Significance and Use

The degree and rate of aerobic biodegradability of a plastic material in the environment determines the extent to which and time period over which plastic materials are mineralized by soil microorganisms. Disposal is becoming a major issue with the increasing use of plastics, and the results of this test method permit an estimation of the degree of biodegradability and the time period over which plastics will remain in an aerobic soil environment. This test method determines the degree of aerobic biodegradation by measuring evolved carbon dioxide as a function of time that the plastic is exposed to soil.

Soil is an extremely species-rich source of inoculum for evaluation of the biodegradability of plastics in the environment. When maintained appropriately with regard to moisture content and oxygen availability, the biological activity is quite considerable, although lower than other biologically active environments, such as activated sewage-sludge or compost.

1. Scope

1.1 This test method covers determination under laboratory conditions of the degree and rate of aerobic biodegradation of plastic materials, including formulation additives, in contact with soil.

1.2 This test method is designed to measure the biodegradability of plastic materials relative to a reference material in an aerobic environment.

1.3 This test method is designed to be applicable to all plastic materials that are not inhibitory to the bacteria and fungi present in soil.

1.4 Claims of performance shall be limited to the numerical result obtained in the test and not be used for unqualified biodegradable claims. Reports shall clearly state the percentage of net gaseous carbon generation for both the test and reference samples at the completion of the test. Results shall not be extrapolated beyond the actual duration of the test.

1.5 The values stated in SI units are to be regarded as the 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. A specific hazard statement is given in Section 8.

1.7 This ASTM test method is equivalent to ISO 17556.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D425 Test Method for Centrifuge Moisture Equivalent of Soils

D618 Practice for Conditioning Plastics for Testing

D883 Terminology Relating to Plastics

D1193 Specification for Reagent Water

D1293 Test Methods for pH of Water

D2980 Test Method for Volume Mass, Moisture-Holding Capacity, and Porocity of Saturated Peat Materials

D2989 Test Method for Acidity-Alkalinity of Halogenated Organic Solvents and Their Admixtures

D4129 Test Method for Total and Organic Carbon in Water by High Temperature Oxidation and by Coulometric Detection

D4972 Test Method for pH of Soils

D5338 Test Method for Determining Aerobic Biodegradation of Plastic Materials Under Controlled Composting Conditions, Incorporating Thermophilic Temperatures

D5511 Test Method for Determining Anaerobic Biodegradation of Plastic Materials Under High-Solids Anaerobic-Digestion Conditions

APHA-AWWA-WPCF Standards

ISO Standard

Keywords

aerobic; biodegradation; degree (of biodegradation); mineralization; plastics; soil ;

ICS Code

ICS Number Code 13.030.10 (Solid wastes)

DOI: 10.1520/D5988-12

ASTM International is a member of CrossRef.

ASTM D5988