Advancing the Standards of Functional Polymers
ASTM D6691
Standard Test Method for Determining Aerobic Biodegradation* of Plastic Materials in the Marine Environment by a Defined Microbial Consortium or Natural Sea Water Inoculum
Significance and Use (There is no known ISO equivalent to this standard)
The use of plastics aboard ships is on the rise and the use of the sea as a trash dumping site is no longer a possibility; consequently, the disposal of plastic materials while at sea remains a major issue. It is possible that biodegradable plastics will help to allay public concern by allowing for the safe disposal of plastic materials at sea. This test method has been developed to assess the rate and degree of aerobic biodegradation of plastics exposed to marine microorganisms. Aerobic biodegradation is determined by measuring the amount of biogas (carbon dioxide) produced during such an exposure.
It is acceptable to use the degree and rate of aerobic biodegradability of a plastic under the conditions of this test method to estimate the persistence of that plastic in biologically active marine environments, for example, seashore and open-ocean.
Limitations
It shall be recognized that predicting long-term environmental fate and effects from the results of short-term exposure to a simulated marine environment is difficult. Thus, caution shall be exercised when extrapolating the results obtained from this or any other controlled-environment test to disposal in the natural environment.
* 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.