(Beyond pesticides, March 4, 2021) A new study finds that the use of glyphosate stimulates soil erosion, responsible for the release of the banned toxic pesticide, chlordecone (Kepone), used in banana production. For years, an unknown source of pollution has permanently contaminated the surrounding waters of the islands of the French Antilles (Martinique and Guadeloupe). However, researchers at the University of Savoie Mont Blanc in France have found that chlordecone – widely used in banana plantations from 1972 to 1993 – is the source of the contamination.
Glyphosate is the world’s most popular herbicide and is therefore ubiquitous in the environment. Therefore, understanding the implications of glyphosate use on soil health and the potential re-emission of toxic soil-related contaminants into the surrounding environment is essential to protect human health. The researchers note: “[Chlordecone] fluxes increased dramatically when glyphosate use began, leading to widespread contamination of ecosystems. Since glyphosate is used worldwide, ecotoxicological risk management strategies should consider how its application affects the persistent storage of pesticides in soils, transfer dynamics and widespread contamination. “
The conventional use of pesticides contaminates the soil and their respective compartments of the critical zone (CZ). These compartments of CZ interact between the four major spheres (i.e. hydrosphere, biosphere, lithosphere and atmosphere) of Earth to support life. The last decades show that an increase in soil erosion due to changes in sediment in critical areas leads to “deforestation, overgrazing, tillage and inappropriate agricultural practices with the use of herbicides”. Therefore, this study aims to assess the lack of understanding of long-term changes in soil due to persistent pesticides.
Researchers collected cores containing decades of soil sediment off the coast of the French West Indies, using radionuclides of lead and cesium (a naturally occurring unstable atom with excessive nuclear energy) to date the sediment layers. To assess the presence of chlordecone, glyphosate and their respective degradation products (i.e., chlordecone and aminomethylphosphonic acid) in the samples, the researchers used the ALTHAUS 30 ultra-performance liquid chromatography system. ensured that all sediment came from the land by comparing the geochemical properties to the existing island soil.
The results of the study show that concentrations of glyphosate tripled in island soils when prices declined in 1997. In response, the concentration of chlordecone increased in surrounding waters. The researchers find, “… that the widespread use of a non-specific systemic herbicide (glyphosate) since the late 1990s could be responsible for an unprecedented increase in soil erosion and downstream a significant release. of residue. [chlordecone] pesticides trapped in the soil of banana plantations since their ban at the end of the 1990s ”.
Almost five decades of intensive use of glyphosate has endangered animal, human and environmental health. The ubiquity of the chemical threatens 93% of all endangered species in the United States, with specific alterations in the microbial composition of the gut and trophic cascades. Anthropomorphic (human) studies show a strong association between glyphosate exposure and the development of many health abnormalities, including cancer, Parkinson’s disease and autism. Additionally, the 2019 EPA decision to classify glyphosate herbicides as “not likely to be carcinogenic to humans – despite overwhelming evidence demonstrating carcinogenicity – perpetuates environmental injustice among farmers, by especially in marginalized communities. According to 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, in essence, forced to use Roundup (glyphosate) and run the risk of developing non-Hodgkin lymphoma or other cancers (or health effects) due to the demand for pesticides and the industry’s “grip” on American agriculture. The lawsuit argues that Bayer / Monsanto knowingly failed, and continues to fail, to adequately warn farmers of the dangers of the pesticide.
Not only are health officials warning that continued use of glyphosate will perpetuate adverse health effects, but that use also highlights recent concerns about antibiotic resistance. Glyphosate is patented as an antibiotic by the agrochemical company Bayer / Monsanto because the exposure hinders the enzymatic pathways of many bacteria and parasites, serving as an antimicrobial. However, studies show that exposure to glyphosate disrupts microbial makeup in both soil and animals – including humans – discerningly eliminating beneficial bacteria while preserving unhealthy microbes. For example, glyphosate kills bacterial species beneficial to humans and incorporated into probiotics, such as Lactobacillus, bifidobacteria, and Enterococcus species, but allows harmful bacteria E. coli, Clostridium perfringens and botulinum (progressively present autistic patients) and Salmonella persist, leading to resistance. Likewise, soils exposed to glyphosate contain a greater abundance of genes associated with antibiotic resistance, as well as a greater number of transferable genetic material between species. Therefore, the use of antibiotics like glyphosate allows residues of antibiotics and antibiotic resistant bacteria on farmland to move through the environment, contaminate waterways and ultimately reach food consumers. Human gut and contaminated waterways can promote resistance to antibiotics, triggering long-lasting infections, higher medical costs, the need for more expensive or more dangerous drugs, and the inability to treat life-threatening illnesses .
The results of this study highlight an all too familiar question regarding the re-release of stable, toxic and long-banned pesticides and the binding properties of pesticides to soils. Chlordecone, which goes by the brand name Kepone, is of particular concern because of its tumultuous history, which culminated in an American ban in 1976. However, as a result of this ban, improper handling and spillage of Kepone in the James River (USA) led to significant contamination, resulting in ubiquitous residues in the sediment at the bottom of the river. In addition, existing aquatic organisms in the James River are still experiencing toxic effects following the initial elimination of chlordecone which resulted in a regional fishing ban in the 1980s. In the case of this study, the misconceptions of the past assuming that chlordecone would bind to soil and remain immobile did not account for changes in soil properties from external sources, including pesticides. Resembling the re-emergence of DDT from soil, continued use of glyphosate leaves soil bare and more susceptible to erosion through lack of organic matter, altering soil sediment storage compartments from pesticide wells to springs.
Although France banned chlordecone in 1990 because of its links to an increased risk of prostate cancer and premature births, the Caribbean islands in the French Antilles continued to use the toxic product heavily – under government exemption – until 1993. As a result, agricultural workers in India demanded justice for the failure of the French government to protect human health and limit chlordecone pollution in the islands. Given that researchers believe that chlordecone and other dangerous chemicals can persist in soil for decades to centuries, it is critical to assess how continued use of nutrient-stripping pesticides may contribute to the re-emergence of soil-bound chemicals in accumulated concentrations.
The researchers conclude: “Future studies on 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 lead to slower leaching of stored pesticides. the grounds.
Beyond Pesticides is challenging the registration of chemicals like glyphosate in court because of their impacts on soil, air, water and our health. As legal battles continue, the farming system should eliminate the use of toxic synthetic herbicides to avoid the myriad of problems they pose, especially with the re-release of soil-bound chemicals. Since glyphosate levels in the human body drop by 70% through a week’s switch to an organic diet, buying organic foods as much as possible – which never allows the use of glyphosate – can help reduce exposure and resulting adverse health effects.
Health and environmental advocates suggest that the Biden administration stop allocating toxic agrochemicals to truly take a precautionary approach to pesticide use. Join the Beyond Pesticides campaign for the benefit of all people and all ecosystems. Tell Congress and the Biden administration to clean up the EPA and other federal agencies and end this era of corporate deception by restoring the integrity of the scientific process. Consider becoming a member of Beyond Pesticides to help combat the influence of the chemical industry in our regulatory process.
All positions and opinions not attributed in this article are those of Beyond Pesticides.
Source: Chemistry and Engineering News, Environmental science and technology