ASTM D5988-96
(Test Method)Standard Test Method for Determining Aerobic Biodegradation in Soil of Plastic Materials or Residual Plastic Materials After Composting
Standard Test Method for Determining Aerobic Biodegradation in Soil of Plastic Materials or Residual Plastic Materials After Composting
SCOPE
1.1 This test method covers determination of the degree and rate of aerobic biodegradation of synthetic plastic materials (including formulation additives that may be biodegradable) in contact with soil, or a mixture of soil and mature compost, under laboratory conditions.
1.2 This test method is designed to rate the biodegradability of plastic materials relative to a standard 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 and compost.
1.4 The values stated in SI units are to be regarded as the standard.
1.5 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.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 5988 – 96
Standard Test Method for
Determining Aerobic Biodegradation in Soil of Plastic
Materials or Residual Plastic Materials After Composting
This standard is issued under the fixed designation D 5988; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope Organic Solvents and Their Admixtures
D 4129 Test Method for Total and Organic Carbon in Water
1.1 This test method covers determination of the degree and
by High-Temperature Oxidation and Coulometric Detec-
rate of aerobic biodegradation of synthetic plastic materials
tion
(including formulation additives that may be biodegradable) in
D 4972 Test Method for pH of Soils
contact with soil, or a mixture of soil and mature compost,
D 5338 Test Method for Determining Aerobic Biodegrada-
under laboratory conditions.
tion of Plastic Materials Under Controlled Composting
1.2 This test method is designed to rate the biodegradability
Conditions
of plastic materials relative to a standard in an aerobic
D 5511 Test Method for Determining Anaerobic Biodegra-
environment.
dation of Plastic Materials Under High-Solids Anaerobic-
1.3 This test method is designed to be applicable to all
Digestion Conditions
plastic materials that are not inhibitory to the bacteria and fungi
2.2 APHA-AWWA-WPCF Standards:
present in soil and compost.
2540 D Total Suspended Solids Dried at 103°–105°C
1.4 The values stated in SI units are to be regarded as the
2540 G Total, Fixed, and Volatile Solids in Solids and
standard.
Semi-Solid Samples
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
3.1 Definitions—Definitions of terms applicable to this test
priate safety and health practices and determine the applica-
method appear in Terminology D 883.
bility of regulatory limitations prior to use. A specific hazard
statement is given in Section 8.
4. Summary of Test Method
NOTE 1—There is no ISO standard that is equivalent to this test method.
4.1 The test method described consists of the selection of
plastic material or compost containing residual plastic material
2. Referenced Documents
after composting for the determination of aerobic biodegrad-
2.1 ASTM Standards:
ability, obtaining soil as a matrix and source of inoculum,
D 425 Test Method for Centrifuge Moisture Equivalent of
exposing the plastic materials or the compost containing
Soils
residual plastic material to the soil, measuring the carbon
D 618 Practice for Conditioning Plastics and Electrical
dioxide evolved by the microorganisms as a function of time,
Insulating Materials for Testing
and assessing the degree of biodegradability.
D 883 Terminology Relating to Plastics
4.2 The CO production measured for a material, expressed
D 1193 Specification for Reagent Water
as a fraction of the measured or calculated carbon content, is
D 1293 Test Methods for pH of Water
reported with respect to time, from which the degree of
D 1898 Practice for Sampling of Plastics
biodegradability is assessed.
D 2980 Test Method for Volume Weights, Water-Holding
Capacity, and Air Capacity of Water-Saturated Peat Mate- 5. Significance and Use
rials
5.1 The degree and rate of aerobic biodegradability of a
D 2989 Test Method for Acidity-Alkalinity of Halogenated
plastic material in the environment determines the extent to
1 5
This test method is under the jurisdiction of ASTM Committee D-20 on Plastics Annual Book of ASTM Standards, Vol 15.05.
and is the direct responsibility of Subcommittee D20.96 on Environmentally Annual Book of ASTM Standards, Vol 11.02.
Degradable Plastics. Annual Book of ASTM Standards, Vol 04.09.
Current edition approved July 10, 1996. Published September 1996. Annual Book of ASTM Standards, Vol 08.03.
2 9
Annual Book of ASTM Standards, Vol 04.08. Standard Methods for the Examination of Water and Wastewater, 17th Edition,
Annual Book of ASTM Standards, Vol 08.01. 1989, American Public Health Association (APHA), 1015 Fifteenth Street NW,
Annual Book of ASTM Standards, Vol 11.01. Washington, DC 20005.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 5988
which and time period over which plastic may be mineralized. 6.1.4 Darkened Chamber or Cabinet, in which the tempera-
Disposal is becoming a major issue with the increasing use of ture is maintained at 21 6 2°C.
plastics, and the results of this test method may permit an 6.2 Analytical Equipment:
estimation of the degree of biodegradability and the time 6.2.1 Analytical Equipment, to measure the total carbon
period over which plastics will remain in an aerobic soil content of the test specimen.
environment. This test method determines the degree of 6.2.2 Analytical Balance, to weigh the test specimen.
aerobic biodegradation by measuring evolved carbon dioxide 6.2.3 Burette, 100 mL.
as a function of time that the plastic is exposed to soil. 6.2.4 Bench-Top Centrifuge, for moisture-holding capacity
5.2 Soil is an extremely species-rich source of inoculum for (MHC) determination.
evaluation of the biodegradability of plastics in the environ- 6.2.5 Oven, set to 104 6 1°C for moisture determinations.
ment. When maintained appropriately with regard to moisture 6.2.6 Muffle Furnace, set to 550°C for ash determinations.
content and oxygen availability, the biological activity is quite 6.2.7 pH Meter.
considerable, although lower than other biologically active
7. Reagents and Materials
environments, such as activated sewage-sludge or compost.
Soil is also the application target for composted materials, and 7.1 Purity of Reagents—Reagent grade chemicals shall be
therefore the biodegradability of such materials should be used in all tests. Unless otherwise indicated, it is intended that
evaluated in the soil environment after the materials have been all reagents conform to the specifications of the Committee on
composted. A mixture of soil and mature compost containing Analytical Reagents of the American Chemical Society where
composted plastic material (as obtained after performing Test such specifications are available. Other grades may be used,
Method D 5338) is therefore also an appropriate matrix for provided it is first ascertained that the reagent is of sufficiently
evaluation of the biodegradability of plastics.
high purity to permit its use without lessening the accuracy of
the determination.
6. Apparatus
7.2 Ammonium phosphate, ((NH ) HPO ), 4.72 g/L.
4 2 4
7.3 Barium Hydroxide Solution (0.025 N), prepared by
6.1 Soil-Contact Incubation Apparatus (see Fig. 1; biom-
eter flasks are also appropriate): dissolving 4.0 g anhydrous Ba(OH) /L of distilled water. Filter
free of solid material, confirm normality by titration with
6.1.1 Vessels, a set of approximately 2 to 4-L internal
volume that can be sealed air-tight, such as 150-mm desicca- standard acid, and store sealed as a clear solution to prevent
tors. For testing a plastic material in soil: three vessels for soil absorption of CO from the air. It is recommended that 5 to 20
L be prepared at a time when running a series of tests. When
only controls, three for a positive control material, and three
per test material. For testing a compost containing residual using Ba(OH) , however, care must be taken that a film of
BaCO does not form on the surface of the solution in the
plastic material: three for soil only controls, three for a positive
control material in soil, three for the compost-soil control, and beaker, which would inhibit CO diffusion into the absorbing
medium. Alternatively, potassium hydroxide solution (KOH,
three per compost containing test material (optional: three for
the compost containing the positive reference from the previ- 0.5 N) could be used and is prepared by dissolving 28 g of
anhydrous KOH/L of distilled water and proceeding in the
ous composting test). In either case, three vessels may also be
included as technical controls, containing only the absorbing same way as for the KOH.
7.4 Hydrochloric acid, 0.05 N HCl when using 0.025 N
solution and no soil.
6.1.2 Beakers, sets of 150 and 100-mL, equal in number to Ba(OH) , or 0.25 N HCl when using 0.5 N KOH.
the soil incubation vessels.
8. Hazards
6.1.3 Perforated Plates or Other Support, a set to hold the
8.1 This test method includes the use of hazardous chemi-
beakers above the soil inside each vessel.
cals. Avoid contact with chemicals and follow the manufactur-
er’s instructions and material safety data sheets.
9. Soil
9.1 The soil can be a laboratory mixture of equal parts (by
weight) of sand, topsoil, and composted manure or a natural
soil sample. The soil should not be handled in any way that
would inhibit the activity of the soil microorganisms. In the
case of a natural soil, it is advisable to avoid soils that have
been exposed to pollutants that may cause a significant
perturbation of the microbial population. The source of the soil
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
NOTE 1—(1) Barium hydroxide solution or potassium hydroxide solu-
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
tion, (2) soil, (3) water, and (4) perforated plate.
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
FIG. 1 Soil-Contact Incubation Apparatus MD.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 5988
must be reported (see 14.1.1). The test soil may also be a 11.4 Add the test specimen or positive control to the soil
mixture of a natural soil and a mature compost, as obtained at
(approximately 200 mg to 1000 mg carbon for 500 g soil), and
the end of Test Method D 5338. A ratio of 1 g compost to 25 mix the soil thoroughly. In the case of compost with plastic
g soil corresponds to a typical application of approximately
materials coming from Test Method D 5338 or Test Method
120 tons of compost per hectare of agricultural land, assuming
D 5511, the amount of compost should be 20 to 50 g added to
−3
20 cm of soil depth and a bulk density of 1.5 Mg m .
500 g of soil.
9.2 The soil is sieved to less than 2-mm particle size, and
11.5 Record the weight of the vessel and lid (with the
obvious plant material, stones, or other inert materials should
necessary amount of stopcock grease to seal air-tight) with
be removed. The soil is then stored in a sealed container at 4 6
amended soil.
1°C for a maximum of one month.
11.6 Place 100 mL of 0.025 N barium hydroxide solution in
9.3 The soil is analyzed for MHC by Test Method D 425,
a 150-mL beaker (or 20 mL of 0.5 N KOH in a 100-mL beaker)
Test Method D 2980, or another analogous test method for
and 50 mL of distilled water in a 100-mL beaker on the
MHC or field capacity.
perforated plate inside the vessel; seal the vessel and place it in
9.4 The pH of the soil is determined on a 5:1 (distilled
the dark chamber or cabinet at 21 6 2°C.
water:soil) slurry using a glass combination electrode cali-
11.7 Carbon Dioxide Analysis:
brated with standard buffers, following the guidelines given in
11.7.1 The carbon dioxide produced in each vessel reacts
Test Methods D 1293. The pH must fall between 6.0 and 8.0.
(Soil with a pH above 8.0 may retain more of the CO evolved with Ba(OH) and is precipitated as barium carbonate
2 2
(BaCO ). The amount of carbon dioxide produced is deter-
by the microorganisms than a neutral soil, and soil with a pH
below 6.0 may have an atypical microbial population.) Alter- mined by titrating the remaining barium hydroxide with 0.05 N
natively, the soil pH may be determined by Test Method hydrochloric acid to a phenolphthalein end-point or by auto-
D 4972. matic titrator. Because of the static incubation, the barium
9.5 The moisture (total solids—dry solids) and ash (total
carbonate builds up on the surface of the liquid and must be
solids—volatile solids) contents of the soil are determined in broken up periodically by shaking the vessel gently to ensure
accordance with APHA-AWWA-WPCF 2540 D and G, respec-
continued absorption of the evolved carbon dioxide. (This
tively. problem can be avoided by using KOH instead of Ba(OH) ,
which does not form a precipitate.)
10. Test Specimen
11.7.2 The barium hydroxide traps must be removed and
10.1 Test specimens should be of known weight and have
titrated before their capacity is exceeded. Considering that a
sufficient carbon content to yield carbon dioxide that can be
150-mm desiccator vessel provides approximately 2000 cm
measured accurately by the trapping procedure described in
headspace, which under standard conditions contains approxi-
this test method (see 11.1 and 11.4). The carbon content of the
mately 18.7 mmol O , then 100 mL Ba(OH) has the capacity
2 2
test material may be determined by calculation or elemental
to trap approximately 2.5 mmol CO . Therefore, assuming a
analysis, according to Test Method D 4129.
respiratory quotient of 1.0, the O content of the vessel
10.2 Test specimens may be in the form of films, pieces,
headspace will never fall below approximately 18 % if the trap
fragments, powders, or formed articles, or in aqueous solution,
is changed before saturation is reached. The period of time will
and they should be in accordance with Practice D 618. Any test
vary with soils and test materials and increases slowly as the
specimens in the form of powders should be characterized as to
carbon content of the soil is reduced (a recommended fre-
particle size distribution by sieve analysis.
quency of every 3 to 4 days for the first 2 to 3 weeks and every
10.3 Test specimens can be added directly to the soil matrix
1 to 3 weeks thereafter). At the time of removal of the traps, the
or, alternatively, after being submitted to a composting test
vessel should be weighed to monitor moisture loss from the
(Test Method D 5338). In the latter case, a homogenous and
soil and allowed to sit open so that the air is refreshed before
representat
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.