ASTM D6006-97a(2003)

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An American National Standard
Designation:D6006–97a (Reapproved 2003)
Standard Guide for
Assessing Biodegradability of Hydraulic Fluids
This standard is issued under the fixed designation D 6006; 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 Carbon, Hydrogen, and Nitrogen in Petroleum Products
and Lubricants
1.1 This guide provides information to assist in planning a
D 5480 Test for Motor Oil Volatility by Gas Chromatogra-
laboratory test or series of tests from which may be inferred
phy
information about the biodegradability of an unused fully
D 5864 Test Method for Determining the Aerobic Aquatic
formulated hydraulic fluid in its original form. Biodegradabil-
Biodegradation of Lubricants and Their Components
ity is one of three characteristics which are assessed when
E 1196 TestMethodforDeterminingtheAnaerobicBiodeg-
judging the environmental impact of a hydraulic fluid. The
radation Potential of Organic Chemicals
other two characteristics are ecotoxicity and bioaccumulation.
2.2 ISO Standards:
1.2 Biodegradability may be considered by type of environ-
ISO 9439:1990 Technical Corrigendum I, Water Quali-
mental compartment: aerobic fresh water, aerobic marine,
ty–Evaluation in an Aqueous Medium of the Ultimate
aerobic soil, and anaerobic media. Test methods for aerobic
Biodegradability of Organic Compounds
fresh water, aerobic soil and anaerobic media have been
ISO 4259:1992(E) Petroleum Products–Determination and
developed that are appropriate for the concerns and needs of
Application of Precision Data in Relation to Methods of
testing in each compartment.
Test
1.3 This guide addresses releases to the environment that
2.3 OECD Standards:
are incidental to the use of a hydraulic fluid but is not intended
OECD 301B (the Modified Sturm Test) Guidelines for
to cover situations of major, accidental release. The tests
Testing Chemicals
discussed in this guide take a minimum of three to four weeks.
OECD 301F (the Manometric Respirometry Test) Guide-
Therefore, issues relating to the biodegradability of hydraulic
lines for Testing of Chemicals
fluid are more effectively addressed before the fluid is used,
and thus before incidental release may occur. Nothing in this
3. Terminology
guide should be taken to relieve the user of the responsibility
3.1 Definitions:
to properly use and dispose of hydraulic fluids.
3.1.1 aerobic, adj—1. taking place in the presence of
1.4 This standard does not purport to address all of the
oxygen; 2. living or active in the presence of oxygen.
safety concerns, if any, associated with its use. It is the
3.1.2 anaerobic, adj—1. taking place in the absence of
responsibility of the user of this standard to establish appro-
oxygen; 2. living or active in the absence of oxygen.
priate safety and health practices and determine the applica-
3.1.3 biodegradation, n—the process of chemical break-
bility of regulatory limitations prior to use.
down or transformation of a substance caused by organisms or
2. Referenced Documents their enzymes.
3.1.3.1 Discussion—Biodegradation is only one mechanism
2.1 ASTM Standards:
by which materials are transformed in the environment.
D 5210 Test Method for Determining the Anaerobic Bio-
3.1.4 biomass, n—any material, excluding fossil fuels,
degradation of Plastic Materials in the Presence of Mu-
which is or was a living organism or component of a living
nicipal Sewage Sludge
organism.
D 5291 Test Methods for Instrumental Determination of
3.1.5 blank, n—in biodegradability testing, a test system
containingallsystemcomponentswiththeexceptionofthetest
substance.
This guide is under the jurisdiction of ASTM Committee D02 on Petroleum
3.1.6 environmental compartment, n—a subdivision of the
Products and Lubricants and is the direct responsibility of Subcommittee D02.12 on
environment based on physical or chemical properties, or both.
Environmental Standards for Lubricants.
Current edition approved Nov. 1, 2003. Published November 2003. Originally
approved in 1996. Last previous edition approved in 1997 as D 6006–97a.
2 3
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D6006–97a (2003)
3.1.6.1 Discussion—Examples of environmental compart- vantages of several of the biodegradation tests frequently used
mentsareaerobicfreshwater,aerobicmarine,andaerobicsoil. for hydraulic fluids (Section 6).
The results of test procedures may be applied to environmental
5. Significance and Use
compartments but the test systems do not constitute an envi-
ronmental compartment.
5.1 This guide discusses ways to assess the likelihood that a
3.1.7 inoculum, n—spores, bacteria, single celled organ- hydraulic fluid will undergo biodegradation if it enters an
isms, or other live materials that are introduced into a test environment that is known to support biodegradation of some
medium. substances, for example the material used as the positive
3.1.8 preadaptation, n—the incubation of an inoculum in control in the test. The information can be used in making or
assessing claims of biodegradability of a fluid formula.
the presence of the test substance which is done prior to the
initiation of the test and under conditions similar to the test 5.2 Biodegradation occurs when a fluid interacts with the
environment, and so the extent of biodegradation is a function
conditions.
of both the chemical composition of the hydraulic fluid and the
3.1.8.1 Discussion—The aim of preadaptation is to improve
physical, chemical, and biological status of the environment at
the precision of the test method by decreasing variability in the
the time the fluid enters it. This guide cannot assist in judging
rate of biodegradation produced by the inoculum. Preadapta-
the status of a particular environment, so it is not meant to
tion may mimic the natural processes which cause changes in
provide standards for judging the persistence of a hydraulic
the microbial population of the inoculum leading to more rapid
fluid in any specific environment either natural or man-made.
biodegradation of the test substance, but it is not expected to
5.3 If any of the tests discussed in this guide gives a high
change the final degree of biodegradation.
result, it implies that the hydraulic fluid will biodegrade and
3.1.9 primary biodegradation, n—degradation of the test
will not persist in the environmental compartment being
substance resulting in a change in its physical or chemical
considered. If a low result is obtained, it does not mean
properties, or both.
necessarily that the substance will not biodegrade in the
3.1.10 primary biodegradation test, n—atestwhichfollows
environment, but does mean that further testing is required if a
the disappearance of a test substance by measuring some
claim of biodegradability is to be made. Such testing may
attribute of the substance.
include,butisnotlimitedto,othertestsmentionedinthisguide
3.1.10.1 Discussion—The extent to which the results of a
orsimulationtestsforaparticularenvironmentalcompartment.
primary biodegradation test correspond to the biological con-
version of the test substance will depend on the attribute which
6. Test Methods
is being measured.
6.1 Aerobic Fresh Water Environment—The most com-
3.1.11 sonication, n—the act of subjecting a material to the
monly performed tests cover aerobic biodegradation in fresh
shearing forces of high-frequency sound waves.
water. The tests conducted for this compartment may be
3.1.11.1 Discussion—Sonication of a two phase liquid sys-
ultimate biodegradation tests measuring CO production or
tem may result in the dispersal of one phase as fine droplets in 2
primary biodegradation tests measuring the disappearance of
the other phase.
the test fluid. The test medium is based on high-grade,
3.1.12 ultimate biodegradation, n—degradation achieved
carbon-free water. Some salts will be included as necessary for
when a substance is totally utilized by microorganisms result-
maintenance of solution pH and provision of trace minerals
ing in the production of carbon dioxide (and possibly methane
necessary for microbial life.
in the case of anaerobic biodegradation), water, inorganic
6.1.1 The majority of ultimate biodegradation tests measure
compounds, and new microbial cellular constituents (biomass
produced CO . Examples of test procedures for ultimate
or secretions, or both).
biodegradability in an aerobic aquatic environment are: the
3.1.13 ultimate biodegradation test, n—a test which esti-
Modified Sturm Test (OECD 301B); the Manometric
mates the extent to which the carbon in a product is converted
Respirometry Test (OECD 301F); the U.S. EPA Aerobic
to CO or methane, either directly, by measuring the produc-
Aquatic Biodegradation Test, which also is called the EPA
tion of CO or methane, or, in the case of aerobic biodegrada-
Shake Flask Test and was derived from the Gledhill Test (1);
tion, indirectly by measuring the consumption of O .
Test Method D 5864; and the ISO Test 9439:1990. With the
3.1.13.1 Discussion—The measurement of new biomass
exception of Test Method D 5864, these tests were originally
usually is not attempted.
designed for water-soluble pure compounds and so the test
procedures allow some procedural options that are not suitable
4. Summary of Guide
for water-insoluble substances, such as addition of the test
4.1 This guide gives two kinds of information which relate
substance in an aqueous solution or calculation, rather than
to testing of hydraulic fluids for biodegradability. First, it gives
measurement, of carbon content. In other tests, such as the
informationofageneralnaturerelatingtobiodegradability.For
Manometric Respirometry Test, oxygen consumption is mea-
example, it includes definitions of terms not traditionally used
sured as a surrogate for CO production. Oxygen consumption
byusersorproducersofhydraulicfluids(Section3)andabrief
is not a direct measure of ultimate biodegradation but is
discussion of some of the technical issues which are common
to most biodegradability tests when they are applied to
hydraulic fluids (Section 7). Second, the guide gives more
The boldface numbers in parentheses refer to the list of references at the end of
specific information on the methods, advantages, and disad- this standard.
D6006–97a (2003)
expected to correlate closely with it. The procedures listed are without drastically changing its physical properties, so a sterile
screeningtestssuitableforlaboratoryevaluationofthehydrau- starting soil similar in function to high-grade, carbon-free
licfluid.Althoughallthetestsreferredtoabovespecifythatthe water, is not possible. The inoculum for these test procedures
length of the test is 28 days, a high level of biodegradation in is typically the microbial community that naturally resides in
longer time frames can be taken as evidence that the hydraulic the soil sample used for the test. No further augmentation
fluid is ultimately biodegradable and nonpersistent in fresh generallyisrequired.Thesourcesofthesoilsamplesshouldbe
water. reported with test results.Alow result in any soil test may not
mean that the hydraulic fluid will persist in an aerobic soil
6.1.1.1 If the biodegradability of a hydraulic fluid with a
environment, but does mean that more testing is required.
nonnegligible vapor pressure is measured in any one of these
tests, except the OECD 301F, a false negative may result. The 6.3.1 With modifications, published tests for aerobic bio-
degradation in soils could be suitable for hydraulic fluids, but
hydraulic fluid could vaporize from the test solution before
conversion to CO . In this case a biodegradable fluid would none of the available standardized tests can be used as written.
In some cases only minor changes are necessary, such as
have a low measured percent theoretical CO . If the aerobic
aquatic biodegradability of a volatile hydraulic fluid is to be development of a method for introduction of a water insoluble
substance. Tests of soil biodegradation that currently are
measured, the OECD 301F test should be used.
available fall into three categories.
6.1.2 Tests for primary biodegradation must be designed for
specific classes of test substances. The results of a primary 6.3.1.1 First are those tests that follow CO production by
chemical means. An example of this kind of test has been
biodegradation test should not be considered equivalent to or
substitutable for the results of an ultimate biodegradation test. published by the U.S. FDA (8). These tests are suitable for
adaptation to assess the biodegradability of a hydraulic fluid in
6.1.2.1 The most commonly performed primary biodegra-
aerobic soils. Such adaptation may include different sample
dation test for lubricants is the CEC L-33-A-94 test, developed
handling procedures or changes in sample concentration. The
by the Coordinating European Council in the early 1980s and
U.S. FDA test is not suitable for testing volatile hydraulic
approved by the CEC in 1993. This test, which was called the
fluids.
CEC L-33-T-82 test prior to approval, measures the IR
absorption spectrum of saturated carbons found in the test 6.3.1.2 Second are those that use test substances labeled
with radioactive tracers and follow the production of radioac-
materials. It was designed specifically for two-stroke outboard
engine lubricants; however, it is frequently used for measuring tive CO , for example OECD 304A (6). These tests have the
advantage of allowing the use of very low concentrations of
the biodegradability of other lubricants. It is suitable for
measuring the primary biodegradation of hydraulic fluids if test substance, but are inappropriate for hydraulic fluids be-
cause hydraulic fluids are complex mixtures of many chemical
they have methylene hydrogens (-CH -) in their chemical
structures. CEC results for some materials have been found to compounds, so the selection of an appropriate site for the label
is impossible (7).
correlate with the results of ultimate biodegradation te
...