This test is used to determine the degree of aerobic biodegradation of polymeric compounds utilized in plastic materials by determining the level of respiration of such radiolabeled carbon compounds to radiolabeled carbon dioxide. The test is designed to utilize the naturally occurring microbes in seawater as the inoculum for the enrichment and subsequent mineralization (biodegradation) of the test polymer using it as a carbon and energy source resulting in a carbon dioxide as an end product. The test method requires that the polymers to be assayed are synthesized using the radioisotope, carbon-14, and that the compound or plastic material be uniformly labeled with carbon-14. As controls, known biodegradable compounds, such as glucose or starch, also uniformly labeled with carbon-14, are run in order to determine the biological activity of the natural population. The concentration of added polymers shall be kept low so as not to cause limitation by oxygen, and the seawater inoculum is amended with nitrogen and phosphorus compounds to ensure that growth in not limited by these nutrients. The safety problems and regulations associated with working with radioactive materials are not addressed in the method. It is the responsibility of the individual users to establish and ensure adherence the proper safety, health, monitoring and all regulatory practices associated with the use of radioactive compounds. There is no similar or equivalent ISO standard.