1.1 This standard test method determines the biodegradation level of plastic materials exposed to laboratory conditions that simulate the environment found in the tidal zone. 1.2 The tidal zone, i.e. the part of the coast affected by the tides and movement of the waves, is the borderline between sea and land, frequently a sandy area that is kept constantly damp by the lapping of the waves. Stony and rocky shorelines also exist. 1.3 Plastic marine debris is frequently washed up in this habitat where it must be removed in order to restore the original landscape. 1.4 It is of interest to know the biodegradation behavior of plastics when exposed to conditions simulating this habitat, because this information can help in predicting the time needed for the biodegradation of the litter. 1.5 Biodegradation is determined by measuring the carbon dioxide evolved by the plastic material when exposed to a sediment kept wet with salt-water in a reactor, to simulate the tidal zone. 1.6 Marine fresh-water habitats are not considered by this Standard. 1.7 Reports shall clearly state the percentage of net gaseous carbon generation for both the test and reference samples at the completion of the test. Furthermore, in the laboratory reports, the results shall not be extrapolated beyond the actual duration of the test.
Plastic articles which are used in the sea, such as fishing gear, can get lost or left willingly in the marine environment contributing to the marine pollution. Such fishing products could therefore be made with biodegradable plastics, once biodegradation in the sea is characterized. Furthermore, it is of interest to know the marine biodegradation of bioplastics, in case of uncontrolled release. Specific laboratory test methods to determine biodegradation of plastics in different habitats are needed. As a matter of fact, the marine environment includes several different habitats where plastic products that are directly littered or arrive with fresh waters in the sea can end up. This standard will be used by industry, laboratories, and those who are interested in characterising the biodegradation behaviour of plastic products when exposed to the marine environment
Keywordsaerobic; biodegradation; marine; sandy sediment; eulittoral.
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Francesco Degli Innocenti
Ballot Item Approved
Ballot Item Approved as D7991-2015 and Pending Publication