Overview
EN ISO 22404:2021 (identical to ISO 22404:2019) specifies a laboratory test method for determining the aerobic biodegradation of non‑floating plastics exposed to marine sediment by analyzing the carbon dioxide (CO2) evolved. The method simulates the sandy tidal (eulittoral) zone by exposing test specimens to marine sediment kept wet with salt water and monitoring CO2 evolution as a quantitative measure of biodegradation. The standard can also be applied to other non‑floating materials.
Key topics and technical requirements
- Test principle: Biodegradation is quantified from the amount of CO2 produced when the test material is biodegraded by the marine inoculum (sediment + seawater).
- Test environment: Uses sediment sampled from a sandy tidal zone (eulittoral) and controlled laboratory salt‑water conditions to simulate the natural habitat.
- Sample preparation: Refers to established sampling and specimen preparation methods (see ISO 10210 for sample prep guidance).
- Pre‑conditioning and inoculum handling: Includes pre‑conditioning of inoculum and controlled incubation before starting the measurement phase.
- CO2 measurement and calculations: Specifies procedures for measuring evolved CO2 and calculating biodegradation as a percentage of theoretical CO2 (ThCO2) based on total organic carbon (TOC) or molecular composition.
- Test validity and reporting: Defines validity criteria, data interpretation and the required content for the test report. Any deviations from the prescribed conditions must be justified and recorded.
- Scope limits: The laboratory simulation may not represent optimum field conditions for maximum biodegradation; results are specific to the tested conditions.
Applications and users
- Who uses it:
- Test laboratories and conformity assessment bodies performing biodegradation testing
- Plastics and polymer manufacturers assessing environmental behavior of materials intended for marine use
- Product designers (e.g., fishing gear, aquaculture components) evaluating biodegradability risk
- Environmental scientists studying material fate in coastal zones
- Regulators and certification schemes requiring standardized biodegradation data
- Practical applications:
- Quantitative evaluation of biodegradation rates and levels for non‑floating plastics in marine sediment
- Comparative testing of material formulations and additives
- Supporting environmental risk assessments and eco‑design decisions for marine applications
- Generating reproducible laboratory evidence for claims about marine biodegradability
Related standards
- ISO 10210 - Plastics: Methods for preparation of samples for biodegradation testing of plastic materials (referenced for sample preparation).
Keywords: EN ISO 22404:2021, plastics biodegradation, marine sediment test, evolved CO2, aerobic biodegradation, non‑floating materials, eulittoral zone, laboratory biodegradation method.