A note on the use of the CEC L-33-A-93 test to predict the potential biodegradation of mineral oil based lubricants in soil

The biodegradabilities of five unformulated mineral oils (brightstock, 150 SN base oil, white oil and two gas oils) were determined in the CEC L-33-A-93 test and during 20 weeks incubation in nutrient-supplemented soil microcosms. Biodegradation in both studies was measured as the loss of extractable hydrocarbon (‘primary’ biodegradation). There was a statistically significant (P <0.01) rectilinear relationship between the extents of biodegradation in both test systems. The results indicate that the CEC method could be used as a relatively simple, quick and inexpensive test for assessing the potential biodegradation of mineral oil based lubricants in soil.