Biodegradable plastics can be more disruptive to soil health and carbon storage than the conventional plastics they are meant to replace.
March 31, 2026
Original Paper
Divergent aging patterns of polylactic acid (PLA) and polyvinyl chloride (PVC) microplastics and their differential impacts on soil carbon stability along a bulk density gradient
SSRN · 6497855
The Takeaway
The 'biodegradable' label suggests these plastics simply disappear, but they actually recruit specific microbes that speed up the loss of organic carbon from the soil. This study reveals that the eco-friendly alternative creates a complex new set of environmental risks that standard PVC microplastics do not, challenging the assumption that faster breakdown is always better.
From the abstract
Microplastic (MP) pollution is a growing concern. After entering soil, MPs undergo aging that alters their properties and ecological impacts, yet how different polymers age in natural settings and affect soil carbon cycling remains unclear. Here, we conducted a nine‑month in situ experiment comparing the aging of biodegradable polylactic acid (PLA) and conventional polyvinyl chloride (PVC) microplastics, and their effects on soil microbial communities, enzyme activities, and organic carbon fract