Advancing the Standards of Functional Polymers
ASTM D5988 (ISO 17556)
Standard Test Method for Determining Aerobic Biodegradation* of Plastic Materials in Soil
Significance and Use (This ASTM test method is equivalent to ISO 17556)
The degree and rate of aerobic biodegradability of a plastic material in the environment determines the extent to which and time period over which plastic materials are mineralized by soil microorganisms. Disposal is becoming a major issue with the increasing use of plastics, and the results of this test method permit an estimation of the degree of biodegradability and the time period over which plastics will remain in an aerobic soil environment. This test method determines the degree of aerobic biodegradation by measuring evolved carbon dioxide as a function of time that the plastic is exposed to soil.
5.2 Soil is an extremely species-rich source of inoculum for evaluation of the biodegradability of plastics in the environment. When maintained appropriately with regard to moisture content and oxygen availability, the biological activity is quite considerable, although lower than other biologically active environments, such as activated sewage-sludge or compost.
Limitations
Claims of performance shall be limited to the numerical result obtained in the test and not be used for unqualified “biodegradable” claims. Reports shall clearly state the percentage of net gaseous carbon generation for both the test and reference samples at the completion of the test. Results shall not be extrapolated beyond the actual duration of the test.
* Disclaimer: Biodegradation metrics for plastic materials enhanced with EcoPure® masterbatches are determined strictly according to standardized laboratory test methods (including applicable ASTM and ISO protocols) specific to controlled, biologically active waste environments. Actual real-world biodegradation outcomes[or behavior] vary significantly based on the structural characteristics characteristics of the finished product, material thickness, mass configuration, and localized environmental variables including microbial population density, solid content, temperature, and moisture levels.
In accordance with international advertising and environmental marketing standards, product performance claims must be confined strictly to the exact numerical results achieved within the specific test duration and shall not be used to substantiate unqualified “biodegradable” or “eco-friendly” claims. Testing documentation must explicitly disclose the net percentage of gaseous carbon evolution achieved by both the test sample and the control reference sample at the formal conclusion of the test. Data shall not be extrapolated, projected, or modeled beyond the actual, completed timeline of the laboratory test.
California: (Public Resources Code § 42357): California completely prohibits selling any plastic product or packaging labeled with the terms “biodegradable,” “degradable,” or “decomposable.” It bars any text, imagery, or scientific references—including specific ASTM or ISO test numbers—that imply the item will break down in a landfill or any other environment when directed at consumers. This applies to all sales within or into the state, including internet sales.
Maryland: (Environmental Code § 9-2101): Maryland completely bans express or implied degradation language on plastic products or packaging sold into the state. Citing laboratory test protocols to consumer audiences is restricted and treated as an illegal implied degradation claim.
Minnesota: (Minnesota Statutes § 325E.94): Minnesota bans the manufacture or sale of any plastic product labeled “biodegradable,” “degradable,” or “decomposable,” or relying on implied breakdown mechanisms, unless it meets an authorized, active state-approved standard for rapid environmental assimilation. Citing standard soil or landfill test protocols on consumer packaging does not bypass this ban.
Washington: (Revised Code of Washington § 70A.455): Washington restricts degradability claims on plastic products strictly to items that meet certified compostability standards (such as ASTM D6400 or D6868). All unqualified “biodegradable” claims and implied laboratory-test marketing on non-compostable plastics are prohibited on commercial consumer goods.