ISO 17556-2019 PDF

Full title and description

Plastics — Determination of the ultimate aerobic biodegradability of plastic materials in soil by measuring the oxygen demand in a respirometer or the amount of carbon dioxide evolved. ISO 17556:2019 specifies laboratory procedures to assess the ultimate aerobic biodegradation of plastic materials when mixed with soil, using either biochemical oxygen demand (BOD) measurement in a closed respirometer or measurement of CO2 evolved.

Abstract

This International Standard defines a test method to determine the ultimate aerobic biodegradability of plastics in soil. The method measures oxygen consumption (BOD) in a closed respirometer or the amount of CO2 evolved from soil/test-material mixtures under controlled temperature and moisture conditions. It is intended to simulate biodegradation processes occurring in soil (using non‑adapted soil) or to assess potential biodegradability (using pre‑exposed soil). The procedure covers natural and synthetic polymers, polymer blends and formulations (including additives) and water‑soluble polymers, and includes provisions for controls, inhibition checks and calculation of percentage biodegradation against theoretical oxygen/CO2 demand.

General information

• Status: Published (current; confirmed at last ISO review).
• Publication date: May 2019 (Edition 3, 2019).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 83.080.01 — Plastics in general.
• Edition / version: Edition 3 (2019).
• Number of pages: 26 (ISO edition).

Scope

ISO 17556:2019 applies to the laboratory determination of the ultimate aerobic biodegradability of plastic materials in soil by (a) measuring oxygen demand in a closed respirometer or (b) measuring CO2 evolution. The method is designed to promote an optimum degree of biodegradation by controlling soil moisture and incubation conditions. It is applicable to natural and synthetic polymers, copolymers or mixtures, plastic formulations containing additives (plasticizers, colorants, etc.) and water‑soluble polymers. The standard provides procedures for using non‑adapted or pre‑exposed soils, for detecting inhibitory effects, and for calculating biodegradation expressed as percentage of theoretical oxygen demand or theoretical CO2.

Key topics and requirements

• Principle: test material is mixed with soil and biodegradation is quantified by oxygen uptake (BOD) or CO2 evolution compared to theoretical values (ThOD/ThCO2).
• Test variants: closed respirometric BOD measurement or CO2 evolution measurement (continuous or periodic sampling).
• Test environment: incubation in dark or diffused light at 20–28 °C (preferably 25 °C) with controlled humidity and enclosed atmosphere free of toxic vapours.
• Inoculum/soil: use of non‑adapted soil to simulate natural conditions or pre‑exposed soil to investigate potential biodegradability; soil properties (water‑holding capacity, organic carbon content) must be characterised and controlled.
• Controls and references: blank (soil only), reference material (e.g., cellulose) and inhibition controls to detect toxic effects of the test material.
• Test concentration and specimen preparation: guidance on particle size, sample loading (g test material per kg soil) and mixing to ensure the test material is the primary carbon source.
• Duration and interpretation: normal test period is up to 6 months; may be shortened or extended until a plateau (no further significant biodegradation) is reached, but total test duration shall not exceed 2 years.
• Calculations and reporting: formulas for percentage biodegradation from BOD or CO2 data versus theoretical oxygen/CO2 demand; reporting of incubation curve, lag/biodegradation/plateau phases, soil characteristics and any deviations.
• Limitations: not applicable where the test material inhibits microbial activity under test conditions (inhibition must be checked and alternative approaches used if present).

Typical use and users

ISO 17556:2019 is used by testing laboratories, materials manufacturers, product developers, environmental laboratories, certification bodies and regulators to evaluate and compare the biodegradability of plastics in soil conditions. It is commonly applied in R&D for biodegradable formulations, conformity or environmental‑claim substantiation, and in product stewardship or regulatory assessment where soil biodegradation data are required.

Related standards

Standards commonly referenced alongside ISO 17556 include other biodegradability test methods and guidance such as ISO 14851 and ISO 14852 (aerobic biodegradability in aqueous media by oxygen demand or CO2 evolution), ISO 14855 (biodegradability under controlled composting conditions), ISO 9439 (CO2 evolution test for aqueous media), ISO 11266 (sediment/water tests) and relevant OECD and ASTM test methods for biodegradability. National and regional adoptions (EN ISO versions) and sector‑specific compostability or biodegradability specifications are also commonly consulted.

Keywords

ISO 17556, plastics, biodegradability, soil, respirometer, CO2 evolution, biochemical oxygen demand, ThOD, test method, environmental testing, soil biodegradation, polymer testing.

FAQ

Q: What is this standard?

A: ISO 17556:2019 is an International Standard that specifies laboratory methods to determine the ultimate aerobic biodegradability of plastic materials in soil by measuring oxygen demand (BOD) in a closed respirometer or the amount of CO2 evolved.

Q: What does it cover?

A: It covers sample preparation, test conditions (temperature, humidity), selection and preparation of soil inoculum, required controls and reference materials, measurement procedures (BOD or CO2), calculation of percentage biodegradation against theoretical oxygen/CO2 demand, test duration guidance and reporting requirements. It applies to natural/synthetic polymers, polymer blends, formulated plastics (with additives) and water‑soluble polymers.

Q: Who typically uses it?

A: Accredited and commercial testing laboratories, manufacturers and formulators of plastics, product developers, environmental and regulatory bodies, and certification schemes that need soil biodegradability data use this standard.

Q: Is it current or superseded?

A: The 2019 edition (Edition 3) is the current published edition. It replaced the earlier 2012 edition and is subject to periodic ISO review.

Q: Is it part of a series?

A: Yes. ISO 17556 is part of a family of ISO biodegradability standards addressing different environments and measurement methods (for example ISO 14851/14852 for aqueous media and ISO 14855 for composting conditions) and is often used alongside OECD and ASTM biodegradability methods as appropriate.

Q: What are the key keywords?

A: Plastics, biodegradability, soil, respirometer, CO2 evolution, biochemical oxygen demand, ThOD, test method, ISO 17556.