Weed Killer Residues Found in 98 Percent of Canadian Honey Samples

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Study is the latest evidence that glyphosate herbicides are so pervasive that residues can be found in foods not produced by farmers using glyphosate.

This article was originally published in Environmental Health News.

By Carey Gillam

As U.S. regulators continue to dance around the issue of testing foods for residues of glyphosate weed killers, government scientists in Canada have found the pesticide in 197 of 200 samples of honey they examined.

The authors of the study, all of whom work for Agri-Food Laboratories at the Alberta Ministry of Agriculture and Forestry, said the prevalence of glyphosate residues in honey samples – 98.5 percent – was higher than what was reported in several similar studies done over the last five years in other countries.

Glyphosate is the world’s most widely used herbicide and is the active ingredient in Roundup brands as well as hundreds of others sold around the world for agriculture and other purposes. Use has grown dramatically over the last 25 years and consumers have become concerned about residues of the herbicide in their food.

The data provides fresh evidence that glyphosate herbicides are so pervasive in the environment that residues can be found even in a food that is not produced by farmers using glyphosate. The researchers noted in their report that they ran into delays trying to calibrate their testing equipment “due to difficulties encountered in obtaining a honey sample which did not contain traces of glyphosate.”

Bees pick up traces of pesticides as they move from plant to plant, unintentionally transferring residues from crops or weeds sprayed with glyphosate back to their hives.

In a different study, researchers on the Hawaiian island of Kauai took honey directly from 59 bee hives and found glyphosate residues in 27 percent of them. The Hawaiian researchers said bee hives located near farming areas as well as golf courses where glyphosate is used had higher concentrations of the pesticide.

The Canadian report also comes amid growing evidence that glyphosate herbicides can cause cancer, specifically non-Hodgkin’s lymphoma. On Tuesday a jury in San Francisco unanimously found that Roundup, a glyphosate-based herbicide made popular by chemical manufacturer Monsanto Co., use was a “substantial factor” in causing non-Hodgkin’s lymphoma in a California man. That echoed a similar unanimous jury verdict handed down in August in a separate case in which a cancer victim also alleged his disease was due to exposure to Monsanto’s glyphosate-based herbicides.

Both verdicts came after plaintiffs’ lawyers presented evidence of multiple studies showing the cancer-causing potential of glyphosate herbicides, including one published last month in a journal whose editor is a senior scientist at the U.S. Environmental Protection Agency (EPA).

The Canadians’ decision to examine honey samples for glyphosate comes after a similar look at honey samples by a U.S. Food and Drug Administration chemist in 2017. That FDA scientist found all 28 honey samples he looked at had traces of glyphosate, with 61 percent of the samples having enough glyphosate to be measured. The other samples had residues of the herbicide too slight to measure.

“Safe” levels

The Canadian report, published in a journal called Food Additives & Contaminants: Part A, said that glyphosate is currently an active ingredient in 181 herbicides registered for use in Canada and its widespread use has made it commonly found in the environment.

The study authors pointed out that Canada, like the United States, does not have a legal standard for how much of the herbicide is considered safe in honey. Regulators in different countries set what are referred to as “maximum residue limits” (MRLs) and tell consumers their food is safe if pesticide residues remain below the MRLs. In Europe, the MRL for glyphosate in honey is 0.05 mg/kg, also expressed as 50 μg/kg.

The Canadian study authors said that all of the levels they found were below the European limit, though the highest was just barely within the legal limit. Because the residues did not exceed the MRL, they said, “the risk to consumer health appears to be quite low based on the residues detected.”

Several of the residue levels found by the FDA scientist in U.S. honey were above that so-called safe level that applies in the European Union. But the FDA, like the U.S. Department of Agriculture (USDA) and EPA, assert that as long as pesticide residues are below the legal MRLs, they are not harmful.

Many scientists do not agree that MRLs actually are protective of public health, however.

“People think the standards are protective of public health but they are not,” Dr. Philip Landrigan, director of the Global Public Health Program at Boston College, told EHN. “The optimal amount” of pesticide residues in food is “zero,” he said. “Remember, many of the people eating honey are children.”

A team of Harvard scientists published a commentary in October stating that more research about potential links between disease and consumption of pesticide residues is “urgently needed” as more than 90 percent of the U.S. population has pesticide residues in their urine and blood.

The United States has fallen behind Europe, Canada and other countries in testing foods for residues of glyphosate. Though both the FDA and the USDA annually test thousands of food samples for pesticide residues and report the data in reports, both agencies have not included glyphosate in their yearly testing programs.

In fact, the honey test data gathered by the FDA chemist was never published by the FDA and was not included in the agency’s first-ever glyphosate testing data that was released late last year as part of the annual test data report.

The USDA has similarly balked at testing foods for glyphosate residues for decades. The agency planned to start limited testing in 2017 but dropped the plan with little explanation only a couple of months before testing was to have started.

Legislative push for testing

Amid all the concerns about glyphosate and residues in food, U.S. Rep Rosa DeLauro of Connecticut this month introduced a measure called the “Keep Food Safe From Glyphosate Act.” The bill would require the USDA to routinely test food samples for glyphosate residues.

The bill would also ban the spraying of glyphosate as a desiccant on oats. The practice is employed by some farmers to dry their oats before harvesting. It makes harvest more efficient but leaves higher residues on finished oat-based foods.

Monsanto, now a unit of Bayer AG, has marketed glyphosate for use on oats as a desiccant for years, and the company also has successfully convinced the EPA to raise the MRL for glyphosate residues allowed in oat products. In 1993, for example, the EPA had a tolerance for glyphosate in oats at 0.1 parts per million (ppm) but in 1996 Monsanto asked EPA to raise the tolerance to 20 ppm and the EPA did as asked. In 2008, at Monsanto’s suggestion, the EPA again looked to raise the tolerance for glyphosate in oats, this time to 30 ppm.

In her bill, DeLauro is looking to slash the MRL for glyphosate residues in oats to 0.1 ppm.

Canadian farmers are among the world’s top producers of oats, and desiccation with glyphosate has been a common practice there.

Health Canada has rejected concerns about glyphosate safety, saying: “No pesticide regulatory authority in the world currently considers glyphosate to be a cancer risk to humans at the levels at which humans are currently exposed.”

In addition to testing for glyphosate residues, the Canadian scientists also tested for residues of glyphosate’s main degradation product, a metabolite called aminomethylphosphonic acid (AMPA). Like glyphosate, AMPA has long been considered to have low toxicity. AMPA was detected in 198 of the 200 samples up to a concentration of 50.1 μg/kg.

“The contribution of glyphosate and AMPA residues present in the ambient environment to contamination of plant nectar and subsequently honey itself is further complicated by the variations in the levels of these compounds in environmental matrices such as soil and surface water,” the scientists said in their report.

The scientists also looked for residues of the weed killer glufosinate and found residues of that herbicide in 125 of 200 samples, with the maximum concentration detected being 33 μg/kg.

Glufosinate is the active ingredient in BASF’s Liberty herbicide.

Glyphosate Fact Sheet: Cancer and Other Health Concerns

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Glyphosate, a synthetic herbicide patented in 1974 by the Monsanto Company and now manufactured and sold by many companies in hundreds of products, has been associated with cancer and other health concerns. Glyphosate is best known as the active ingredient in Roundup-branded herbicides, and the herbicide used with “Roundup Ready” genetically modified organisms (GMOs).

Herbicide tolerance is the most prevalent GMO trait engineered into food crops, with some 90% of corn and 94% of soybeans in the U.S. engineered to tolerate herbicides, according to USDA data. A 2017 study found that Americans’ exposure to glyphosate increased approximately 500 percent since Roundup Ready GMO crops were introduced in the U.S in 1996. Here are some key facts about glyphosate:

Most Widely Used Pesticide

According to a February 2016 study, glyphosate is the most widely used pesticide: “In the U.S., no pesticide has come remotely close to such intensive and widespread use.” Findings include:

  • Americans have applied 1.8 million tons of glyphosate since its introduction in 1974.
  • Worldwide 9.4 million tons of the chemical has been sprayed on fields – enough to spray nearly half a pound of Roundup on every cultivated acre of land in the world.
  • Globally, glyphosate use has risen almost 15-fold since Roundup Ready GMO crops were introduced.

Cancer Concerns

The scientific literature and regulatory conclusions regarding glyphosate and glyphosate-based herbicides show a mix of findings, making the safety of the herbicide a hotly debated subject:

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.

At the time of the IARC classification, the Environmental Protection Agency (EPA) was conducting a registration review. The EPA’s Cancer Assessment Review Committee (CARC) issued a report in September 2016 concluding that glyphosate was “not likely to be carcinogenic to humans” at doses relevant to human health. In publishing the CARC report, the EPA said that it was beginning work with the National Toxicology Program to investigate the mechanisms and toxic effects of glyphosate formulations. The agency then convened a Scientific Advisory Panel (SAP) in December 2016 to review the CARC report conclusion that glyphosate was not likely to be carcinogenic. The scientific advisory panel members were divided in their assessment of EPA’s work, with some finding the EPA erred in how it evaluated certain research. Additionally, the EPA’s Office of Research and Development determined that the agency’s Office of Pesticide Programs had not followed proper protocols in its evaluation of glyphosate. An ORD memo stated that the government scientists agreed in part with IARC and believed EPA was not properly following guidelines in coming to the conclusion that glyphosate was not likely to be carcinogenic. ORD said the evidence could be deemed to support a “likely” carcinogenic or “suggestive” evidence of carcinogenicity classification. Nevertheless the EPA issued a draft report on glyphosate in December 2017 continuing to hold that the chemical is not likely to be carcinogenic.

EFSA, ECA, WHO/FAO JMPR: The European Food Safety Authority and the European Chemicals Agency have said glyphosate is not likely to be carcinogenic to humans. But a March 2017 report by environmental and consumer groups argued that regulators relied improperly on research that was directed and manipulated by the chemical industry.

The WHO/FAO Joint Meeting on Pesticide Residues determined that glyphosate was unlikely to pose a carcinogenic risk to humans from exposure through the diet, though the finding was tarnished by conflict of interest concerns after it was revealed that certain members of the group, including its chair, worked for the International Life Sciences Institute, a group funded in part by Monsanto and one of its lobbying organizations.

California OEHHA: On March 28, 2017, the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment confirmed that it would add glyphosate to California’s Proposition 65 list of chemicals known to cause cancer. Monsanto sued to block the action but the case was dismissed. In a separate case, the court found that California could not require cancer warnings for products containing glyphosate. On June 12, 2018, the United States District Court for the Eastern District of California denied the California Attorney General’s request for the court to reconsider the decision. The court found that California could only require commercial speech that disclosed “purely factual and uncontroversial information,” and the science surrounding glyphosate carcinogenicity was not proven.

Agricultural Health Study: A long-running U.S. government-backed prospective cohort study of farm families in Iowa and North Carolina has not found any connections between glyphosate use and non-Hodgkin lymphoma, but the researchers reported that “among applicators in the highest exposure quartile, there was an increased risk of acute myeloid leukemia (AML) compared with never users…” The most recent published update to the study was made public in late 2017.

New studies in 2019 report cancer links and concerns about the validity of the EPA classification:  

Cancer Lawsuits

More than 11,000 people have filed suit against Monsanto Company (now Bayer) alleging that exposure to Roundup herbicide caused them or their loved ones to develop non-Hodgkin lymphoma, and that Monsanto covered up the risks. As part of the discovery process, Monsanto has had to turn over millions of pages of its internal records. We are posting these Monsanto Papers as they become available here. For news and tips about the ongoing legislation, see Carey Gillam’s Roundup Trial Tracker. The first two trials ended with juries ruling that Monsanto’s weed killer was a substantial contributing factor in causing the plaintiffs to develop non-Hodgkin lymphoma, and giving large awards for liability and damages.  

Monsanto influence in research: In March 2017, the federal court judge unsealed some internal Monsanto documents that raised new questions about Monsanto’s influence on the EPA process and about the research regulators rely on. The documents suggest that Monsanto’s long-standing claims about the safety of glyphosate and Roundup do not necessarily rely on sound science as the company asserts, but on efforts to manipulate the science.

A study for the European Parliament published January 2019 asserts that the EU approval of glyphosate was based on plagiarized text from Monsanto. The study found plagiarism in 50.1 percent of chapters dealing with the assessment of published studies on health risks related to glyphosate in Germany’s Federal Institute for Risk Assessment, including whole paragraphs and entire pages of plagiarized text.

More information about scientific interference:

Endocrine Disruption and Other Health Concerns

Some research suggests that glyphosate may be an endocrine disruptor. It has also been linked to liver disease, birth defects and reproductive problems in laboratory animals; and may kill beneficial gut bacteria and damage the DNA in human embryonic, placental and umbilical cord cells. A 2019 study in a Nature journal reported increases in obesity, reproductive and kidney diseases, and other problems in the second- and third-generation offspring of rats exposed to glyphosate. See the study and Washington State University press release.

Recent studies have shown adverse biological effects from low-dose exposures to glyphosate at levels to which people are routinely exposed.

  • A birth cohort study in Indiana published in 2017 – the first study of glyphosate exposure in US pregnant women using urine specimens as a direct measure of exposure – found detectable levels of glyphosate in more than 90% of the pregnant women tested and found the levels were significantly correlated with shortened pregnancy lengths.
  • A 2018 ecological and population study conducted in Argentina found high concentrations of glyphosate in the soil and dust in agricultural areas that also reported higher rates of spontaneous abortion and congenital abnormalities in children, suggesting a link between environmental exposure to glyphosate and reproductive problems. No other relevant sources of pollution were identified.
  • A 2017 study associated chronic, very low-level glyphosate exposures to non-alcoholic fatty liver disease in rats. According to the researchers, the results “imply that chronic consumption of extremely low levels of a GBH formulation (Roundup), at admissible glyphosate-equivalent concentrations, are associated with marked alterations of the liver proteome and metabolome,” the biomarkers for NAFLD.
  • A 2018 rat study conducted by the Ramazzini Institute reported that low-dose exposures to Roundup at levels considered safe significantly altered the gut microbiota in some of the rat pups. Another 2018 study reported that higher levels of glyphosate administered to mice disrupted the gut microbiota and caused anxiety and depression-like behaviors.
  • A 2018 rat study by Argentinian researchers linked low-level perinatal glyphosate exposures to impaired female reproductive performance and congenital anomalies in the next generation of offspring.

Glyphosate has also been linked by recent studies to harmful impacts on bees and monarch butterflies.

Desiccation

Some farmers use glyphosate on non-GMO crops such as wheat, barley, oats, and lentils to dry down the crop ahead of harvest in order to accelerate the harvest. This practice, known as desiccation, may be a significant source of dietary exposure to glyphosate.

Glyphosate in Food: U.S. Drags Its Feet on Testing

The USDA quietly dropped a plan to start testing food for residues of glyphosate in 2017. Internal agency documents obtained by U.S. Right to Know show the agency had planned to start testing over 300 samples of corn syrup for glyphosate in April 2017. But the agency killed the project before it started. The U.S. Food and Drug Administration began a limited testing program in 2016, but the effort was fraught with controversy and internal difficulties and the program was suspended in September 2016. Both agencies have programs that annually test foods for pesticide residues but both have routinely skipped testing for glyphosate.

Before the suspension, one FDA chemist found alarming levels of glyphosate in many samples of U.S. honey, levels that were technically illegal because there have been no allowable levels established for honey by the EPA. Here is a recap of news about glyphosate found in food:

Pesticides in Our Food: Where’s the Safety Data?

USDA data from 2016 shows detectable pesticide levels in 85% of more than 10,000 foods sampled, everything from mushrooms to grapes to green beans. The government says there are little to no health risks, but some scientists say there is little to no data to back up that claim. See “Chemicals on our food: When “safe” may not really be safe: Scientific scrutiny of pesticide residue in food grows; regulatory protections questioned,” by Carey Gillam (11/2018).

Statements From Scientists and Health Care Providers