1、Designation: D5988 12D5988 18Standard Test Method forDetermining Aerobic Biodegradation of Plastic Materials inSoil1This standard is issued under the fixed designation D5988; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers determination under laboratory conditions of the degree and rate of aerobic biodegradatio
3、n of plasticmaterials, 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 aerobicenvironment.1.3 This test method is designed to be applicable to all plastic materials that
4、 are not inhibitory to the bacteria and fungi presentin 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 an
5、d referencesamples 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. I
6、t is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use. A specific hazard statement is given in Section 8.1.7 This ASTM test method is equivalent to IS
7、O 17556.1.8 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barrie
8、rs to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D425 Test Method for Centrifuge Moisture Equivalent of SoilsD618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD1193 Specification for Reagent WaterD1293 Test Methods for pH of WaterD2974 Test
9、 Methods for Moisture, Ash, and Organic Matter of Peat and Other Organic SoilsD2980 Test Method for Saturated Density, Moisture-Holding Capacity, and Porosity of Saturated Peat MaterialsD2989 Test Method for Acidity-Alkalinity of Halogenated Organic Solvents and Their AdmixturesD4129 Test Method for
10、 Total and Organic Carbon in Water by High Temperature Oxidation and by Coulometric DetectionD4972 Test Method for pH of SoilsD5338 Test Method for Determining Aerobic Biodegradation of Plastic Materials Under Controlled Composting Conditions,Incorporating Thermophilic TemperaturesD5511 Test Method
11、for Determining Anaerobic Biodegradation of Plastic Materials Under High-Solids Anaerobic-DigestionConditions1 This test method is under the jurisdiction ofASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.96 on Environmentally DegradablePlastics and Biobased Produc
12、ts.Current edition approved May 1, 2012April 1, 2018. Published June 2012April 2018. Originally approved in 1996. Last previous edition approved in 20032012 asD5988 - 03.D5988 - 12. DOI: 10.1520/D5988-12.10.1520/D5988-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contact
13、ASTM Customer Service at serviceastm.org. ForAnnual Book ofASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been mad
14、e to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A S
15、ummary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.2 APHA-AWWA-WPCF Standards:32540 D Total Suspended Solids Dried at 103105C2540 G Total, Fixed, and Volatile Solids in Solid
16、s and Semi-Solid Samples2.3 ISO Standard:4ISO 11261 Soil QualityDetermination of Total NitrogenModified Kjeldahl MethodISO 17556 PlasticsDetermination of the Ultimate Aerobic Biodegradability of Plastic Materials in Soil by Measuring theOxygen Demand in a Respirometer or the Amount of Carbon Dioxide
17、 Evolved3. Terminology3.1 DefinitionsDefinitions of terms applicable to this test method appear in Terminology D883.4. Summary of Test Method4.1 The test method described consists of the selection of plastic material for the determination of aerobic biodegradability,obtaining soil as a matrix and so
18、urce of inoculum, exposing the plastic material to the soil, measuring the carbon dioxide evolvedby the microorganisms as a function of time, and assessing the degree of biodegradability.4.2 The CO2 production measured for a material, expressed as a fraction of the measured or calculated carbon cont
19、ent, isreported with respect to time, from which the degree of biodegradability is assessed.4.3 Alternatively, it is possible to determine the consumption of oxygen, or biochemical oxygen demand (BOD), for example,by measuring the amount of oxygen required to maintain a constant gas volume in the re
20、spirometer flask, or by measuring thechange in volume or pressure (or a combination of the two) either automatically or manually.The level of biodegradation expressedin percent is determined by comparing the BOD with the theoretical oxygen demand (ThOD). In using this alternative approach,however, t
21、he influence of possible nitrification processes on the BOD must be considered.5. Significance and Use5.1 The degree and rate of aerobic biodegradability of a plastic material in the environment determines the extent to which andtime period over which plastic materials are mineralized by soil microo
22、rganisms. Disposal is becoming a major issue with theincreasing use of plastics, and the results of this test method permit an estimation of the degree of biodegradability and the timeperiod over which plastics will remain in an aerobic soil environment. This test method determines the degree of aer
23、obicbiodegradation by measuring evolved carbon dioxide as a function of time that the plastic is exposed to soil.5.2 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 conten
24、t and oxygen availability, the biological activity is quiteconsiderable, although lower than other biologically active environments, such as activated sewage-sludge or compost.6. Apparatus6.1 Soil-Contact Incubation Apparatus (see Fig. 1; biometer flasks are also appropriate). Ensure that all glassw
25、are is thoroughlycleaned and, in particular, free from organic or toxic matter.3 Standard Methods for the Examination of Water and Wastewater, 17th Edition, 1989, Available from American Public Health Association (APHA), 1015 FifteenthStreet800 I St., NW, Washington, DC 20005.20001, http:/www.apha.o
26、rg.4 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.NOTE 1(1) Barium hydroxide solution or potassium hydroxide solution, (2) soil, (3) water, and (4) perforated plate.FIG. 1 Soil-Contact Incubation ApparatusD5988 1826.1.
27、1 Vessels, a set of vessels with approximately 2 to 4-L of internal volume with air-tight seal, such as 150-mm desiccators.Provide three vessels for soil only (known as “blanks” or “controls,” these vessels show the background activity of the soil), threevessels for a positive reference material (th
28、ese vessels show the viability of the soil microbial community), three vessels per testmaterial, and three vessels as technical controls. The technical controls contain only the absorbing solution and no soil. Theambient air which fills the headspace of all the vessels introduces carbon dioxide into
29、 the system. The technical controls allowaccounting for and subtracting this introduced carbon dioxide. Additionally, the technical controls indicate the air-tightness of thevessel system by showing possible infiltration of carbon dioxide into the sealed vessel.6.1.2 Beakers, sets of 150-mL and 100-
30、mL, equal in number to the soil incubation vessels.6.1.3 Perforated Plates or Other Support, a set to hold the beakers above the soil inside each vessel. The support must be madefrom a material that will not absorb carbon dioxide.6.1.4 Darkened Chamber or Cabinet, which allows selection of a tempera
31、ture between 20C to 28C, and allows maintainingthe selected temperature at 62C.6.2 Analytical Equipment:6.2.1 Analytical Instrument, to measure the total carbon content of the test specimen.6.2.2 Analytical Balance, to weigh the test specimen.6.2.3 Burette, 100 mL.6.2.4 Bench-Top Centrifuge, for moi
32、sture-holding capacity (MHC) determination.6.2.5 Oven, set to 104 6 1C for moisture determinations.6.2.6 Muffle Furnace, set to 550C for ash determinations.6.2.7 pH Meter.6.3 Alternatively, it is acceptable to use a flow-through apparatus or manometric apparatus as described in ISO 17566.7. Reagents
33、 and Materials7.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where suchspecifications are available.5 It is ac
34、ceptable to use other grades, provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy of the determination.7.2 Ammonium Phosphate, (NH4)2HPO4), 4.72 g/L.7.3 Barium Hydroxide Solution (0.025 N), prepared by dissolving 4.0 g anhy
35、drous Ba(OH)2/L of distilled water. Filter free ofsolid material, confirm normality by titration with standard acid, and store sealed as a clear solution to prevent absorption of CO2from the air. It is recommended that 5 to 20 Lbe prepared at a time when running a series of tests. When using Ba(OH)2
36、, however,care must be taken that a film of BaCO3 does not form on the surface of the solution in the beaker, which would inhibit CO2diffusion into the absorbing medium. Alternatively, it is acceptable to use potassium hydroxide solution (KOH, 0.5 N), preparedby dissolving 28 g of anhydrous KOH/L of
37、 distilled water and proceeding in the same way as for the Ba(OH)2.7.4 Hydrochloric Acid, 0.05 N HCl when using 0.025 N Ba(OH)2, or 0.25 N HCl when using 0.5 N KOH.8. Hazards8.1 This test method includes the use of hazardous chemicals. Avoid contact with chemicals and follow the manufacturersinstruc
38、tions and material safety data sheets.9. Soil9.1 Use natural, fertile soil collected from the surface layers of fields and forests. Make a laboratory mixture of equal parts (byweight) of soil samples obtained from at least three diverse locations (for example, an agricultural field, a forest, and a
39、pasture ormeadow). Taking soil from multiple and diverse locations will maximize biodiversity. It is advisable to avoid soils that have beenexposed to pollutants that cause significant perturbations of the microbial population. The soils are preferably used fresh from thefield to assure active micro
40、biota. Air-dried or frozen soils must be reactivated before use in this test. It is preferable to use fertilesoil classified as “sandy loam” in accordance with USDA classification, or “silty sand” in accordance with the German DINclassification.9.2 The sources of the soils must be reported (see 14.1
41、.1). Record the sampling site, its location, the presence of plants or crops,the sampling date, the sampling depth, and, if possible, the history such as details of fertilizer and pesticide application.9.3 Sieve the soil to less than 2-mm particle size, and remove obvious plant material, stones, or
42、other inert materials. Store thesoil in a sealed container at 4 6 1C for a maximum of one month.5 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar
43、Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D5988 1839.4 Analyze the soil for MHC by Test Method D425, Test Method D2980, or another analogous test method for MH
44、C or fieldcapacity.9.5 Determine the pH of the soil on a 5:1 (distilled water:soil) slurry using a glass combination electrode calibrated withstandard buffers, following the guidelines given in Test Method D1293. Alternatively, it is acceptable to determine the soil pH byTest Method D4972. The pH mu
45、st fall between 6.0 and 8.0. (Soil with a pH above 8.0 retains more of the CO2 evolved by themicroorganisms than a neutral soil, while a soil with a pH below 6.0 has the potential to contain an atypical microbial population.)9.6 Determine the moisture (total solidsdry solids) and ash (total solidsvo
46、latile solids) contents of the soil in accordancewith Test Method D2974 or APHA-AWWA-WPCF 2540 D and G, respectively.9.7 Determine total nitrogen in accordance with ISO 11261 or equivalent method.9.8 It is acceptable for the test matrix to be a mixture of natural soil, as described in 9.1, and matur
47、e compost, such as obtainedat the end of Test Method D5338, at a ratio of 1 g compost to 25 g soil, which corresponds to a typical application in agricultureof approximately 120 tons of compost per hectare of agricultural land (assuming 20 cm of soil depth and a bulk density of 1.5 Mgm3).10. Test Sp
48、ecimen10.1 Test specimens shall be of known weight and have sufficient carbon content to yield enough carbon dioxide that can bemeasured accurately by the trapping procedure described in this test method (see 11.7 and 11.9). Determine the carbon content ofthe test material by calculation or elementa
49、l analysis, in accordance with Test Method D4129.10.2 It is acceptable for test specimens to be in the form of films, pieces, fragments, powders, or formed articles, or in aqueoussolution, in accordance with Practice D618. It is recommended, but not required, to characterize any test specimens in the formof powders as to particle size distribution by sieve analysis.11. Procedure11.1 The test shall be performed in triplicate for each of the technical control, soil blank, positive reference material, and testmaterials (triplicate for each test material).11.2 Pl
