ASTM D6139 Aerobic Aquatic Biodegradation of Lubricants or Their Components
ASTM D6139 Standard Test Method for Determining the Aerobic Aquatic Biodegradation of Lubricants or Their Components Using the Gledhill Shake Flask
1. Scope
1.1 This test method covers the determination of the degree of aerobic aquatic biodegradation of fully formulated lubricants or their components on exposure to an inoculum under controlled laboratory conditions. This test method is an ultimate biodegradation test that measures carbon dioxide (CO2) evolution.
1.2 This test method is intended to specifically address the difficulties associated with testing water insoluble materials and complex mixtures such as are found in many lubricants.
1.3 This test method is designed to be applicable to all non volatile lubricants or lubricant components that are not toxic and not inhibitory at the test concentration to the organisms present in the inoculum.
1.4 This standard does not purport to address all the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use. Specific hazards are discussed in Section 10.
2. Referenced Documents
2.1 ASTM Standards:
D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
D1293 Test Methods for pH of Water
D4447 Guide for Disposal of Laboratory Chemicals and Samples
D5291 Test Methods for Instrumental Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants
D5864 Test Method for Determining Aerobic Aquatic Biodegradation of Lubricants or Their Components
E 943 Terminology Relating to Biological Effects and Environmental Fate
2.2 ISO Standard:
4259:1992(E) Petroleum Products - Determination and application of precision data in relation to methods of test
2.3 APHA Standards:
2540B Total Solids Dried at 103 - 105°C
9215 Heterotrophic Plate Count
3. Terminology
3.1 Definitions:
3.1.1 Definitions of terms applicable to this test method which are not described herein, appear in the Compilation of ASTM Standard Definitions (1990) or Terminology E 943.
3.1.2 activated sludge, n - the precipitated solid matter, consisting mainly of bacteria and other aquatic microorganisms, that is produced at a domestic wastewater treatment plant; activated sludge is used primarily in secondary sewage treatment to microbially oxidize dissolved organic matter in the effluent.
3.1.3 aerobic, adj. - (1) taking place in the presence of oxygen; (2) living or active in the presence of oxygen.
3.1.4 biodegradation, n - the process of chemical breakdown or transformation of a test material caused by organisms or their enzymes.
3.1.4.1 Discussion - Biodegradation is only one mechanism by which substances are removed from the environment.
3.1.5 biomass, n - any material, excluding fossil fuels, which is or was a living organism or component of a living organism.
3.1.6 blank, n - in biodegradability testing, a test system containing all system components with the exception of the test material.
3.1.7 inoculum, n - spores, bacteria, single celled organisms, or other live materials, that are introduced into a test medium.
3.1.8 lag phase, n - the period of diminished physiological activity and cell division following the addition of microorganisms to a new culture medium.
3.1.9 log phase, n - the period of growth of microorganisms during which cells divide at a positive constant rate.
3.1.10 mixed liquor, n - in sewage treatment, the contents of an aeration tank including the activated sludge mixed with primary effluent or the raw wastewater and return sludge.
3.1.11 pre-adaptation, n - the incubation of an inoculum in the presence of the test material which is done prior to the initiation of the test and under conditions similar to the test conditions.
3.1.11.1 Discussion - The aim of pre adaptation is to improve the precision of the test method by decreasing variability in the rate of biodegradation produced by the inoculum. Pre adaptation may mimic the natural processes which cause changes in the microbial population of the inoculum leading to a more rapid rate of biodegradation of the test material but is not expected to change the overall extent of biodegradation of the test material.
3.1.12 pre-condition, n - the pre-incubation of an inoculum under the conditions of the test in the absence of the test material.
3.1.13 supernatant, n - the liquid above settled solids.
3.1.14 suspended solids (of activated sludge or other inoculum samples), n - solids present in activated sludge or inoculum samples that are not removed by settling under specified conditions.
3.1.15 theoretical carbon dioxide (ThCO2), n - the amount of CO2 which could theoretically be produced from the complete biological oxidation of all of the carbon in a test material.
3.1.16 ultimate biodegradation, n - degradation achieved when the test material is totally utilized by microorganisms resulting in the production of CO2, (and possibly methane in the case of anaerobic biodegradation), water, inorganic compounds, and new microbial cellular constituents (biomass and secretions).
3.1.17 ultimate biodegradation test, n - a test which estimates the extent to which the carbon in a product has been converted to CO2 or methane, either directly by measuring the production of CO2 or methane, or indirectly by measuring the consumption of O2.
3.1.17.1 Discussion - The measurement of new biomass is not attempted.
