By Alastair Bland
I first tuned in to murmurs about plastic pollution in the late 1980s, when my mom would send me and my siblings to school with lunches packed in brown paper bags and wax-based sandwich wrappers. Compostable was in, and plastic bags out. I embraced her disdain, and for decades to come I would use whatever means possible to avoid plastic produce bags while shopping. By carrying home dinner in a canvas bag or even my bike helmet, I cultivated the illusion that I had cleared a plastic-free pathway from farm to table.
But I’d overlooked the farm itself, and as it turns out the fields that grow our food are filthy with plastic waste — the direct result of modern farming’s increasing reliance on the signature material of the Anthropocene. Whether incidentally littered onsite or directly diffused into the soil via polymer-coated chemical pellets, plastic is now embedded both in agricultural practices and the tilled earth itself. It leaks into waterways, might be poisoning our food, and is virtually unregulated.
Nobody knows what to do about it.
“Now we have it, and it’s the devil … it’s a global menace,” says Tom Willey, a retired certified organic farmer in the San Joaquin Valley who reluctantly used plastic sheet “mulch” for about 20 years ago on his farm near Madera.
The agricultural use of plastic film is especially prevalent in the strawberry fields of California’s Central Coast region, but it occurs just about everywhere food is grown. From Modesto to Manteca, from Davis to Petaluma, and throughout the Delta and North Bay regions, plastic sheeting for hoop-style greenhouses and groundcovers are seen in fields beside public roads and waterways, sometimes strewn in windblown rags and tatters, waiting for disposal.
Though unsightly and potentially harmful, plastic has just about everything else going for it. Flexible, strong, and dirt-cheap, plastic is used in many standard farming applications, including irrigation tubing or “tape,” film for hoop houses and ground covers, and uncountable plastic pots, clips, ties, tags, and labels. Sludge from wastewater treatment plants, rich with microplastic pollution, is applied as fertilizer on many conventional farms, intensifying plastic buildup in soils. Perhaps most alarming is the widespread use of microplastic coatings on fertilizer and pesticide granules — a practice international organizations want to see banned.
It all adds up. An analysis from the California Marine Sanctuary Foundation estimated that fields in Monterey County alone collectively use 10,000 tons of plastic annually — especially disposable drip irrigation tubing and plastic film, which are often bulldozed into heaps following each harvest. The same materials are used globally, and across the world farmers use roughly 13 million tons of plastic each year, according to a United Nations Food and Agriculture Organization report.
Nitty Gritty News from the Field
Though farm plastic amounts to less than five percent of all plastic production — now approaching half a billion tons annually — its use on farms is concerning for several reasons, including its proximity to food supplies and to farmworkers. There is evidence, too, that microplastic pollution can decrease long-term fertility of soil and its ability to cling to water. All of which make worse findings that microplastic buildup is happening many times more rapidly in soils than in the ocean.
In a white paper published in March, UC Davis researchers Donald Bruun and Pamela Lein discussed, among other concerns about ag plastic, the findings of a study on radishes. Alarmingly, the presence of microplastic in the soil was correlated to the transfer of a potent insecticide, chlorpyrifos — a controversial insect poison linked to disrupted human brain development and banned in many countries — into the edible roots themselves.
Ecotoxicologist Susanne Brander, an associate professor at Oregon State University, says some pesticides are very hydrophobic, meaning “they’re going to associate with anything that’s as far away from water as possible.” In many farm fields, that might mean the chemicals adsorb to plastic pieces and, over time, become hyperconcentrated in the soil — contrary to intuitive logic that water should wash these compounds away. If the plastic is finding its way into crops and livestock — both documented contamination pathways — the chemical will go with it.
Broken and shredded plastic pieces readily escape from farms into the wider environment, too. In the Monterey County study, Pamela Krone, the Marine Sanctuary Foundation’s water quality program manager, surveyed streams and rivers draining the region’s farmland and found high concentrations of scraps identifiable as farm-based plastic littered on banks and snagged in riparian brush.
Unfortunately, plastic’s near-term benefits on farms make it indispensable for growers. It’s as cheap as it is versatile, and in its many forms, it ultimately means more food produced, using less money and fewer inputs, per unit of land.
“It’s all about numbers, it’s all about money,” Willey says. “No one’s in love with plastics.”
Willey says he was philosophically opposed to using plastic on his farm long before the issue became a trending media topic. For about 20 years he made do without plastic sheet mulch. Then, at the insistence of a conventional farmer friend, Willey reluctantly gave polyethylene film a try around the turn of this century. United States organic regulations, after all, allow the use of plastic sheeting as long as it is thoroughly removed from the field after use.
“It was miraculous,” he recalls, explaining that the plastic sheeting helped protect vegetables from insects and mold, preserved moisture in the root zone, helped concentrate fertilizers for better growth, and provided “beautiful, perfect weed control.”
Willey says it was once economically feasible for small-scale farmers to use straw or woodchip mulches that protect fruits like berries from the bare soil. But in modern systems of large farms and low profit margins, plastic sheet mulch is the only viable option. One obstacle against ditching plastic now, Willy explains, is that markets have been conditioned for cheap food, which plastic helps make widely available.
Biodegradable substitutes are a holy grail in the rally for a breakaway from plastic, but in the agriculture sector, where materials are exposed to wind, water, and sun, such alternatives have proven substandard. For instance, some Central Coast farmers have experimented with biodegradable mulch film, but Krone says they found it broke down too slowly to make tilling it into the soil or composting it a workable option.
Willey tried it out, too, with similar results. “It either broke down too slowly, or too quickly,” he says.
Though plastic is becoming increasingly controversial and has undebated impacts to the environment, its use in farming — often termed “plasticulture” — continues to increase rapidly, and no one knows quite what to do about it. “It’s like we’re on a treadmill, and we can’t get off,” Krone says.
Never Too Late for Source Control
While farm fields slip under the radar, the ocean has gained global attention for the plastic pollution burden it carries. Half of all plastic ever made has been produced since the year 2000, spilling an estimated 12 million tons of plastic into the ocean each year at the latest calculation. This rate of pollution could double or triple by 2030.
All the while, plastic debris is growing smaller, and smaller, and smaller — an unstoppable breakdown process that researchers and media have chased with innovations in vocabulary. In 2004, when a six-pack soda holster wrapped around a bird’s neck was still the poster image of about the worst ocean plastic could do, researchers, observing a disconcerting trend, coined the term “microplastic.” “Nanoplastic” followed.
Scientists estimated last year that the ocean’s surface waters contain 171 trillion pieces of small plastic. Adrift at sea, this debris enters the food web from all directions. The biggest creatures in the ocean eat plastic, and so do some of the smallest, like krill and plankton — a food web disruption that researchers warn could accelerate ocean oxygen loss.
Biologist and research diver Tristin Anoush McHugh now finds plastic inside sea urchins, which she collects and samples as part of her kelp restoration work with The Nature Conservancy. It was three years ago, she recalls, that she began spotting tiny bits of purple, red, and blue in the animals’ digestive tracts. “We were like, ‘This is not an organic compound — this can’t be anything other than microplastic,’” she says.
Even if we stopped all plastic production today, these tiny particles would remain in the water for generations. “Once micro- and nanoplastics are in the ocean, there is essentially no way to get them back,” says Anja Brandon, Ocean Conservancy’s associate director of U.S. Plastics Policy.
So intractable, in fact, is this pollution crisis that policy pushers feel it’s not worth focusing on. “We have to be looking upstream,” says Darcy Bradley, a lead scientist with The Nature Conservancy’s California Oceans Program. “If we’re only looking at the ocean, it’s too late.”
Preventing plastic pollution in the first place is the key — including from farms. A 2021 study in Science of the Total Environment showed that soils prone to erosion readily transfer microplastics into waterways. In a striking parallel, other research has shown fishing gear to be the main source of the ocean’s large plastic debris.
Advocates are also casting nets farther upstream to regulate plastic production, though with limited success. Global negotiations to cap plastic production got underway in April in Ottawa, two years after 175 nations signed an agreement to end plastic pollution. The goal is to have a plan ready this year.
Also in 2022, California passed SB 54, aimed at reducing single-use plastic waste within the next decade. Another proposed state law recently tripped and fell at the finish line: AB 1628 would have required filters on washing machines to catch the millions of microplastic fibers that may be expelled from a single load of laundry. Gov. Gavin Newsom vetoed it in October. (France has passed such a rule.)
SB 54 requires a 25% reduction by 2032 of plastic packaging and plastic food wrappers and containers sold in California. This sector of the plastic waste inventory amounts to 40% of all plastic waste globally, according to Brandon, who helped draft the legislation. “So it’s a big piece of the pie,” she says.
While a 25% cut in this portion of the waste stream does not keep pace with the global escalation of plastic production, Bradley says it is, in fact, a rapid pace in the scheme of policy making. Anyway, moving too rapidly could backfire. “It’s really important in target setting that we set targets that are truly ambitious and … also achievable,” she says. “If it’s not achievable, no one will sign up to do it.”
Unhealthy Hidden Costs
Cost has also proven to be an obstacle against reducing plastic use and one of the strongest motivators to continue using it. When Newsom vetoed the proposal to require microplastic filters on washing machines, he said in a statement that the rule would impose unreasonable costs on consumers (who might buy a new washing machine once every couple of decades). Business interests tend to oppose restrictions on plastic bags for similarly myopic reasons. And when it comes to farming, plastic is favored because, as Brandon at Ocean Conservancy says, it “is dangerously cheap.”
Or so it appears. While plastic helps cut farm and industry costs, the impacts of plastic pollution spill across the planet, affecting everyone. Revenue and time is spent on cleanups, animal rescues, and, probably, increased healthcare expenses.
“There’s a huge externalized cost that’s not accounted for, and if it was accounted for, perhaps we’d be willing to pay more for food,” Krone, at the Marine Sanctuary Foundation, says.
A team of researchers published findings in March that the chemicals used in plastic production caused about $250 billion in healthcare costs in the United States in 2018. The study indicated no ambiguity over plastic pollution’s health impacts — until recently a hotly contested field.
Brander recalls common refrains from industry and lobbyists just a few years ago: “From the people pushing back at the need for more research and the need to regulate microplastics, the response was always, ‘We need more data.’ Now, I feel like we have those data.”
But for the industries that profit off plastic production, a variety of factors play in their favor. For example, impacts of ambient pollution tend to arrive years after exposure. This makes it difficult, if not impossible, to hold polluters accountable. While agricultural plastic use amounts in many cases to willful pollution by industry, regulators and society at large tend to ignore it thanks to the out-of-sight, out-of-mind nature of microplastics buried in a farm field.
This leads consumers to focus on immediate conveniences and gratification. “That short-term benefit [of a product] outweighs the long-term potential negative consequence of getting cancer when we turn 55, or younger,” Brander says, adding that many chemicals associated with microplastics are known potential carcinogens. Others are endocrine disruptors, and a recent study found microplastic buildup in arteries is correlated with increased risk of cardiovascular disease.
The insidious encroachment of plastic into our environment has caught us off guard. Now, like soldiers who spot the enemy only after they’re surrounded, humans must reckon with the irreversible fallout of the plastic boom, whether that’s rising development disorders, more dementia, or increasing cancer rates. With time, we will know what we’re in for.
In spite of commitments to reduce plastic use, production is increasing exponentially. It has doubled since 2000 and could triple by 2060, at which point experts guess the world will have produced 40 billion tons of the stuff since industrial-scale plastic production began in the 1940s. As little as 9 percent of plastic gets recycled; the rest, according to estimates, is incinerated, buried, or discarded into the environment.
“It’s genuinely scary,” says Brandon, who argues that consumers need more options for buying products that are plastic free.
Legislation and international coordination may be the best tools available, but meaningful action is dragging. Federal agencies, Brander says, are slow to fund research on microplastics, and even the Clean Water Act, she says, lacks the leverage to regulate the particles. “[The solution] really needs to be a systemic change. We can’t put this on the backs of consumers to solve.”
This story was produced by Estuary News Group with funding from the Delta Stewardship Council.
