# Impacts of pristine, aged and leachate of conventional and biodegradable plastics on plant growth and soil organic carbon

## TL;DR

This study shows that both regular and biodegradable plastics, whether new or aged, harm plant growth and soil health, suggesting potential long-term environmental impacts.

## Contribution

The study is the first to compare the effects of aged and leachate from biodegradable and conventional plastics on plant growth and soil properties.

## Key findings

- Root and shoot biomass and chlorophyll content decreased in soil exposed to plastics and their leachates.
- Soil pH and organic matter content were significantly reduced, while CO2 respiration increased.
- Meso and micro plastic films had similar impacts on plants and soil properties.

## Abstract

Plastic is an essential component of agriculture globally, becoming a concerning form of pollution. Biodegradable alternatives are gaining attention as a potential replacement for commonly used, non-degradable plastics, but there is little known about the impacts of biodegradable plastics as they age and potential leachates are released. In this study, different types (conventional: polyethylene and polypropylene and biodegradable: polyhydroxybutyrate and polylactic acid) of micro- and meso-films were added to soil at 0.1% (w/w) prior to being planted with Lolium perenne (perennial ryegrass) to evaluate the plant and soil biophysical responses in a pot experiment. Root and shoot biomass and chlorophyll content were reduced when soil was exposed to plastics, whether conventional or biodegradable, pristine, aged or when just their leachate was present. The pH and organic matter content of soil exposed to these plastics and their leachates was significantly reduced compared to control samples; furthermore, there was an increase in CO2 respiration rate from soil. In general, meso (> 5 mm) and micro (< 5 mm) plastic films did not differ in the impact on plants or soil. This study provides evidence that conventional and biodegradable plastics have both physical and chemical impacts on essential soil characteristics and the growth of L. perenne, potentially leading to wider effects on soil carbon cycling.

The online version contains supplementary material available at 10.1007/s11356-024-31838-9.