Glyphosate is the most widely used herbicide in the world and the active ingredient in Roundup. Since its introduction in the 1970’s, use of glyphosate-based herbicides has increased 100-fold. Of chief concern is the fact that the guidelines which set the allowable limits regarding glyphosate exposure are mostly based on studies conducted 30 years ago – well before the substantial increase in use of glyphosate-based herbicides. Today, glyphosate residue can be found in many commonly eaten foods, but the long term impact on health due to low level exposure remains unknown.<\/p>\n\n\n\n
Each year, 240 million pounds of glyphosate-based herbicides are used in the U.S., far more than in any other country in the world. Corn, barley, soybeans, wheat, and beans are just a few of the crops sprayed with glyphosate-based herbicides (GBH). The main reason for the dramatic increase in the use of GBH over the last twenty years has do to with genetically-modified crops. Originally developed to tolerate glyphosate-based herbicides so that only the weeds would be killed, genetically modified crops initially seemed to provide a safer alternative to the use of large amounts of herbicides.<\/p>\n\n\n\n
The problem is that nature is always one step ahead of man. Much like the “super bugs” created by the overuse of antibiotics, the weeds themselves developed resistance to GBH. This has lead to the use of even greater amounts of this herbicide and new formulations of herbicides. In some cases, the overgrowth of “super weeds” has become so severe that it has forced farmers to not only use a more toxic combination of herbicides, such as the spraying of glyphosate and 2,4-D, but to return to certain agricultural practices that can result in greater environmental pollution. Some farmers have now resorted to plowing under the super weeds and mixing herbicides into the soil in order to avoid completely losing their fields to an infestation of “super weeds”.<\/p>\n\n\n\n
The use of GBH is not limited to agricultural settings alone. Urban areas, too, rely heavily on GBH to keep weeds in check. Wherever GBH is used to control weed growth – be it on lawns or in parks, contamination of surface and groundwater is at risk. An assessment of soil and water samples published in 2014 in the Journal of the American Water Resource Association found glyphosate and its metabolite, AMPA, “frequently in soils and sediment, ditches and drains, precipitation, rivers, and streams; less frequently in lakes, ponds, and wetlands; soil water; and groundwater. Concentrations of glyphosate were below the levels of concern for humans or wildlife; however, pesticides are often detected in mixtures. Ecosystem effects of chronic low-level exposures to pesticide mixtures are uncertain. The environmental health risk of low-level detections of glyphosate, AMPA, and associated adjuvants and mixtures remain to be determined.”<\/p>\n\n\n\n
According to the EPA, “labeled uses of glyphosate include over 100 terrestial food crops as well as other non-agricultural sites, such as greenhouses, aquatic areas, and residential areas.” Glyphosate residue has been found in wheat and soybeans, so that humans are exposed to it through direct ingestion of GBH- contaminated foods. Livestock are also exposed to GBH through residue on animal fodder. Other sources of exposure for humans occur via inhalation of airborne particles during spraying; direct contact with an area where GBH has been applied or by handling the mixture; or via contaminated water sources.<\/p>\n\n\n\n
The main question surrounding exposure to GBH has to do with the risk it poses to human health over the long term. As mentioned earlier, past safety assessments regarding acceptable exposure limits are based on studies performed three decades ago – well before the use of GBH skyrocketed and well before the more recent practice of spraying crops with GBH just before harvest.<\/p>\n\n\n\n
An essay published in 2016 in The Journal of Epidemiology and Community Health found “the current safety standards for GBH are outdated and may fail to protect public health or the environment.” Here, the authors point to the need for the EPA to re-examine safety standards in light of more recent research. “In the US EPA’s 1993 registration review of GBHs, for example, 73% of the almost 300 citations were published prior to 1985; importantly, only 11 were peer-reviewed. A search of PubMed (conducted 6 November 2016) reveals more than 1500 published studies on glyphosate in the last decade alone. It is incongruous that safety assessments of the most widely used herbicide on the planet rely largely on fewer than 300 unpublished, non-peer-reviewed studies while excluding the vast, modern literature on glyphosate effects.”<\/p>\n\n\n\n
Since the U.S. does not monitor glyphosate levels in humans, there is no available data that looks at the long-term impact of low levels of GBH on human health. The authors stress the urgent need for monitoring of glyphosatge and its degradation products in humans and question whether the EPA’s current method of testing is sufficient to “address the full complement of health effects that could be induced by exposure to glyphosate-based herbicides (GBHs)”.<\/p>\n\n\n\n
Glyphosate toxicity has been linked with kidney and liver problems as well as tumors in rats exposed to GBH. In humans, one study found an association between Non-Hodgkins Lymphoma and glyphosate exposure. In 2015, glyphosphate was classified as a probable human carcinogen by the World Health Organization’s International Agency for Research on Cancer (IARC). Since that classification, some countries, including Sweden and France, have proposed a ban on glyphosate. In its Glypohosate Issue Paper published in September 2016, the EPA discussed it’s review of the risks posed to humans and the environment by glyphosate, stating:<\/p>\n\n\n\n
“Currently, glyphosate is undergoing Registration Review1 , a program where all registered pesticides are reviewed at least every 15 years as mandated by the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The initial docket opening for glyphosate occurred in 2009 with the publication of the human health scoping document and preliminary work plan2. As part of this process, the hazard and exposure of glyphosate are reevaluated to determine its potential risk to human and environmental health. Risks are assessed using current practices and policies to ensure pesticide products can still be used safely. Registration Review also allows the agency to incorporate new science. For human health risk assessment, both non-cancer and cancer effects are evaluated for glyphosate and its metabolites, aminomethylphosphonic acid (AMPA) and Nacetyl-glyphosate; however, this document will focus on the cancer effects only. EPA expects to complete its complete human health risk assessment in 2017 that will include an assessment of risk from anticipated exposures resulting from registered uses of glyphosate in residential and occupational settings.”<\/p>\n\n\n\n
The need for monitoring of GBH exposure in humans is warranted. An assessment performed in 2016 by the Alliance for Natural Health found traces of glyphosate – below the acceptable limit – in many common foods, including flour, corn flakes, bagels, yogurt, and potatoes. Most concerning is the fact that they found traces of GBH in organic eggs and dairy creamers, revealing that this herbicide does accumulate in livestock which are fed GBH-treated grain.<\/p>\n\n\n\n