Overview
EN ISO 23977-1:2021 (ISO 23977-1:2020) specifies a laboratory test method to determine the aerobic biodegradation of plastic materials exposed to seawater. The method quantifies biodegradation by measuring carbon dioxide (CO2) evolved from test specimens when incubated with seawater sampled from coastal areas. The procedure gives an indication of potential biodegradability under controlled laboratory conditions and can also be applied to other materials beyond plastics. Note: the test conditions may not represent optimal or full-scale environmental degradation.
Key topics and technical requirements
- Principle: Biodegradation is followed respirometrically by analysis of evolved CO2 as plastics are metabolized by marine microorganisms.
- Test environments: Uses pelagic seawater (simulating offshore/low-current conditions) or seawater with suspended sediment (simulating coastal/high-current conditions).
- Test components covered in the standard:
- Selection and preparation of test material and reference materials
- Sampling and handling of coastal seawater as the microbial inoculum
- Required reagents, apparatus, and an example respirometric system (informative annex)
- Test setup and pre-conditioning steps
- CO2 measurement methods and monitoring during the test
- Calculation of CO2 produced and expression of biodegradation as a percentage
- Visual inspection, validity criteria and test report requirements
- Data and interpretation: Procedures for calculating the amount of CO2 evolved, converting to percentage biodegradation, and documenting results.
Applications and who uses it
This standard is intended for:
- Materials scientists and polymer formulators evaluating marine biodegradability of new polymers or additives
- Environmental testing laboratories performing standardized biodegradation assays
- Regulatory agencies and certification bodies assessing environmental claims
- Product designers and manufacturers seeking data for eco-design or sustainability assessments
- Researchers studying plastic persistence and ecological impact in marine environments
Practical uses include screening candidate materials for marine biodegradability, supporting environmental risk assessments, generating comparative data for product development, and informing lifecycle or eco-labeling studies. The standard also cautions that biodegradability is not an excuse to release waste into the environment.
Related standards
EN ISO 23977-1 is part of a family of biodegradation test methods. Related ISO tests address other environments and conditions, for example:
Keywords: ISO 23977-1, EN ISO 23977-1:2021, plastics biodegradation, seawater biodegradation, evolved CO2, respirometric test, marine environment, laboratory test method.
