1、Designation: G29 16Standard Practice forDetermining Algal Resistance of Polymeric Films1This standard is issued under the fixed designation G29; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A number in
2、 parentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This practice covers the determination of the suscepti-bil
3、ity of polymeric films to the attachment and proliferation ofsurface-growing algae.1.2 The values in SI units are to be regarded as the standard.The inch-pound units given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associat
4、ed 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.2. Summary of Practice2.1 In this practice, test strips of polymeric film are sus-pended in glass jars m
5、aintained at room temperature. The teststrips are exposed to fluorescent light and in direct contact witha standardized inoculum of the filamentous blue-green algaOscillatoria in culture medium. The sample test jars arere-inoculated with fresh alga every second or third day. Acontrol using untreated
6、 polymeric film is used as a basis ofcomparison. The inoculum is prepared with the help of apropagation apparatus made from a small fish tank. The test isterminated at the end of two weeks, or whenever the untreatedcontrol shows dense algal growth.3. Significance and Use3.1 Bodies of water, such as
7、swimming pools, artificialponds, and irrigation ditches often are lined with polymericfilms. Algae tend to grow in such bodies of water under theproper atmospheric conditions, and they can produce slimy andunsightly deposits on the film. The method described herein isuseful in evaluating the degree
8、and permanency of protectionagainst surface growth of algae afforded by various additivesincorporated in the film.4. Apparatus4.1 Propagation Tank:4.1.1 A small fish tank (10 gal) is used to contain an algaepropagation system where culture medium is recirculatedthrough a polymeric tube with holes pu
9、nched in the bottomover the top of a polymeric mesh screen inside of the tank. Thisdesign was developed in order to provide ideal conditions forpropagation of the algae that serve as inocula for each test. Thepolymeric mesh is supported in such a way that water cascadesover the top from a distributo
10、r tube above. A small, fullyimmersed recirculating pump rests on the bottom of the tankand operates continuously to deliver the tank contents to thedistributor tube. The light required for algal propagation isprovided by a 100-W bulb placed 300 mm (12 in.) away fromthe polymeric mesh. A timing devic
11、e turns the light on for thedesired light cycle each day.4.1.2 The propagation tank that is used as the permanentsource of inoculum is filled to approximately one-third capac-ity with the culture medium. Heavy growth of Oscillatoriarapidly develops on the polymeric mesh screen and, at differentphase
12、s, this growth appears light green, dark green, or black.NOTE 1Culture medium in the propagation tank is discarded monthlyand replaced with fresh media.4.2 Test Chambers:4.2.1 One-litre (1-qt) wide-mouth glass jars, 170 mm(634 in.) high by 76 mm (3 in.) in inside diameter, orequivalent, serve as tes
13、t chambers wherein water containing aninoculum of the algal organisms and strips of the polymericfilm are maintained in contact.4.2.2 The jars in 4.2.1 are placed in a suitable glasscontainer, such as a 38-L (10-gal) fish tank that is illuminatedby four 20-W “cool white” fluorescent bulbs, arranged
14、two oneach long side of the tank, at the level of the growing algae inthe jars. The lamps are mounted on a bracket that holds theouter surface of the bulbs 25 mm (1 in.) from the wall of thetank. The tank is filled with water to within 25 mm (1 in.) of thetop of the exposure jars in order to create
15、uniform temperatureconditions for all jars.4.3 HomogenizerAny suitable commercial homogenizerfor preparing the algal inocula.1This practice is under the jurisdiction of ASTM Committee G03 on Weatheringand Durability and is the direct responsibility of Subcommittee G03.04 onBiological Deterioration.C
16、urrent edition approved Dec. 1, 2016. Published March 2017. Originallyapproved in 1971. Last previous edition approved in 2010 as G29 96 (2010). DOI:10.1520/G0029-16.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international st
17、andard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.15.
18、Reagents and Materials5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are avail
19、able.2Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean distilled water or water o
20、fequal purity.5.3 Culture Medium for Propagation ApparatusPreparethis medium by dissolving in 15 L of water the designatedamounts of the following reagents:Arnons trace metal solution (see Note 2) 15 mLEthylenediamine tetraacetic acid disodium salt 0.04 gFerric ammonium citrate 0.85 gMagnesium sulfa
21、te (MgSO47H2O) 10.0 gPotassium acid phosphate (K2HPO4) 12.3 gPotassium nitrate (KNO3) 12.1 gSodium citrate 2.0 gSulfuric acid, 10 % 10 mLNOTE 2Prepare this solution by combining the following reagents inthe order given in the amounts designated in 1 L of water:Boric acid 2.86 gCopper sulfate (CuSO45
22、H2O) 0.079 gManganese chloride (MnCl24H2O) 1.18 gMolybdic oxide (MoO3) 0.018 gZinc sulfate (ZnSO47H2O) 0.22 g5.3.1 BG 11 Medium for Cyanobacteria:stock solutiong/100 mlnutrient solutionmlNaNO315 10K2HPO4.3H2O0.4 10MgSO4.7H2O 0.75 10CaCl2 . 2H2O 0.36 10citric acid 0.06 10ferric ammonium citrate 0.06
23、10EDTA (dinatrium-salt) 0.01 10Na2CO30.2 10Trace mineral solutionA1de-ionized or distilled water 919AComposition of the Trace minerals solution (from Kuhl and Lorenzen 1964): Addto 1000 ml of de-ionized or distilled water:H3BO361.0 mgMnSO4.H2O 169.0 mgZnSO4.7H2O 287.0 mgCuSO4.5 H2O2.5(NH4)6Mo7O24.4H
24、2O 12.5 mg5.3.2 BG 11 Medium without sodium nitrate (BG11NaNO3):Prepare BG 11 medium without sodium nitrate (NaNO3) andadd 929 mL instead of 919 mL of water.5.3.3 Adjust to 7.2 to 7.5 pH range if necessary. Filtersterilization is recommended.5.4 Culture Medium for Test VesselsDilute 50 mL of thecult
25、ure medium in 5.3 with 950 mL of deionized or distilledwater and place this medium in the test vessels.6. Test Specimens6.1 Select at random from the sample sufficient film toprepare the required number of test specimens 25 mm by65 mm (1 in. by 212 in.).6.2 When possible, use untreated film, similar
26、 in all otherrespects to the treated film, for testing in the same manner asthe test specimens, in order to verify the viability of the testorganism. If this untreated viability control material fails toshow any abundant growth of the test organisms, consider thetest inconclusive and repeat it.7. Pr
27、ocedure7.1 Attachment of SpecimensSamples are suspended ineach test vessel by means of polymeric clips hooked over apolymeric or fiberglass rod extending over the test chambers.Additional means of suspension may be used as long as nobiologically active materials (for example, adhesives, cements)come
28、 in contact with the test specimens during submersion.7.2 Inoculation of Test VesselsRemove an area of growthabout 4 cm2(1 in.2) in area from the propagation tank and placein 500 mL of test chamber culture medium (see 5.4). Homog-enize until no discrete large particles can be seen. Then add100 mL of
29、 this inoculum to each test vessel containing either atest specimen or an untreated control, and fill the vessel withthe culture medium.7.3 IncubationStore the inoculated test chambers underlight/dark exposure, such as 12 h light, then under darkness for12 h, continually repeating this cycle. Every
30、second or thirdday remove each test vessel, place in a sink, and reinoculatewith 100 mL of the fully homogenized algae. Introduce theinoculum into the bottom of each test vessel, allowing the samevolume of old vessel water to flow over the top of the vessel.This is done in order to simulate the addi
31、tion of new water andthe continuous reinoculation that occurs under natural condi-tions.7.4 Termination of TestAt the end of two weeks, orwhenever untreated films show dense algal growth, remove thefilms from the test chambers and place them upon white filterpaper surfaces for examination.8. Interpr
32、etation of Results8.1 Describe the extent of growth upon each surface asfollows:TABLE Observed Growth on SpecimensNone 0Traces of growth (60 % to complete coverage) 49. Report9.1 Report the following information or as otherwise agreedupon between parties involved in the testing:9.1.1 The date, algal
33、 species used, incubation conditions,and sample identification,2Reagent Chemicals, American Chemical Society Specifications AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, B
34、DH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.G291629.1.2 The corresponding results of observations, including:dates; notation of any unusual occurrences; and the rating ofdegree of defacement, and9.1.
35、3 If an ASTM test method or practice is used forpreconditioning, all appropriate information as required by thattest method or practices must be reported.10. Precision and Bias10.1 A precision and bias statement cannot be made for thispractice at this time.ASTM International takes no position respec
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38、onal Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below
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