The Ground Beneath Our Feet Is Poisoned, And We Put it There.

Dhaani Jeevanani  | Aug 2026 | 5 min read

You've probably heard the microplastics conversation before. Tiny bits of plastic, floating around in the ocean, being eaten by fish. It's a problem, a big one, and I covered it in Microplastics: A Silent Poison. But here's the thing: while we've been staring at the water, an equally alarming story has been unfolding right under our feet.

Microplastics are in the soil. The dirt we grow our food in. And unlike the ocean,  where at least it's hard to ignore a plastic bottle washing up on the beach,  this crisis is completely invisible.

Terrestrial environments may contain up to 20 times more plastic than oceanic systems.

Twenty times.

Let that number breathe for a second. We've spent years rallying around ocean plastic. Documentaries, hashtags, paper straws. And the whole time, the land had it 20 times worse. So let's talk about it.

How Does Plastic Even Get Into Soil?

This was the first thing I wanted to understand. Soil isn't a river. Plastic doesn't just flow into it. So how exactly does this happen? Turns out, there are more ways than you'd think, and most of them are things we barely even notice.

1. Plastic Mulch Films on Farms

Farmers use thin plastic sheeting to cover soil: it keeps moisture in, controls weeds, and boosts crop yields. Sounds useful, right? The problem is that these films degrade over time and break apart directly into the farmland they were supposed to protect. This is the single biggest pathway for microplastics into agricultural soil, especially in drier regions.

2. Sewage Sludge Used as Fertilizer

Wastewater treatment plants generate a byproduct called sewage sludge, and it gets spread on agricultural fields as fertilizer. The problem? That sludge is loaded with microplastics from everything that went down our drains: laundry lint from synthetic fabrics, microbeads from face wash, tire rubber particles washed off roads. Researchers identify this as one of the main causes of soil pollution in farmland worldwide.

3. It Literally Rains Down From the Sky

I was not prepared for this one. Wind picks up microplastics, from tire wear on roads, from laundry lint, from degrading plastic trash, and carries them through the atmosphere across entire continents. They then fall back down as what scientists call "plastic rain."

Wild fact: tire wear alone accounts for nearly a third of all airborne plastic particles. Every time a car drives, it sheds microscopic rubber into the air, and those particles eventually land on soil, including farmland nowhere near any road. Tree leaves snag these falling particles through what researchers call the "comb-out effect," and rain washes them down into the soil layer. Forests far from any city or farm are being contaminated this way.

4. Irrigation Water

Crops get watered with water that already contains microplastics, from contaminated rivers, recycled wastewater, or runoff. Every watering cycle deposits a new layer of particles into the ground.

Microplastics In the Soil | Source: plasticpollutioncoalition

Okay, It's in the Soil. So what?

Here's where it gets really uncomfortable.

The annual plastic waste input into land ecosystems is estimated to be 4 to 23 times greater than what enters the oceans. The land has it significantly worse, and it's barely talked about.

Once microplastics are in the soil, they start causing damage in ways that ripple all the way up to us.

They're Wrecking Earthworms

Earthworms are basically the unsung heroes of agriculture. They digest dead organic matter, aerate the soil, and create nutrients for crops. Without them, the soil would be significantly less fertile.

Microplastics are destroying them. Studies show exposure leads to weight loss, reduced reproduction, damaged gut lining, and potentially DNA damage. And here's the cruel twist: as worms burrow through contaminated soil, they actually spread the microplastics deeper underground, distributing the pollution further into the soil profile.

They're Scrambling the Microbial Community

Healthy soil is alive with billions of bacteria and fungi that cycle nutrients, regulate greenhouse gases, and support plant growth. Think of them as the soil's immune system. Microplastics physically alter soil structure, changing how much water and air move through it, and they selectively attract certain microbes over others, throwing the whole community off balance.

They're Disrupting Nitrogen, the Nutrient Crops Need Most

Nitrogen is what plants need to grow. Microplastics from common plastics like polyethylene and PVC interfere with the nitrogen cycle in agricultural soil, reducing the availability of this critical nutrient and lowering crop productivity. In a world that needs to feed 8+ billion people, that's not a small problem.

And Then It Gets Into Us

If the damage to soil and worms and microbes felt abstract, this part won't.

In a real-world study done in traditional home gardens in Mexico, researchers tracked microplastics moving through a complete food chain. They found particles in the soil, then in earthworm castings, then in chicken droppings, and then, in the chicken gizzards that people eat for dinner. Microplastic concentrations jumped from 0.87 particles per gram in soil all the way to 129.8 particles per gram in chicken feces. That's the food chain doing what it does: concentrating everything, including plastic.

Once microplastics enter the food chain, they bioaccumulate. Each step up the chain: soil → worm → chicken → human, concentrates the particles further. And microplastics don't travel alone. They carry toxic chemical additives, pesticides, heavy metals, and even pathogenic microorganisms along for the ride. Exposure has been linked to hormone disruption, inflammation, and increased cancer risk.

So no, this isn't just a problem for earthworms.

Why Aren't More People Talking About This?

Honestly? Because soil is invisible. You don't see it on a beach cleanup. It doesn't make for a dramatic documentary shot the way a turtle with a straw in its nose does. Microplastics in soil are everywhere and nowhere at once, quietly accumulating in farmland, in forests, in city parks, and it takes a microscope just to see the problem.

Research on soil microplastics only really started picking up after 2017. We're still in the early stages of understanding just how bad it is. And that's exactly why this conversation needs to start now.

The wrong time to start talking about a crisis is after it's already irreversible.

What Can You Actually Do?

You don't need to fix everything. But you can be part of making it less bad.

• Wash synthetic clothes in a microfiber-catching laundry bag, it traps fibers before they reach the sewer.

• Drive less, walk or bike more, every car trip sheds tire rubber that ends up in soil and air.

• Choose organic produce when possible, organic farming uses fewer plastic mulch films.

• Support policies that regulate plastic in fertilizers and sewage sludge applied to farmland.

• Talk about this. Seriously. Awareness is how every environmental movement starts.

The Bottom Line

We grew up being told dirt was gross. Ironic, then, that we're the ones making it toxic.

The soil that grows our food, supports our ecosystems, and cycles our nutrients is being steadily contaminated by the plastic we make, use, and discard without a second thought. The earthworms are losing weight. The microbes are off balance. The nitrogen is disrupted. And the particles are working their way up the food chain and toward us.

This is not a problem we can clean up with a beach pickup event. It's not a problem that goes away when we stop looking at it. It's a quiet, slow-moving crisis that demands exactly the thing we're worst at: paying attention before disaster forces us to.

The ocean got its documentary. Now it's the soil's turn. 🌱

References

Yu, Hong, et al. “Microplastics as an Emerging Environmental Pollutant in Agricultural Soils: Effects on Ecosystems and Human Health.” Frontiers in Environmental Science, vol. 10, 2022, article 855292, https://doi.org/10.3389/fenvs.2022.855292.

Chaudhary, Hari Dev, et al. “Microplastics and Plant Health: A Comprehensive Review of Sources, Distribution, Toxicity, and Remediation.” npj Emerging Contaminants, vol. 1, no. 1, 2025, article 8, https://doi.org/10.1038/s44454-025-00007-z.

Wang, Kai, et al. “Microplastics and Soil Microbiomes.” BMC Biology, vol. 23, 2025, article 178, https://doi.org/10.1186/s12915-025-02387-5.

Sarfraz, Umair, et al. “Microplastic Effects on Soil Nitrogen Storage, Nitrogen Emissions, and Ammonia Volatilization in Relation to Soil Health and Crop Productivity: Mechanism and Future Consideration.” Frontiers in Plant Science, vol. 16, 2025, article 1621542, https://doi.org/10.3389/fpls.2025.1621542.