Macro- and microplastics leachates: Characterization and impact on seed germination

Area of Science:

• Agricultural Science
• Environmental Science
• Soil Science

Background:

• Plastic mulches improve crop yields but pose disposal challenges, leading to soil pollution.
• Macro- and microplastic contamination from agricultural films impacts soil and plant health.
• Leached chemical additives from plastic mulches are potential sources of toxicity.

Purpose of the Study:

• To assess the impact of nondegradable LDPE-based (LDPEb) and biodegradable PBAT-based (PBATb) mulch leachates and particles on seed germination.
• To compare the toxicity of leachates from different mulch types.
• To determine if plastic particles themselves affect germination.

Main Methods:

• Incubation of three plant species (Arabidopsis, cotton, tomato) with LDPEb and PBATb mulch leachates and particles.
• Seven-day incubation period to observe germination rates.
• Analysis of leached compounds and their effects on germination.

Main Results:

• PBAT mulch leachates significantly inhibited Arabidopsis germination; cotton and tomato showed tolerance.
• PBATb mulch released higher concentrations of compounds compared to LDPEb mulch.
• LDPEb mulch leached a greater diversity of chemical compounds.
• Microplastic particles alone did not affect seed germination.

Conclusions:

• Plastic mulch toxicity primarily stems from leached compounds, not the particles themselves.
• Leachates from biodegradable PBAT mulch pose a significant risk to sensitive plant species.
• Many leached compounds lack regulation, necessitating further research and regulatory frameworks for agricultural plastics.