Which Biodegradability Test Is Best for Lubricants?

Which Biodegradability Test Is Best for Lubricants?

Oct 12th 2023

The US Environmental Protection Agency (EPA) has placed stricter regulations on lubricants to mitigate the effects of dangerous oil spills. These regulations are relevant for lubricants with the risk of coming into contact with the environment, such as water and soil. Companies in environmentally sensitive industries—agriculture, mining, forestry, and off-shore drilling—must use lubricants with specified levels of biodegradability.

Not all lubricant formulations are equal or identical, and it is up to the client to ensure the lubricant they use is up to industry standards. This leaves many industry professionals wondering which biodegradability test is best for lubricants and what can give them the best results.

OECD 301 B

This test measures how quickly a material experiences biodegradation in an environment within a certain time span. All biodegradability tests function differently, as one test cannot recreate or measure all conditions. OECD 301 B measures how quickly a material breaks down underwater in aerobic conditions. However, this test only measures the evolution of carbon dioxide and does not provide insight into the origin of the material. Additionally, it cannot indicate how quickly aromatic hydrocarbons degrade. Some believe that this test is not suited for complex mixtures such as industrial lubricants.


CEC L 103 12 uses gas chromatography to analyze the concentration of organic substances throughout a 21-day incubation period. Comparing OECD 301 B and CEC L 103 12 would be like comparing apples to oranges—they’re entirely different tests that measure different things. However, CEC L 103 12 rises to the challenge when measuring complex substances. It is not respirometric, which may pose a challenge for industry professionals looking to measure carbon dioxide evolution.

DIN EN ISO 9408 

DIN EN ISO 9408 measures the amount of oxygen consumption by evaluating the aerobic degradability of a material in a similar fashion to that of OECD 301 B. It calculates the ratio of oxygen consumption to the theoretical oxygen demand (ThOD), a solid degradation percentage. This test shines in its ability to test poorly soluble, insoluble, absorbing, or volatile samples. Additionally, where DIN EN ISO 9408 muses a manometric respirometry test, OECD 301 strictly measures CO2 evolution.

Now, we can look back to the ultimate question of which biodegradability test is best for lubricants. Unfortunately, the answer isn’t so clear-cut. The test you choose depends on the nature of the sample, what standards you must abide by, and what environmentally-sensitive industry the sample exists in. At Santie Oil, we can offer you biodegradable gear oils all in one place from reliable brands.