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Mar
Implications for Human Health: Glyphosate-Related Soil Erosion Re-Releases Toxic Pesticides from Soil
(Beyond Pesticides, March 4, 2021) A new study finds glyphosate use stimulates soil erosion responsible for releasing banned, toxic pesticide chlordecone (Kepone), which was used in banana production. For years, an unknown pollution source continuously contaminated water surrounding islands in the French West Indies (Martinique and Guadeloupe). However, researchers from the University of Savoie Mont Blanc in France have found that chlordecone—extensively used on banana farms from 1972 to 1993—is the contamination culprit.
Glyphosate is the most popular herbicide in the world, thus ubiquitous in the environment. Therefore, it is vital to understand the implication glyphosate use has on soil health and the potential re-release of soil-bound, toxic contaminants into the surrounding environment to safeguard human health. Researchers note, “[Chlordecone] fluxes drastically increased when glyphosate use began, leading to widespread ecosystem contamination. As glyphosate is used globally, ecotoxicological risk management strategies should consider how its application affects persistent pesticide storage in soils, transfer dynamics, and widespread contamination.”
Conventional pesticide use contaminates soil and their respective Critical Zone (CZ) compartments. These CZ compartments interact between the four main spheres (i.e., hydrosphere, biosphere, lithosphere, and atmosphere) of the Earth to support life. Recent decades demonstrate an increase in soil erosion due to sediment changes in critical zones results in “deforestation, overgrazing, tillage, and unsuitable agricultural practices with the use of herbicides.” Therefore, this study aims to evaluate the lack of understanding around long-term changes in soil from persistent pesticides.
Researchers collected core samples containing decades worth of soil sediment on the coast of French West Indies islands, using lead and cesium radionuclides (a naturally occurring unstable atom with excessive nuclear energy) to date sediment layers. To assess the presence of chlordecone, glyphosate, and their respective degradation products (i.e., chlordecone and aminomethylphosphonic acid) in samples, researchers used ALTHAUS 30 ultraperformance liquid chromatography system. Lastly, researchers ensured that all sediment originated from the land by comparing geochemical properties to existing island soil.
Study results demonstrate that glyphosate concentrations tripled in island soils upon a decrease in prices during 1997. In response, chlordecone concentration rose in surrounding waters. Researchers find, “…that the widespread use of a nonspecific systemic herbicide (glyphosate) since the late 1990s could be responsible for an unprecedented rise in soil erosion and downstream of a major release of remnant [chlordecone] pesticides trapped in banana field soils since their ban in the late 1990s’.”
Almost five decades of extensive glyphosate use has put animal, human, and environmental health at risk. The chemical’s ubiquity threatens 93 percent of all U.S. endangered species, with specific alterations on microbial gut composition and trophic cascades. Anthropomorphic (human) studies find a strong association between glyphosate exposure and the development of numerous health anomalies, including cancer, Parkinson’s disease, and autism. Furthermore, EPA’s 2019 decision to classify glyphosate herbicides as “not likely to be carcinogenic to humans—despite stark evidence demonstrating carcinogenicity—perpetuates environmental injustice among farmers, especially in marginalized communities. According to the Midwest Center for Investigative Reporting, a lawsuit—filed by the National Black Farmers Association against the chemical company Bayer/Monsanto—argues that Black farmers are, essentially, forced to use Roundup (glyphosate) and incur the risks of developing non-Hodgkin Lymphoma or other cancers (or health impacts) because of pesticide demands and the industry’s “grip” on U.S. agriculture. The suit maintains that Bayer/Monsanto knowingly failed, and continues to fail, to warn farmers adequately about the dangers of the pesticide.
Not only do health officials warn that continuous use of glyphosate will perpetuate adverse health effects, but that use also highlights recent concerns over antibiotic resistance. Glyphosate is patented as an antibiotic by agrochemical company Bayer/Monsanto as exposure hinders enzymatic pathways in many bacteria and parasites, serving as an antimicrobial. However, studies find glyphosate exposure disrupts the microbial composition in both soil and animals—including humans—discerningly eliminating beneficial bacteria while preserving unhealthy microbes. For instance, glyphosate kills bacterial species beneficial to humans and incorporated in probiotics, such as Lactobacillus, Bifidobacteria, and Enterococcal species, yet allows harmful bacteria E.coli, Clostridium perfringens and botulinum (progressively present autistic patients), and Salmonella to persist, leading to resistance. Similarly, glyphosate-exposed soils contain a greater abundance of genes associated with antibiotic resistance, as well as a higher number of inter-species transferable genetic material. Therefore, the use of antibiotics like glyphosate allows residues of antibiotics and antibiotic-resistant bacteria on agricultural lands to move through the environment, contaminate waterways, and ultimately reach consumers in food. Both human gut and contaminated waterways can promote antibiotic resistance, triggering longer-lasting infections, higher medical expenses, the need for more expensive or hazardous medications, and the inability to treat life-threatening illnesses.
The results of this study highlight an all too familiar issue regarding the re-release of stable, toxic, long-banned pesticides and the binding properties of pesticides to soils. Chlordecone, which has the tradename Kepone, is of specific concern due to its tumultuous history, resulting in a U.S. ban in 1976. However, following the ban, improper handling and dumping of Kepone into the James River (U.S.) led to extensive contamination, resulting in ever-present residues in sediments at the bottom of the river. Furthermore, existing aquatic organisms in the James river are still experiencing toxicity effects from the initial chlordecone disposal that caused a ban on regional fishing in the 1980s. In the case of this study, past misconceptions assuming chlordecone would bind to soil and remain immobile did not consider changes in soil property from external sources, including pesticides. Resembling the re-emergence of DDT from soil, the continuous use of glyphosate leaves soil bare and more susceptible to erosion from lack of organic material, altering the storage compartments of soil sediments from pesticide sinks to sources.
Although France banned chlordecone in 1990 over links to increased prostate cancer risk and premature births, Caribbean islands in the French West Indies continued to heavily use the toxic product—under government exemption—until 1993. Consequently, Indies Agricultural workers have been seeking justice for the French government’s failure to protect human health and limit chlordecone pollution on the islands. Considering researchers estimate chlordecone and other hazardous chemicals may persist in soil for several decades to centuries, it is essential to assess how continuous use of nutrient-stripping pesticides may contribute to the re-emergence of soil-bound chemicals in accumulated concentrations.
Researchers conclude, “Future studies of the environmental fate of pesticides in [critical zone] should take into account these potential pesticide–environment interactions from a long-term perspective. In terms of management options, reducing soil erosion on cropland by limiting herbicide treatments would lead to the growth of understory vegetation and ultimately result in the slower leaching of the pesticides stored in soils.”
Beyond Pesticides challenges the registration of chemicals like glyphosate in court due to their impacts on soil, air, water, and our health. While legal battles press on, the agricultural system should eliminate the use of toxic synthetic herbicides to avoid the myriad of problems they cause, especially regarding the re-release of soil-bound chemicals. Considering glyphosate levels in the human body reduce by 70% through a one-week switch to an organic diet, purchasing organic food whenever possible—which never allows glyphosate use—can help curb exposure and resulting adverse health effects.
Health and environmental advocates suggest the Biden administration halt the allowance of toxic agrochemicals to truly embrace a precautionary approach to pesticide use. Join Beyond Pesticides’ campaign for the good of all people and ecosystems. Tell Congress and the Biden Administration to clean up EPA and other federal agencies and end this era of corporate deception by restoring integrity to the scientific process. Consider becoming a member of Beyond Pesticides to help fight against chemical industry influence in our regulatory process.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Chemical & Engineering News, Environmental Science and Technology
Stop the poisoning of our children, animals, and environment
March 10th, 2021 at 3:45 pm