A recent study published by the PAPILLONS consortium has examined how biodegradable microplastics—specifically PBAT (polybutylene adipate terephthalate)—affect soil microbial communities and activities under controlled conditions. This material, commonly used in agricultural mulching films, is marketed as biodegradable, but its environmental impacts remain under scrutiny.
Researchers conducted a controlled experiment in a climate-controlled system called a “mesocosm”. They added varying amounts of PBAT microplastics (ranging from 0% to 0.8% of soil weight) to soil columns planted with lettuce and inhabited by common soil animals like earthworms and springtails. The experiment lasted 11 weeks.
Researchers observed significant changes in the soil’s microbial ecology:
– Increased microbial diversity: Both bacterial and fungal communities became more diverse as microplastic concentrations increased.
– Bacterial and fungal communities differed between the control and 0.8 % PBAT treatment.
– Shifts in community structure: Certain bacterial groups linked to soil health declined, while others associated with nitrogen cycling increased.
– Elevated soil respiration: CO₂ emissions rose with higher microplastic levels, suggesting altered microbial activity.
– Soil pH changes: A slight increase in pH was observed, potentially influencing microbial dynamics.
In sum, the presence of biodegradable microplastics, even at low concentrations, can significantly influence soil microbial composition and function. These findings raise important questions about the use of such materials in agriculture and their long-term effects on soil ecosystems.
The study underscores the need for further research, particularly under real-world field conditions, to better assess the sustainability of biodegradable plastics in farming.
Read the full article here: https://www.sciencedirect.com/science/article/pii/S0048969725009246?via%3Dihu