, golf course operators, and others around the world.

Dana Barr, a professor at Emory University’s Rollins School of Public Health, said the evidence “tends to overwhelmingly indicate that glyphosate has endocrine disrupting properties.”

“It’s not necessarily unexpected since glyphosate has some structural similarities with many other endocrine disrupting pesticides; however, it is more concerning because glyphosate use far surpasses other pesticides,” said Barr, who directs a program within a National Institutes of Health-funded human exposure research center housed at Emory. “Glyphosate is used on so many crops and in so many residential applications such that aggregate and cumulative exposures can be considerable.”

Phil Landrigan, director of the Global Observatory on Pollution and Health, and a professor of biology
at Boston College, said the review pulled together “strong evidence” that glyphosate is an endocrine disruptor.

“The report is consistent with a larger body of literature indicating that glyphosate has a wide range of adverse health effects – findings that overturn Monsanto’s long-standing portrayal of glyphosate as a benign chemical with no negative impacts on human health,” said Landrigan.

EDCs have been a subject of concern since the 1990s after a series of publications suggested that some chemicals commonly used in pesticides, industrial solvents, plastics, detergents, and other substances could have the capacity to disrupt connections between hormones and their receptors.

Scientists generally recognized ten functional properties of agents that alter hormone action, referring to these as ten “key characteristics” of endocrine-disruptors. The ten characteristics are as follows:

EDC’s can:

  • Alter hormone distribution of circulating levels of hormones
  • Induce alterations in hormone metabolism or clearance
  • Alter the fate of hormone-producing or hormone-responsive cells
  • Alter hormone receptor expression
  • Antagonize hormone receptors
  • Interact with or activate hormone receptors
  • Alter signal transduction in hormone-responsive cells
  • Induce epigenetic modifications in hormone-producing or hormone-responsive cells
  • Alter hormone synthesis
  • Alter hormone transport across cell membranes

The authors of the new paper said a review of the mechanistic data showed that glyphosate met all of the key characteristics with the exception of two:  “Regarding glyphosate, there is no evidence associated with the antagonistic capacity of hormonal receptors,” they said. As well, “there is no evidence of its impact on hormonal metabolism or clearance,” according to the authors.

Research over the last few decades has largely focused on links found between glyphosate and cancer, particularly non-Hodgkin lymphoma (NHL.) In 2015, the World Health Organization’s International Agency for Research on Cancer classified glyphosate as a probable human carcinogen.

More than 100,000 people have sued Monsanto in the United States alleging exposure to the company’s glyphosate-based herbicides caused them or their loved ones to develop NHL.

The plaintiffs in the nationwide litigation also claim Monsanto has long sought to hide the risks of its herbicides. Monsanto lost three out of three trials and its German owner Bayer AG has spent the last year and a half trying to settle the litigation out of court.

The authors of the new paper took note of the ubiquitous nature of glyphosate, saying “massive use” of the chemical has “led to a wide environmental diffusion,” including rising exposures tied to human consumption of the weed killer through food.

The researchers said that though regulators say the levels of glyphosate residue commonly found in foods are low enough to be safe, they “cannot rule out” a “potential risk” to people consuming foods containing contaminated with the chemical,  particularly grains and other plant-based foods, which often have higher levels than milk, meat or fish products.

U.S. government documents show glyphosate residues have been detected in a range of foods, including organic honey, and granola and crackers.

Canadian government researchers have also reported glyphosate residues in foods. One report issued in 2019 by scientists from Canada’s Agri-Food Laboratories at the Alberta Ministry of Agriculture and Forestry found glyphosate in 197 of 200 samples of honey they examined.

Despite the concerns about glyphosate impacts on human health, including through dietary exposure, U.S. regulators have steadfastly defended the safety of the chemical. The Environmental Protection Agency maintains that it has not found any human health risks from exposure to glyphosate.”

Glyphosate in chicken poop used as fertilizer is hurting food production, researchers say

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Scientists brought more bad news to light regarding the widely used herbicide glyphosate, better known as Roundup, in a new research paper published this month.

Researchers from the University of Turku in Finland revealed in a paper published in the journal  Science of The Total Environment that manure from poultry used as fertilizer can decrease crop yields when the manure contains residues of glyphosate-based herbicides, such as Roundup. Fertilizers are meant to increase crop production, so the evidence that glyphosate residues can have the opposite effect is significant.

Poultry litter, as the manure is called, is often used as a fertilizer, including in organic agriculture, because it is considered rich in essential nutrients. Use of the poultry litter as fertilizer has been growing both in farming and in horticulture and home gardens.

While use is growing, the “possible risks associated with the accumulation of agrochemicals in poultry manure are still largely ignored,” the Finland researchers warned.

Organic farmers have been growing increasingly worried about traces of glyphosate in manure fertilizer that is allowed in organic production, but many in the industry are reluctant to publicize the issue.

Farmers spray glyphosate directly onto a number of crops grown around the world, including soybeans, corn, cotton, canola and other crops genetically engineered to withstand glyphosate treatments. They also often directly spray such crops as wheat and oats, which are not genetically engineered – shortly before harvest to dry the crops out.

Given the amount of glyphosate-based herbicides used to treat crops that are used in animal feed, as well as the amount of manure used as fertilizer, “we should definitely be aware that this kind of a risk exists,” said one of the authors of study, Anne Muola.

“Nobody seems very eager to talk too loudly about it.” Muola noted.

The heavy use of glyphosate herbicides directly onto food crops has been promoted by Monsanto – now a unit of Bayer AG – since the 1990s, and glyphosate use is so ubiquitous that residues are commonly found in food, water and even air samples.

Because there are glyphosate residues in human and animal food, detectable glyphosate levels are commonly found in human urine and animal manure.

These glyphosate residues in fertilizer are a problem for growers for many reasons, according to the Finland researchers.

“We found that poultry manure can accumulate high residues of (glyphosate-based herbicides), decrease plant growth and reproduction, and thus inhibit the growth-promoting effects of manure when applied as fertilizer,” the paper states. “These results demonstrate that the residues pass through the digestive process of birds, and more importantly, they persist in the manure fertilizer over long periods.”

The researchers said the glyphosate residues can persist in ecological systems, affecting several non-target organisms over many years.

The consequences, they said, include decreased efficiency of manure as fertilizer; long-lasting glyphosate-based herbicide contamination of agricultural cycles; “uncontrolled” glyphosate contamination of non-target areas; increased threat to “vulnerable non-target organisms,” and an increased risk of emerging resistances to glyphosate.

The researchers said more studies should be done to reveal the extent of glyphosate contamination in organic fertilizers and how that impacts sustainability.

The Finland research adds to evidence of the dangers of glyphosate residues in fertilizer, according to agricultural experts.

“The impacts of glyphosate residue that have accumulated in poultry excrements is a largely overlooked area of research,”  said Rodale Institute soil scientist, Dr. Yichao Rui. “But what research does exist has shown that those residues can have a negative effect on crops, if poultry manure was used as a fertilizer. Glyphosate residues in fertilizers have been shown to have negative effects on plants, soil microbiomes, and microbes associated with plants and animals including humans through the food chain. When this contamination is unintentionally spread through fertilizer, it places a severe strain on biodiversity and ecosystem functions and services.”

Worldwide 9.4 million tons of glyphosate have been sprayed on fields – enough to spray nearly half a pound of Roundup on every cultivated acre of land in the world.

In 2015, the World Health Organization’s International Agency for Research on Cancer (IARC) classified glyphosate as “probably carcinogenic to humans” after reviewing years of published and peer-reviewed scientific studies. The team of international scientists found there was a particular association between glyphosate and non-Hodgkin lymphoma.

Tens of thousands of people in the United States suffering from non-Hodgkin lymphoma have sued Monsanto, and in three trials held to date, juries have found that the company’s glyphosate herbicides were to blame for causing the cancers.

Additionally, an assortment of animal studies released this summer indicate that glyphosate exposures impact reproductive organs and could threaten fertility, adding fresh evidence that the weed killing agent might be an endocrine disruptor. Endocrine disrupting chemicals may mimic or interfere with the body’s hormones and are linked with developmental and reproductive problems as well as brain and immune system dysfunction.