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ASTM D5864 and ASTM D6731 are two standard biodegradation test methods for determining aerobic aquatic biodegradability of lubricants or their components.

ASTM D5864 and D6731 are two ASTM methods specifically designed for the biodegradation test of lubricants or their components. ASTM D5864 measures the CO2 evolution, which is equivalent to the OECD 301B method. ASTM D6731 measures the oxygen consumption, which is equivalent to the OECD 301F.

ASTM6731 is our preferred method for lubricant test due to its simple system setup and high applicability.

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ASTM D5864 test overview

ASTM D5864

Similar to the OECD 301B CO2 Evolution Test, ASTM D5864 measures the CO2 evolution to reflect the biodegradation of fully formulated lubricants or their components, based on the exposure to activated sludge from municipal wastewater treatment plant as the inoculum under laboratory conditions.

This method is designed for all lubricants that are not volatile and are not inhibitory to the inoculum at the test concentration. It is intended to specifically address the issues associated with insoluble substances and complex mixtures that are commonly found in lubricants.

It can handle materials that are soluble, insoluble and/or absorbing. Good dispersion with continuous mixing is usually required for better performance.

Test substances that achieve high levels of biodegradation are assumed to be easily biodegradable in most aerobic aquatic environments.

OECD 301B CO2 evolution ready biodegradability test laboratory setup

ASTM D6731 (highly recommended)

Similar to the OECD 301F Closed Respirometer Test, ASTM D6731 measures oxygen consumption to reflect the biodegradation of fully formulated lubricants or their components, based on the exposure to activated sludge from municipal wastewater treatment plant as the inoculum under laboratory conditions.

It has the highest applicability among all other methods and can handle materials that are highly soluble, poorly soluble, insoluble, volatile, involatile, and/or adsorbing. Good dispersion with continuous mixing is usually required for better performance.

Test substances that achieve high levels of biodegradation are assumed to be easily biodegradable in most aerobic aquatic environments.

ASTM D6731 is our second recommended method (following OECD 301F ) due to its simple experimental setup and high applicability.

Requirement and Applicability

Different testing methods are applicable for materials with different properties. Below is a summary of the applicability of ASTM D5864 and D6731. Please check our Method Selection Guide to select the most appropriate method for your materials. You can also find the applicability for many other methods on Aropha Resource Center
.

Test Analytical method Sample info required* Poorly soluble Volatile Adsorbing
ASTM D5864 (CO2 evolution test)
CO2 evolution Carbon content + - +
ASTM D6731 (Closed respirometer test)
Oxygen consumption ThOD or COD + +/- +

*"Sample info required" is the information needed to calculate the biodegradation percentages. This must be available for a selected method.
*"Carbon content" is the ratio of the carbon weight to the weight of the sample. It can be calculated by the sample formula (e.g., acetic acid C2H4O2, carbon content is 12*2/(12*2+1*4+16*2)=40%) or measured experimentally. At Aropha, we currently do not provide such an analysis service.
*"COD" analysis is available and free at Aropha.

Aropha Resource Center

To learn more about different types of biodegradation tests, their applicability, biodegradation mechanisms, and many other information such as case studies, publications, and blogs, please check our Aropha Resource Center
.

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