Standard Test Method for Determining Aerobic Biodegradation of Plastics Buried in Sandy Marine Sediment under Controlled Laboratory Conditions

Importancia y uso:

5.1 Plastic is sometimes carried by rivers or accidentally discharged by ships into the sea; this plastic can then reach different parts of the marine environment. Tides and waves also frequently deliver plastic marine debris into the sandy tidal zones.

5.2 This test method simulates the environmental conditions found in the tidal zone. Plastic debris that reaches the sandy tidal zone can settle there and become partially or totally buried by sand and kept wet by waves or tides. It is of interest to assess the biodegradation behavior of plastic materials under these conditions to predict the removal time of this waste in the environment.

5.3 This test method is applied to determine the extent of biodegradation of a plastic exposed in the laboratory to a sandy sediment kept wet with seawater. Both sediment and seawater are collected from a sandy beach in the tidal zone. If the natural microbial population present in the sediment is able to biodegrade the plastic, there will be an evolution of CO₂ as a consequence of the aerobic microbial respiration. The level of biodegradation at any given time is the ratio between the cumulative amount of the evolved net carbon dioxide and the theoretical amount produced in the case of total conversion of the organic carbon present in the plastic into carbon dioxide.

5.4 This test method does not measure the amount of organic carbon that is converted into biomass, but only the biodegradation that leads to mineralization (that is, the formation of CO₂).

Subcomité:

D20.96

Volúmen:

08.03

Número ICS:

83.080.01 (Plastics in general)

Palabras clave:

aerobic; biodegradation; marine; sandy sediment; tidal;