Nanoplastic Produced by Earthworms

Earthworms Ingesting Microplastics
Excrete Smaller Nanoplastics
Serious Impact on Soil Ecosystem

[Asia Economy Reporter Junho Hwang] Amid the increase in disposable product usage due to the spread of the novel coronavirus infection (COVID-19), a study has emerged highlighting the growing severity of the microplastic problem. Earthworms, which burrow through the soil supplying oxygen and nutrients, have been found to break down microplastics into nanoplastics when they ingest them. There is increasing concern that secondary microplastics broken down to the nano scale could affect soil species and extend their impact across the entire ecosystem.

Earthworms That Ingest Microplastics Release Nanoplastics

The National Research Foundation of Korea announced on the 16th that a research team led by Professor Yoonju Ahn from the Department of Environmental Health Science at Konkuk University published findings in the international environmental science journal 'Journal of Hazardous Materials' showing that microplastics in soil can be broken down into nanoplastics through earthworm ingestion activities.

The research team visually demonstrated that microplastics in the soil environment can be reduced to invisible sizes and re-released through earthworm castings by using earthworms, a representative species inhabiting soil. They observed particulate matter obtained from the castings of earthworms cultured for three weeks in soil samples contaminated with microplastics using a scanning electron microscope. Through this, they confirmed the presence of particulate matter smaller than microplastics in the earthworm castings. Additionally, they verified the existence of nanoplastics, clearly distinguishable from soil particles, by analyzing the composition of the particulate matter using X-ray spectroscopy.

This proved that earthworms ingest microplastics buried in the soil and release even smaller nanoplastics.

Need to Understand the Impact of Nanoplastics

A coffee shop located in a government office building in Seoul has a large stack of plastic cups inside the store. Photo by Yoon Dong-ju doso7@

In particular, the research team found that earthworms exposed to microplastics experienced inhibited normal sperm formation, which could lead to reproductive difficulties.

The research team stated, "It is already difficult to accurately assess the environmental impact of microplastics smaller than 5 mm, and nanoplastics smaller than 100 nanometers (nm) are even harder to trace back to their sources," adding, "We believe it is necessary to investigate the distribution of nanoplastics in soil and their effects on soil organisms in the future."

This content was produced with the assistance of AI translation services.