ASTM D6340-98(2007)
(Test Method)Standard Test Methods for Determining Aerobic Biodegradation of Radiolabeled Plastic Materials in an Aqueous or Compost Environment (Withdrawn 2016)
Standard Test Methods for Determining Aerobic Biodegradation of Radiolabeled Plastic Materials in an Aqueous or Compost Environment (Withdrawn 2016)
SIGNIFICANCE AND USE
These test methods can provide direct and unequivocal evidence of aerobic biodegradability. This requires that the radiochemical purity of the plastic is verified using Test Method D 5296.
These methods also provide the opportunity to determine the rate of biological oxidation in a complete composting environment or aqueous environment by frequent periodic sampling of carbon dioxide.
These methods provide biodegradation data at use levels of the plastic in a full cycle composting process or an aqueous system.
SCOPE
1.1 These test methods directly determine the rate and degree of biological oxidation of carbon in plastic materials when placed in a composting environment containing simulated municipal solid waste or an aqueous environment under laboratory conditions.
1.2 Test Method A utilizes a mixed culture derived from the target environment (waste water, sewage sludge, compost eluant, and other environmental sources). Temperature, mixing, and aeration are monitored and controlled.
1.2.1 This method has the sensitivity to determine biodegradation at concentrations commonly found in these environments.
1.3 Test Method B starts with fresh compost and proceeds through the normal composting process to an early mature stage. Temperature, aeration; and moisture are monitored and controlled.
1.3.1 This method can determine biodegradation at levels of the plastic commonly expected in municipal solid waste.
1.4 These test methods require that the target component of the plastic material be synthesized using the radioactive isotope carbon-14. Depending upon the objective, either a portion of the components of the plastic or all of the carbon can be uniformly labeled with carbon-14. The test method will determine how that labeled portion will be metabolized and biologically oxidized by the microorganisms in the system tested.
1.5 These test methods can be applied to any carbon-14 labeled compound as well as for plastic materials that have been formulated to biodegrade in a natural aerobic environment.
1.6 The synthesis and preparation of the radiolabled plastic is beyond the scope of these methods. Carbon-14 labeled polymers may be purchased from a number of commercial labs.
1.7 There are no ISO test methods that are equivalent to the test methods in this standard.
1.8 The safety problems associated with compost and radioactivity are not addressed in this standard. It is the responsibility of the user of this standard to establish appropriate safety and health practices. It is also incumbent on the user to conform to all the regulatory requirements, specifically those that relate to the use of open radioactive sources.
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.
WITHDRAWN RATIONALE
These test methods directly determine the rate and degree of biological oxidation of carbon in plastic materials when placed in a composting environment containing simulated municipal solid waste or an aqueous environment under laboratory conditions.
Formerly under the jurisdiction of Committee D20 on Plastics, these test methods were withdrawn in January 2016 in accordance with section 10.6.3 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D6340 − 98(Reapproved 2007)
Standard Test Methods for
Determining Aerobic Biodegradation of Radiolabeled Plastic
Materials in an Aqueous or Compost Environment
This standard is issued under the fixed designation D6340; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.7 There are no ISO test methods that are equivalent to the
test methods in this standard.
1.1 These test methods directly determine the rate and
degree of biological oxidation of carbon in plastic materials 1.8 The safety problems associated with compost and radio-
when placed in a composting environment containing simu- activity are not addressed in this standard. It is the responsi-
lated municipal solid waste or an aqueous environment under bility of the user of this standard to establish appropriate safety
laboratory conditions. and health practices. It is also incumbent on the user to
conform to all the regulatory requirements, specifically those
1.2 Test MethodAutilizes a mixed culture derived from the
that relate to the use of open radioactive sources.
target environment (waste water, sewage sludge, compost
1.9 This standard does not purport to address all of the
eluant, and other environmental sources). Temperature,
safety concerns, if any, associated with its use. It is the
mixing, and aeration are monitored and controlled.
responsibility of the user of this standard to establish appro-
1.2.1 This method has the sensitivity to determine biodeg-
priate safety and health practices and determine the applica-
radation at concentrations commonly found in these environ-
bility of regulatory limitations prior to use.
ments.
1.3 Test Method B starts with fresh compost and proceeds
2. Referenced Documents
through the normal composting process to an early mature
2.1 ASTM Standards:
stage. Temperature, aeration; and moisture are monitored and
D883 Terminology Relating to Plastics
controlled.
D5209 Test Method for Determining the Aerobic Biodegra-
1.3.1 This method can determine biodegradation at levels of
dation of Plastic Materials in the Presence of Municipal
the plastic commonly expected in municipal solid waste.
Sewage Sludge (Withdrawn 2001)
1.4 These test methods require that the target component of
D5296 Test Method for Molecular Weight Averages and
theplasticmaterialbesynthesizedusingtheradioactiveisotope
Molecular Weight Distribution of Polystyrene by High
carbon-14. Depending upon the objective, either a portion of
Performance Size-Exclusion Chromatography
the components of the plastic or all of the carbon can be
D5338 Test Method for Determining Aerobic Biodegrada-
uniformly labeled with carbon-14. The test method will deter-
tion of Plastic Materials Under Controlled Composting
mine how that labeled portion will be metabolized and bio-
Conditions, Incorporating Thermophilic Temperatures
logically oxidized by the microorganisms in the system tested.
D5512 Practice for Exposing Plastics to a Simulated Com-
post Environment Using an Externally Heated Reactor
1.5 These test methods can be applied to any carbon-14
(Withdrawn 2002)
labeled compound as well as for plastic materials that have
been formulated to biodegrade in a natural aerobic environ-
3. Terminology
ment.
3.1 Definitions—For definitions of terms used in these test
1.6 The synthesis and preparation of the radiolabled plastic
methods as they relate to composting, see Terminology D883.
is beyond the scope of these methods. Carbon-14 labeled
3.1.1 specific activity, SA, n—refers to the quantity of
polymers may be purchased from a number of commercial
radioactivity per mass unit of compound (polymer, etc.), that is
labs.
dpmh%.
1 2
ThesetestmethodsareunderthejurisdictionofCommitteeD20onPlasticsand For referenced ASTM standards, visit the ASTM website, www.astm.org, or
are the direct responsibility of Subcommittee D20.96 on Environmentally Degrad- contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
able Plastics and Biobased Products. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved May 1, 2007. Published June 2007. Originally the ASTM website.
approved in 1998. Last previous edition approved in 1998 as D6340 - 98. DOI: The last approved version of this historical standard is referenced on
10.1520/D6340-98R07. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6340 − 98 (2007)
3.2 Acronyms: 5.3 Thesemethodsprovidebiodegradationdataatuselevels
3.2.1 Bq, n—becquerel; SI unit where 1 curie of the plastic in a full cycle composting process or an aqueous
(Ci) = 3.7 · 10 Bq. system.
3.2.2 dpm, n—disintegrations per minute, used to measure
6. Apparatus
the quantity of radioactivity.
3.2.2.1 Discussion—The measure dpm is derived from
6.1 Liquid Culture Apparatus:
counts per minute (cpm) where dpm = cmp-bkgd⁄counting
6.1.1 Fig. 1 is a diagrammatic representation of a single unit
efficiency. There are 2.2 · 10 dpm/µCi.
for measuring the carbon-14 carbon dioxide (CO ) production
3.2.3 mCi, n—millicurie;1/1000thofacurie(standardunit).
from the biodegradation of a labeled polymer in aqueous
culture. It consists of a fine needle valve for the sensitive
3.2.4 µCi, n—microcurie; 1/1000th of a millicurie.
controlofoxygenflow,awaterandcultureflaskinacontrolled
3.2.5 MSW, n—municipal solid waste (organic matter).
temperature environment, a trap to remove water from the gas
streamandtoinsurethecarbonmonoxide(CO)staysinthegas
4. Summary of Test Method
phase, and a CO absorption column: Periodic CO production
2 2
4.1 Test Method A involves the characterization of the test
over a chosen period of time can be sampled by collecting the
material,thepreparationofthenaturalmixedcultureinoculum,
CO absorbent from the column at the end of each period by
the control of the culture environment, the collection and
hand, or by automating the CO collection.
measurement of radioactive carbon dioxide (CO ) over time,
6.1.2 Fig. 2 illustrates an eight-unit system with a semi-
and the calculation and interpretation of the results.The results
automated CO collection system based on a timed, automated
may be compared to those obtained from Test Method D5209.
six-way valve. The gas effluent from the culture flask and acid
4.2 Test Method B involves the characterization of the test
trap is continuously passed through an absorption column and
material, the preparation of the compost matrix, the control of
periodically switched to the next column. Just before the sixth
the composting process, the collection and measurement of
column is due to switch, the five columns are drained and
radioactive CO over time, and the calculation and interpreta-
2 refilled. Soon after the sixth column switches, it is drained and
tion of the results. The results may be compared to those
refilled.
obtained from Practice D5512 as well as Test Method D5338.
6.1.3 Fig. 3 represents a single unit from a fully automated
CO collection system where two absorption columns are
5. Significance and Use
alternately used to capture the CO . While one column is
5.1 These test methods can provide direct and unequivocal
collecting CO from the effluent, the other is drained into a
evidence of aerobic biodegradability. This requires that the
scintillation vial, scintillation cocktail is added to the vial, and
radiochemical purity of the plastic is verified using Test
the column is refilled with the CO absorbent automatically.
Method D5296.
6.1.4 Fig. 4 is a diagrammatic representation of a sixteen-
5.2 These methods also provide the opportunity to deter- unit, fully automated system. The system is controlled by a
mine the rate of biological oxidation in a complete composting personal computer and an 1/0 microprocessor. Valves and
environment or aqueous environment by frequent periodic metering pumps are powered by electronically-controlled
sampling of carbon dioxide. power supplies and relays. Reservoirs of CO absorbent and
14 14
FIG. 1 Single Unit for Measuring CCO Production from the Biodegradation of a C-Labeled Polymer
D6340 − 98 (2007)
FIG. 2 Semiautomated CCO Collection System for Eight Units Over Six Sampling Periods
scintillation cocktail serve all sixteen units. The scintillation The shaft is connected to a motor that turns the shaft at rate of
vials are in a rack that positions the vials for each sampling about 6 r/min. The mixing motion is designed to mix, break up
period. clumps and convey the compost upward. The resultant action
6.1.5 Alternative apparatus can be used if it has the capa- tends to circulate the compost in the composting vessel and
bility of maintaining the appropriate temperature, controlling maintains an even flow of air through the compost.
the oxygen flow, humidification of gas flow, and complete
6.2.3 As air exits the composting vessel, it passes through a
collection of CO .
checkvalveandthenproceedsthroughasulfuricacidtrap.The
6.1.6 Alternate apparatus can be manually operated or
trap dehydrates the air and insures that the CO stays in the gas
controlled by computer interface.
phase.
6.2.4 The air then passes into a glass column filled with
6.2 Composting Apparatus:
glass helixes and a commercial CO absorber, methoxyethyl
6.2.1 Fig. 5 is a diagrammatic representation of the radio-
amine. The glass helixes break up the gas bubbles and provide
chemical composting apparatus. The radiochemical compost-
greater surface area for the absorption (scrubbing) of CO .
ing apparatus consists of a glass composting vessel capped by
an inert plastic surface, a controlled humidified air flow, a 6.2.5 The column is jacketed (has an outer glass chamber)
controlledtemperaturechamber,asulfuricacidtrap,andaCO
where a refrigerant (propylene glycol) is circulated.
absorption column.
6.2.6 A liquid scintillation counter, capable of counting the
6.2.2 The composting vessel is a 1-L borosilicate glass
low-energy beta emitted by the radioactive isotope carbon-14
reactionkettlewithaglassflangetooledtoreceivean“O”ring,
is used to measure the quantity of radioactivity in the trapped
clamped against an inert plastic surface. Pressurized air,
CO . An instrument that can automatically measure counting
controlled by a needle valve, is passed through a flow meter
efficiency and correct for quenching is preferred.
and then either through a water trap, maintained at the same
6.2.7 It is important to test the system for leaks and insure
temperature as the compost, or directly to the compost (25 6
that the radioactive CO does not escape from the apparatus
3cc/min).Thecompostingvesselisfittedwithacentralhollow
both for accurate results and safety of personnel.
stainless steel shaft that protrudes through a perforated dis-
6.2.8 Vent columns to a radiochemical hood.
tributor plate at the bottom of the vessel (Fig. 5). The air is
6.2.9 Place check valves, that will allow the air flow to
passed down the shaft to the space below the distributor plate
travelinonlyonedirection,betweenthetestflasksandtheacid
and then passes up through the compost to the top of the
and between the acid and absorber.
compost where it exits from the vessel.The shaft contains rods
projecting perpendicular from the shaft in a radiating fashion. 6.3 Alternate Composting Apparatus:
D6340 − 98 (2007)
(MSW) or woody compost, or obtained from an active munici-
pal solid waste or yard waste composting center.
7.1.1 Compost, designed to stimulate municipal solid waste
(MSW)organicmatter,ispreparedbycombiningthefollowing
materials (on a dry matter basis): alfalfa meal, 35.7 %; shred-
ded newspaper, 27.2 %; garden soil, 13.2 %; poplar sawdust,
10.4 %; cottonseed meal, 6.4 %; cow manure, 1.6 %; calcium
carbonate; 5.3 %; sodium bicarbonate, 0.2 %. The mixture is
designedtocontainthebiochemicalingredientsfoundinMSW
(lignified cellulose (newspaper, poplar sawdust and alfalfa
meal), protein (cottonseed meal and alfalfa meal), natural
inoculum (garden soil and cow manure); soluble carbohydrates
and buffering capacity sufficient to maintain a neutral to
slightly basic pH). The particle size of the components of the
compost mix are sized to pass through a 6-mm screen.
Moisture content should be adjusted (see 7.2)to55to60%for
testing.
7.1.2 An alternate compost (used to simulate yard compost-
ing activities) was used in an ASTM-ISR study and has the
following composition on a dry matter basis (made up to 55 to
60 % moisture for testing): wood chips (brush), 41.4 %;
chapped leaves, 25.4 %; grass clippings, 25.8 %; aged
compost, 7.3 %. Different compost preparations can produce
different rates of biodegradation. A yard and garden waste
compost can, with certain plastics, result in slower rates of
degradation.
7.2 The compost is made up to 55 to 60 % moisture by
measuringthemoisturecontentofeachcomponent,calculating
the moisture content of the mix, and adding water to bring the
mix to near target moisture percentage. The moisture content
FIG. 3 Single Unit from an Automated CCO Collection System
(V = valve and MP = metering pump)
canbecheckedbytakingasampleofthecompost,weighingit,
drying it, reweighing it, and calculating the moisture from the
difference in weight. Water can then be added as needed.
During the experiment, testing of the moisture content should
6.3.1 Alternative compost apparatus can be used if it con-
be checked weekly and maintained at 55 to 60 % by humidi-
forms to the following requirements:
fying (bubbling the air through water) the air as needed.
6.3.1.1 Although compost vessels can be larger than 1-L, it
isgenerallynotpracticaltoexceed1-L,duetothelargevolume
7.3 Liquid culture inoculum are prepared from the target
of CO that is produced and must be completely absorbed.
aqueous environment. They can be used directly, that is,
6.3.1.2 The compost temperature must be controlled.
sewage sludge or waste water treatment sludge, or eluant from
6.3.1.3 The air supply flow must be controlled and humidi-
compost, or they can be enriched by growing the mixed culture
fied.
on the carbon source of interest.
6.3.1.4 The air must be stripped of moisture prior to
7.4 Media used for liquid culture is related to the environ-
scrubbing to eliminate the two phases that occur when the
ment being simulated. For waste water or sewage sludge, a
scintillation cocktail is added to CO absorber that has accu-
limited basal me
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