Microplastics are accumulating in agricultural soils at a rate significantly higher than in oceans, warns a new review from Murdoch University, Australia. The study estimates farms now hold up to 23 times more microplastics than seas. 

According to the findings, microplastics and nanoplastics have now been detected in several key crops, including lettuce, wheat, and carrots. This happens when particles enter soil through means such as plastic mulching, fertilizers, and even through being dropped by clouds.

“These microplastics are turning food-producing land into a plastic sink,” says PhD candidate Joseph Boctor, who led the study.

The research also notes that plastics in soil may carry up to 10,000 chemical additives, most of which are not currently regulated for agricultural use.

This becomes more dangerous when viewed in the context of findings of these plastics in the human lungs, brain, heart, blood, and even placenta.

“And BPA-free does not equal risk-free,” says Boctor. BPA-free means that a product does not contain bisphenol A, which is known to be an endocrine disruptor and interferes with the human body’s hormonal system.

“Replacement chemicals like bisphenol F and bisphenol S show comparable or greater endocrine-disrupting activity.”

Lack of transparency

The review also identifies other additives found in soil, such as phthalates, which research has linked to reproductive issues, and polybrominated diphenyl ethers. These substances have been associated with neurodegenerative diseases, increased risk of stroke and heart attack, and early death.

“These are not distant possibilities — they are unfolding within biological systems — silently and systematically,” says Boctor.

The study notes that the challenge is that regulatory action is slower than science, while the industry works fast.

Moreover, Boctor says assessing toxicity is often overlooked because the plastic industry lacks transparency and produces many additives.

“This makes the plastic crisis unchecked and human health exposed. This review tries to bring this creeping danger under the radar and shine a flashlight on regulators.”

Boctor and colleagues at the university’s Bioplastics Innovation Hub are developing a type of plastic that is safe and degradable in soil, land, and water.

One such project is the Smart Sprays initiative, which tests a bioplastic-based soil spray designed to reduce evaporation and improve rainwater harvesting. The product is designed to integrate with existing farming equipment.

The goal is to introduce a “green plastic” to the market to minimize and eventually negate the need for non-sustainable plastic production.

“This review highlights the urgent need for coordinated scientific and regulatory efforts. Regulators, scientists, and industry must collaborate to close the loopholes before plastic pollution further entrenches itself in the global food chain,” Boctor concludes.

The review is published in the journal Springer Nature.