ASTM D6691-01

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. Biodegradable plastics may 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.

The degree and rate of aerobic biodegradability of a plastic under the conditions of this test method may be used to estimate the persistence of that plastic in biologically active marine environments, for example, seashore and open-ocean. However, 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.

1.1 This test method is used to determine the degree and rate of aerobic biodegradation of plastic materials (including formulation additives) exposed to pre-grown population of at least ten aerobic marine microorganisms of known genera. The test method is conducted under controlled laboratory conditions.

1.2 This test method is designed to index polymer materials that are possibly biodegradable, relative to a positive reference material, in an aerobic environment.

1.3 This test method is applicable to all polymer materials containing at least 20 % carbon that are not inhibitory to the microorganisms present in a marine environment.

1.4 The values stated in SI units are to be regarded as the standard.

1.5 There is no similar or equivalent ISO standard.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.