Effect of bio-based microplastics on earthworms Eisenia andrei

Area of Science:

• Environmental Science
• Ecotoxicology
• Biotechnology

Background:

• The global market for bio-based plastics is expanding, necessitating environmental impact assessments.
• Earthworms (Eisenia andrei) are crucial terrestrial ecosystem bioindicators.
• Understanding bio-based plastic effects on soil organisms is vital for ecological risk assessment.

Purpose of the Study:

• To evaluate the long-term impact of three novel bio-based plastics on earthworm Eisenia andrei.
• To assess effects on earthworm mortality, body mass, reproduction, and oxidative stress responses.
• To determine the efficacy of catalase (CAT) and superoxide dismutase (SOD) as biomarkers.

Main Methods:

• Long-term exposure experiments with earthworms Eisenia andrei.
• Testing of two polylactic acid-based (PLA-based) plastics and one poly(hydroxybutyrate-co-valerate)-based (PHBV-based) plastic.
• Measurement of earthworm mortality, body mass, reproduction, and antioxidant enzyme activities (CAT, SOD).

Main Results:

• No significant impact on earthworm mortality or body mass observed, even at 12.5% w/w concentration.
• Earthworm reproduction was significantly reduced at 12.5% w/w for all tested bio-based plastics.
• PLA-based plastics showed a stronger negative effect on reproduction than PHBV-based plastic.
• Catalase (CAT) activity increased significantly (16-84%) in earthworms exposed to bio-based plastics, indicating oxidative stress.
• CAT activity proved a sensitive indicator of bio-based plastic-induced cellular responses.

Conclusions:

• Earthworm reproduction ability is a sensitive endpoint for evaluating bio-based plastic ecotoxicity.
• Catalase activity serves as a reliable biomarker for oxidative stress induced by bio-based plastics in earthworms.
• Reproduction and CAT activity are recommended for assessing the environmental impact of bio-based plastics on earthworms.