ASTM G29-96

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: G 29 – 96
Standard Practice for
Determining Algal Resistance of Plastic Films
This standard is issued under the fixed designation G 29; 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
1.1 This practice covers the determination of the suscepti-
bility of plastic films to the attachment and proliferation of
surface-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 information
only.
1.3 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 appro-
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
2. Summary of Practice
2.1 In this practice, test strips of plastic film are suspended
in glass jars maintained at room temperature. The test strips are
exposed to fluorescent light and in direct contact with a
standardized inoculum of the filamentous blue-green alga
Oscillatoria in culture medium. The sample test jars are
reinoculated with fresh alga every second or third day. A
control using untreated plastic film is used as a basis of
FIG. 1 Propagation Tank
comparison. The inoculum is prepared with the help of a
propagation apparatus made from a small fish tank. The test is 4.1.1 A small fish tank (10 gal) is used to contain a
terminated at the end of two weeks, or whenever the test film
simulated cooling tower, made of redwood slats, over which
shows dense algal growth. culture medium is recirculated through a plastic tube with holes
punched in the bottom. This design was developed in order to
3. Significance and Use
provide ideal conditions for propagation of the algae that serve
3.1 Bodies of water, such as swimming pools, artificial
as inocula for each test. Three redwood slats are joined by two
ponds, and irrigation ditches often are lined with plastic films.
supports in such a way that water cascades over each slat in
Algae tend to grow in such bodies of water under the proper
turn from a distributor tube above the upper slat. A small, fully
atmospheric conditions, and they can produce slimy and
immersed recirculating pump rests on the bottom of the tank
unsightly deposits on the film. The method described herein is
and operates continuously to deliver the tank contents to the
useful in evaluating the degree and permanency of protection
distributor tube. The light required for algal propagation is
against surface growth of algae afforded by various additives
provided by a 100-W bulb placed 300 mm (12 in.) away from
incorporated in the film.
the redwood slats. A timing device turns the light on for 12 h
each day.
4. Apparatus
4.1.2 The propagation tank, that is used as the permanent
4.1 Propagation Tank (see Fig. 1):
source of inoculum, is filled to approximately one-third capac-
ity with the culture medium. Heavy growth of Oscillatoria
rapidly develops on the redwood tower and, at different phases,
This practice is under the jurisdiction of ASTM Committee G-3 on Durability
this growth appears light green, dark green, or black.
of Nonmetallic Materialsand is the direct responsibility of Subcommittee G03.04 on
Biological Deterioration.
Current edition approved June 10, 1996. Published October 1996. Originally Model 1 MA manufactured by the Little Giant Corp., 3800 N. Tulsa Ave.,
published as G 29 – 71 T. Last previous edition G 29 – 90. Oklahoma City, OK 73107, has been found suitable for this purpose.
2 4
The redwood tower should be soaked in water before use, until the water is Culture medium in the propagation tank is discarded, and the tank is refilled
colorless. Water is changed daily. with fresh medium at monthly intervals.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
G29
4.2 Test Chambers (see Fig. 2): 5.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean distilled water or water of
equal purity.
5.3 Culture Medium for Propagation Apparatus—Prepare
this medium by dissolving in 15 L of water the designated
amounts of the following reagents:
Arnon’s trace metal solution (see Note 1) 15 mL
Ethylenediamine tetraacetic acid disodium salt 0.04 g
Ferric ammonium citrate 0.85 g
Magnesium sulfate (MgSO ·7H O) 10.0 g
4 2
Potassium acid phosphate (K HPO ) 12.3 g
2 4
Potassium nitrate (KNO ) 12.1 g
Sodium citrate 2.0 g
Sulfuric acid, 10 % 10 mL
NOTE 1—Prepare this solution by combining the following reagents in
the amounts designated in 1 L of water:
Boric acid 2.86 g
Copper sulfate (CuSO ·5H O) 0.079 g
4 2
Manganese chloride (MnCl ·4H O) 1.18 g
2 2
Molybdic oxide (MoO ) 0.018 g
Zinc sulfate (ZnSO ·7H O) 0.22 g
4 2
5.3.1 Adjust to 7.2 to 7.5 pH range if necessary. The culture
medium need not be sterilized.
5.4 Culture Medium for Test Chambers— Dilute 50 mL of
the culture medium in 5.3 with 950 mL of tap water and place
this medium in the test chambers.
FIG. 2 Test Chambers
6. Test Specimens
4.2.1 One-litre (1-qt) wide-mouth glass jars, 170 mm (6 ⁄4 6.1 Select at random from the sample
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