Fertilizers that flush microplastics are increasingly spreading across American farmlands, research shows that new concerns about soil contamination and safety in US food supplies.
Peer-reviewed University of Missouri papers found that common types of slow release fertilizers are often encapsulated in plastic and small enough to be considered microplastics. These are designed to break down into smaller plastics when spread across the field.
Small bits of plastic can end up in water and soil at an astonishing level, the paper’s lead author said, and the material is probably being featured in crops. Until now, slow fertilizers have been considered safe, said Maryam Salehi, lead author and researcher at the University of Missouri.
“We need to let the farmers know,” Salehi said. “When they choose a product, they need to know that these have some potential risks.
Microplastics are small bits of plastic that are intentionally added to consumer goods or are broken products of larger plastic. The particles contain 16,000 plastic chemicals that thousands of people pose serious health risks, including BPA, phthalates, and PFA.
This substance has been discovered throughout the human body and is associated with an increased risk of heart attacks and cancer. It is also believed to be a neurotoxic substance that can cause multiple forms of brain dysfunction, such as Parkinson’s disease.
Salehi said it is unknown that other chemicals are found in fertilizer plastics.
Testing has found a wide range of food microplastics, including agricultural products.
Some of the slow release fertilizers are less than 5 mm, so by definition it becomes microplastics. But once they enter the soil, when the tractor runs over them, or when someone walks the ground where they spread out, they “break into small particles,” Salehi said.
That’s a concern, Salehi said, as smaller bits can move around the environment more easily than larger plastics. This study found that most of the microplastics remained in the soil, but some were washed away by rain and irrigation processes to nearby water sources.
This paper did not measure how much of the microplastics became crops, but previous studies found that they could be covered. Other papers have found that bits of plastic can actually reduce soil quality.
“There is even more concern about the impact on food safety,” Salehi said.
However, the problem is fairly easy to solve. According to Salehi, there are many different types of slowly released fertilizers, including those encapsulated with biodegradable materials. However, the plastic version works well so for now the industry seems to be sticking to them, she added.
