Overview
EN ISO 23977-2:2021 / ISO 23977-2:2020 defines a laboratory test method for assessing the aerobic biodegradation of plastic materials exposed to seawater. The method quantifies biodegradation by measuring oxygen demand in a closed respirometer when seawater sampled from coastal areas is used as the inoculum. The test gives an indication of the potential biodegradability of plastics in marine conditions (pelagic and suspended-sediment scenarios), recognizing laboratory conditions may not represent optimal or all field situations.
Key topics and technical requirements
- Principle: Biodegradation is followed by tracking oxygen consumption in a closed respirometric system as microbes mineralize the test material.
- Test configurations:
- Pelagic seawater test - simulates offshore, low-current conditions using seawater only.
- Suspended sediment seawater test - simulates coastal, higher-current or tidal conditions with seawater plus a small amount of sediment.
- Test components covered: sampling and handling of seawater, test material preparation and pre-conditioning, use of reference materials and controls, reagents and apparatus, respirometer setup, start/end criteria, calculations, visual inspection, reporting and validity criteria.
- Data and reporting: Calculation of biodegradation degree and rate from oxygen demand, expression and interpretation of results, and conditions for validating results.
- Scope note: While focused on plastics, the method can also be applied to other materials.
Applications and users
This standard is practical for:
- Environmental testing laboratories performing marine biodegradability assessments.
- Plastics manufacturers and product developers evaluating material formulations for reduced marine persistence.
- Regulatory bodies and certification schemes needing standardized, comparable biodegradability data for marine environmental claims.
- Research institutions and ecotoxicology groups studying microbial degradation processes in marine environments.
- Policy makers and stakeholders interested in evaluating the environmental fate of marine litter and biodegradable plastics.
Use cases include screening candidate materials, generating data for environmental impact assessments, and supporting product declarations about marine biodegradability.
Related standards
EN ISO 23977-2:2021 is part of a broader suite of biodegradation methods. Relevant related standards include:
Keywords: EN ISO 23977-2:2021, ISO 23977-2:2020, plastics biodegradation, seawater respirometer, aerobic biodegradation, pelagic seawater test, suspended sediment test, marine biodegradability.