ASTM_D_7473_-_12.pdf

Designation:D747312Standard Test Method forWeight Attrition of Plastic Materials in the MarineEnvironment by Open System Aquarium Incubations1This standard is issued under the fixed designation D7473;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year 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.Scope1.1 This test method is used to determine the weight loss asa function of time of non-floating plastic materials(includingformulation additives),when incubated under changing,open,marine aquarium conditions,which is representative of aquaticenvironments near the coasts and near the bottom of a body ofwater in the absence of sunlight,particularly UV and visibleportions of the spectrum.The goal of this test is to obtain datathat will predict real world experiences based on the extent andrate of biodegradation data of the same materials obtained fromthe laboratory Test Method D6691.The aquarium incubatedfilms are examined for visual degradation and dry weight lossover time.This test is not a replacement to Test Method D6691,but rather an additionalASTM method for weight attrition.Thestandard addresses weight loss of the plastics in a marineenvironment and cannot be used for demonstrating biodegra-dation for which Specification D7081 needs to be used.1.2 Plastic film pieces of known size and thickness are usedat levels so as not to exceed the availability of micronutrientsessential for and therefore limit the microbial biodegradationprocess.1.3 The aquarium incubation test method allows represen-tative indigenous microorganisms present in seawater andmarine sediment to be enriched for and carry out the biodeg-radation.It is recommended that the test be carried out in thegeographical vicinity(latitudinal area)where the test film islikely to be used and potentially disposed of in the marineenvironment if biodegradable criteria are met.TheseAquariumstudies are conducted in indoor environments,hence anysunlight-induced effects on degradation,or biodegradation,orboth,are not taken into account.1.4 Prior to conducting this aquarium test method(weightloss data)for the verification of biodegradability,Test MethodD6691 shall be run on the same materials to establish quanti-tative levels of the plastic organic carbon oxidation and levelsof carbon dioxide recovered there from.If Test Method D6691achieves 30%mineralization,then apply this Aquarium testand perform it.If the results from Test Method D6691 do notachieve 30%mineralization,then aquarium incubation testingneed not be done and the material shall be considered non-biodegradable in the marine environment.1.5 This test by itself shall not be used as the basis forclaims,such as“Biodegradable in Marine Environments”sinceit is only a weight loss test method.1.6 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE1There is no known ISO equivalent to this standard.2.Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD6691 Test Method for Determining Aerobic Biodegrada-tion of Plastic Materials in the Marine Environment by aDefined Microbial Consortium or Natural Sea WaterInoculumD7081 Specification for Non-Floating Biodegradable Plas-tics in the Marine Environment3.Terminology3.1 DefinitionsDefinitions of terms applying to this testmethod appear in Terminology D883.3.2 Definitions of Terms Specific to This Standard:3.2.1 absence of lightabsence of electromagnetic radia-tion with the focus on visible and ultraviolet portions of thespectrum of sunlight or other light with similar wavelengthfrequencies from artificial sources.3.2.2 natural seawater(NSW)seawater unamended withany additives.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.96 on EnvironmentallyDegradable Plastics and Biobased Products.Current edition approved May 1,2012.Published June 2012.DOI:10.1520/D747312.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.3 indigenous microbesthose microbes naturally occur-ring in a seawater or sediment sample.3.2.4 mesophilictemperature range from approximately20 to 40C over which microorganisms adapted to moderateconditions maintain active metabolic rates.3.2.5 psychrophilictemperature range from approximately2 to 20C over which microorganisms adapted to cold