How Agriculture Became a Pollution Pipeline Into Our Food

When we tend to picture plastic pollution, we usually imagine bottles on beaches and sea turtles tangled in nets. But some of the worst plastic contamination on Earth is sitting in the dirt beneath our crops. Farmland soils now contain more microplastics than the ocean, according to the UN Food and Agriculture Organization, and the problem is only getting worse. Once these plastics enter the soil, they never really escape, causing detrimental impacts to our agricultural ecosystem and our health.

A Field Full of Plastic

Farms around the world used roughly 12.5 million tonnes of plastic in 2019, a number projected to grow by 50% between 2018 and 2030. Plastics on farms are used in things like seed trays and irrigation lines, and for producing mulch and seed coatings. 

The issue is that as plastics break down, they become tiny particles known as microplastics, which end up everywhere. Microplastics and the chemicals inside them have also increasingly contaminated our water sources. Sewage sludge (also called biosolids) applied as fertilizer, reclaimed wastewater used for irrigation, and even compost and manure can also carry plastic fragments when the plastics in them aren’t properly filtered out first. 

Fertilizer can also carry synthetic polymers. Controlled-release fertilizers seal nutrients inside a thin plastic shell that breaks down slowly and persists in the soil. In some places, microplastics have been shown to accumulate after a decade of continuous fertilizer use. 

What Plastic Does to the Soil and the Plants

Microplastics aren’t doing anything in the dirt. In agricultural soils, they clog the tiny air and water channels that plant roots depend on; they alter water retention, and they throw off the balance of bacteria and fungi that keep soil fertile. The microplastics also leach chemicals such as phthalates and bisphenol A (BPA) into the ground because these chemicals aren’t bound to the polymer. 

Most concerning, the contamination doesn’t stop at the soil. Research now shows that the smallest fragments, nanoplastics, can be absorbed by plant roots and carried into shoots, leaves, and edible parts of crops. In one case, plastic fibers at concentration levels found in biosolids reduced tomato shoot length by 67% and root growth by 82%. 

After the Farm

Plastic doesn’t just end up in agricultural land. Plastics are wrapped around the food itself, often multiple times before it ever reaches a shelf. Food packaging in agricultural value chains accounts for roughly 37.3 million tonnes of plastics annually, and most of it is designed to be discarded after a single use.  

Plastics continue to get into our food after the farm; researchers have found microplastics in fruits, vegetables, meat, fish, and milk. High-friction or high-volume food processing equipment can shed microplastics from its plastic components, and materials that come into direct contact with food such as plastic wrap, single-use packaging and containers, and plastic lids, liners, and coatings also shed plastics into food. 

Even at home, microplastics from cookware can contaminate our food. And if you use a microwave to heat food in a plastic container, you’re increasing the chance for chemicals from microplastics to leach directly into the food.

Protecting Our Food from Plastics

Solutions are within reach, but require coordinated action. We need research into what these persistent chemicals actually do once they are in agricultural materials. We also need tighter regulation of microplastic contamination in water, and federally set limits on PFAS and biosolid contamination. Alternatives to plastic and synthetic fertilizers exist too, such as biodegradable films, mechanical mulching, and regenerative practices that rebuild soil health without synthetic inputs. 

The catch is that regenerative practices and biodegradable alternatives cost more up front, and stakeholders like farmers who are already dealing with contamination risk have to shoulder those extra costs. A real solution should cover the gap.

Farmers and farmworkers should be active partners in efforts to remove plastics from our food system. Indigenous communities, whose stewardship traditions exemplify the regenerative practices needed, must be included in these discussions. Agricultural agencies and universities should support region-specific policy through testing, monitoring, and scientific research.

The plastic in our food system didn’t get there by accident, and it won’t leave that way either; only real investment, collaboration, and accountability will get it out.

To learn more about how you can avoid exposure to plastics, visit our End Plastics page, or take a pledge to remove one kind of plastic from your life!