03
Jun
Plastic Coated Pesticides Adding to Soil and Ecosystem Contamination with Microplastics
(Beyond Pesticides, June 3, 2022) It is hardly news that plastics are a huge environmental problem, but three features of the plastic saturation of our planet are not well or widely recognized. One is the exacerbation of the climate emergency via emissions from the feedstocks for, and production and use of, plastics. Another is that proffered in a late 2021 report by the Food and Agriculture Organization of the United Nations: “the land we use to grow our food is contaminated with even larger quantities of plastic pollutants” than the well-publicized amount of plastics in our oceans. The third is the little-known issue of the plastic coating of some synthetic pesticides and fertilizers, as investigated by a recent report from the Center for International Environmental Law (CIEL). Beyond Pesticides has written about the “contributions” of plastics to the climate crisis, as well as issues related to uses of plastics in organic agriculture and the scourge of chemically intensive farming.
An enormous amount of plastic in thousands of forms is produced globally each year. Toxic plastic pollution is now found, as The Guardian puts it, “from the summit of Mount Everest to the deepest oceans.” A frequently cited and chilling metric is this: the total mass of plastics on Earth now exceeds the total mass of all living mammals. How did we get here?
With the chemical “boom” years during and following World War II, the invention, and industrial, defense, medical, and consumer applications of synthetic polymers grew robustly in the U.S. These materials seemed remarkable in the early, pre-war and WWII years — strong, flexible, lightweight, resistive, easy to mass produce, and chemically inert. As Beyond Pesticides wrote earlier in 2022, “during the war, U.S. plastic production increased by 300%. The plastic surge continued throughout the rest of the 20th century, and is unabated today [although much of the production has shifted to Asia]. Indeed, 2020 estimates clocked the amount of plastic in the world at roughly 8.3 billion tons — with 6.3 billion of those tons being ‘trashed’ plastic. As the UNEP (United Nations Environment Programme) invites us to consider: ‘Imagine 55 million jumbo jets and that’s how much plastic exists.’”
The “chemically inert” property of plastics has proved supremely problematic, in part because it turns out that under some conditions, many plastics are actually not inert, but can and do leach toxic chemicals into their surrounds. Also, plastics do not break down chemically into their constituent compounds, and because plastics are synthetic materials, they cannot exist “benignly” in nature after their useful lives. In addition, the “inert” quality is causing massive damage to environments and organisms because, centrally, plastics can break down only mechanically, into smaller and smaller bits until, as “microplastics” — pieces less than five millimeters in diameter — they mobilize and travel everywhere.
Microplastics have suffused every ecosystem on the planet (including the heights of Everest, the depths of the oceans, and Antarctica), and have entered the food chain, atop which humans sit. Thus, they are now in marine organisms, terrestrial livestock, and human bodies (bloodstream, placentas, lungs, feces). Microplastics are in our drinking water and in the soils that grow our food. Humans are inhaling and ingesting plastics — and whatever toxins they may contain — through multiple exposure routes.
Multiple research efforts have identified the role of plastics in the entropic climate trajectory along which the fossil fuel industry has driven the globe. Carbon and methane are the two primary actors in human causation of the warming of the Earth’s atmosphere. The Environmental Defense Fund has notes that “at least 25% of today’s warming is driven by methane from human actions. One of the largest methane sources is the oil and gas industry.”
Beyond Pesticides has explained that this hegemonic industry provides the petrochemical feedstocks for the production of plastics, as well as of synthetic fertilizers and pesticides. Worse, as the industry is more often and more vociferously called out for its role in the climate crisis, it has come to view plastics (and fertilizers and pesticides) as important future markets for its petrochemical products, and is creating facilities geared for that future.
The Executive Summary for the 2019 report, Plastic & Climate: The Hidden Costs of a Plastic Planet, asserts that plastic pollution is “not only destroying the environment and endangering human health, but also, undermining efforts to reduce carbon pollution and prevent climate catastrophe. . . . Nearly every piece of plastic begins as a fossil fuel, and greenhouse gases are emitted at each of each stage of the plastic lifecycle: 1) fossil fuel extraction and transport, 2) plastic refining and manufacture, 3) managing plastic waste, and 4) plastic’s ongoing impact once it reaches our oceans, waterways, and landscape. . . . At current levels, greenhouse gas emissions from the plastic lifecycle threaten the ability of the global community to keep . . . temperature rise below 1.5°C. With the petrochemical and plastic industries planning a massive expansion in production, the problem is on track to get much worse.”
The particular roles and magnitude of plastic use and pollution in agriculture have generally received little public or advocacy attention, but they certainly merit it. Plastics are used in agricultural production, by associated value chains, and in food packaging. Farmers use plastic for sheet mulches, netting, tree guards, plant containers, irrigation tubing, feed bags, and many other items, to the tune of roughly 816 million pounds annually in the U.S. Plastic sheet mulches account for 126 million of those pounds, and plastic containers for another 422 million — one third of all that in Florida alone. There are no policies in the U.S. that require or encourage recycling of agricultural plastics.
Plastic mulching films have become, over the past couple of decades, an extremely popular product for use on crops to suppress weeds, increase soil temperatures, reduce moisture loss from surface evaporation, and reduce nutrient runoff due to heavy rains. These mulch products are commonly produced from LDPE (low-density polyethylene) or synthetic polymers, including PVC (polyvinyl chloride, a particularly nasty material that releases carcinogenic dioxins when produced or burned). Farmers increasingly rely on such synthetic mulching films rather than on traditional materials such as cover crops, composted manures, straw, and others.
For all their utility to producers, these huge sheets of mulching film are creating more environmental havoc. After sitting on the soil for a season, they often have been damaged by farmworkers’ tools or motorized farm equipment; acquire clinging globs of soil and plant residue; and are further degraded by effects of sunlight, water, and wind, causing some tearing and mechanical breakdown that ends up contaminating agricultural soils with microplastics. Indeed, the 2021 FAO report indicates that there is more microplastic pollution in soils than in the oceans.
In addition, even if farmers try to recycle these plastic mulching sheets (and facilities that can do so are not especially common), the sheets are often so fragmented that they are difficult to retrieve post-harvest, and recycling them becomes nearly impossible. Typically, this mulching film is pulled up, leaving plenty of microplastics behind, and either burned in the field — releasing greenhouse gas (GHG) emissions and toxic compounds into the air — or dumped eventually into landfills.
Ohio’s Country Journal noted in a 2020 article that “the plastic left in the soil is changing the soil environment. At first, the remnants in the soil were a nuisance, clogging farm equipment, blowing in the wind, getting caught on fencing and washing into ditches. Now, more than 20 years of plastic building up in the soil has started to interfere with roots and water movement, reducing crop yield and canceling out some of the benefits of the plastic mulch.”
The FAO report makes recommendations, chief among which is to return to one of the “alternatives” — which are actually entirely traditional — organic mulch materials, cover crops, and other methods that are largely what organic farmers use. The co-benefits of these practices include savings on inputs, avoidance of the GHGs embedded in plastic production and disposal, incorporation of carbon-holding biomass into the soil, yielding long-term improvements in soil health, and when coupled with organic, non-chemical management (no synthetic pesticides or fertilizers), potential access to premium markets. The report also recommends avoiding petrochemical plastic use, banning of toxic PVC for these materials, and increasing the thickness of mulching sheets so as to make them less likely to degrade in the field.
There are other kinds of alternatives, such as so-called “bioplastic” mulching film, made from the starches in corn, soy, wheat, or sugarcane. Manufacturers of these promote them as biodegradable, i.e., capable of breaking down and being incorporated into the soil after harvest. However, the decomposition of such plastics in different soils and climatic conditions varies widely, and the long-term impact on soils of the use of biodegradable mulch films is not well understood. A genuinely biodegradable mulch film that breaks down adequately, is readily decomposed by soil microbes, and has no deleterious impacts on soil or those microorganisms, is not yet a reality.
In the U.S. Department of Agriculture’s (USDA’s) National Organics Program (NOP), the issue of plastic mulches has been a controversial one since biodegradable biobased mulch film (BBMF) was first added to the NOP National List of Allowed and Prohibited Substances in 2014. Beyond Pesticides, which has been active in advocating for the integrity and strength of the National Organic Standards (NOS), has repeatedly weighed in on the issue. (See our Keeping Organic Strong webpage for an orientation to these issues.)
In its most-recent (2021) missive to the National Organic Standards Board (NOSB), Beyond Pesticides wrote: “While BBMF was supported enthusiastically by those who saw an opportunity to have the benefits of plastic mulch without the wasteful and labor-intensive practice of carting it off to the landfill at the end of every growing season, others . . . warned that the available products were ‘not ready for prime time.’ As predicted, the Organic Materials Research Institute (OMRI) soon announced that no products met the criteria in the National List — that is, 100% biobased and biodegradable.”
In addition to the inadequate character of the available products — which per se fail to meet NOSB requirements — Beyond Pesticides’ testimony identified other problems with their deployment. “BBMFs are not removed from the field by the grower. Instead, they are tilled into the soil. The tillage process purposefully creates microplastics, with the intention that the action of soil organisms will degrade these small particles. However, as reported in OMRI’s 2016 Supplemental Technical Review, many growers report that fragments persist in the soil. OMRI reports that research on the eventual fate of biodegradable mulch films is ongoing. There is, nevertheless, research reported by OMRI indicating that the BBMFs do not completely degrade and may degrade more slowly when tilled under the surface, that they contain components that may be hazardous, and particles may adsorb persistent toxins.”
Beyond Pesticides affirms that synthetic mulches should not replace organic mulches in the National List, noting that organic mulches have long been a hallmark of organic production. It justifies this position on the basis of the NOSB Principles of Organic Production and Handling, which state: “Organic agriculture is an ecological production management system that promotes and enhances biodiversity, biological cycles, and soil biological activity. It emphasizes the use of management practices in preference to the use of off-farm inputs, taking into account that regional conditions require locally adapted systems. These goals are met, where possible, through the use of cultural, biological, and mechanical methods, as opposed to using synthetic materials to fulfill specific functions within the system.”
The use of plastics in coating pesticides and fertilizers, purportedly to allow for controlled release of chemicals or nutrients, is an additional and alarming branch of global petrochemical saturation. (Beyond Pesticides is compelled to note that organic fertilizers, by their nature, provide “controlled release” nutrition without all the toxic downsides of synthetic fertilizers coated in polymers.) In addition, agrochemical companies add microplastics to synthetic fertilizers (e.g., as anti-caking agents), proffer them as soil conditioners, and coat some seeds with polymers.
The CIEL report, Sowing a Plastic Planet: How Microplastics in Agrochemicals Are Affecting Our Soils, Our Food, and Our Future, dives deep into the many issues around microplastics, including the coating, or “encapsulation,” of pesticides and fertilizers. It notes that agriculture is one of the largest users of products with intentionally added microplastics, and that this use is rising (11% growth is projected for 2018 to 2025). Microplastics remain in the soil long after the encapsulation’s function — slow release — ends, polluting the soil and readily dispersing into the air or water.
The report clarifies that this application of “plastic-coated agrochemicals to soils and crops directly introduces microplastic into the environment and potentially into the food supply. It also compounds the health and environmental hazards posed by agrochemicals themselves. . . . Synthetic fertilizers and pesticides, derived primarily from oil- and gas-based feedstocks, are already some of the most toxic substances in use today. Encapsulating them in microplastic, itself fossil fuel in another form, only heightens the risks. Because of its deliberate and controlled nature, microplastic pollution from plastic-coated agrochemicals is especially egregious, but it is also readily preventable. The only barriers are public awareness of the problem and political will to tackle it at its source by regulating the plastics industry.”
Though encapsulation is not a new technology, industry’s promotion of its use in synthetic pesticides and fertilizers has taken a perverse turn — to greenwashing these products as “planet-safe” choices. The CIEL report asserts that the “repackaging” of this microplastic technology in this context sometimes involves no mention of “plastics,” but instead, use of less well-known and poorly understood terms, such as “polymer,” in describing the coating material. Further, “plastic encapsulation may be portrayed as a plus for the environment. Agrochemical industry marketing and messaging around controlled-release products emphasizes the technology’s purported efficiency as a key to more sustainable farming.”
The report concludes: “Plastic-coated fertilizers and pesticides are not only dangerous, but also unnecessary, because effective alternatives exist. There are a multitude of strategies for reducing the use of synthetic pesticides and fertilizers, including high-performing agroecological techniques that do not rely on fossil fuel-based agrochemical inputs at all.”
Beyond Pesticides agrees, and reiterates that organic regenerative approaches to agriculture are the solution, and beat out chemical approaches on virtually every front: safety for humans, organisms, and the environment; soil health; a nutritive food supply; and even yields and economics, in many cases. Use of chemical pesticides to achieve agricultural and other goals is by nature a dead end, both because these compounds cause great and broad damage, and because resistance inevitably develops over time, rendering them ineffective — to which industry responds with new, additional, and potentially more harmful, formulations.
Making the transition to non-chemical management in farming, turf care, and other maintenance and protection protocols is beyond urgent. The chemical — and plastic — ubiquity in our materials stream, environment, food, and bodies, coupled with the climate emergency (and the enormous catalysis of it by the petro- and agrochemical industries) threaten every single thing humans value. Join Beyond Pesticides in advocating for the protection of our world from the risks imposed by these industries.
Sources: https://www.fao.org/3/cb7856en/cb7856en.pdf and https://www.ciel.org/reports/microplastics-in-agrochemicals/
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
