A test method to assess the ‘inherent’ biodegradability of oil products

Report no. 99/59: This report describes the development of a test method for assessing the potential of oil products to be biodegraded in the environment (‘inherent’ biodegradability). The method produced was based on International Standard ISO 14593 (‘CO2Headspace Test’) but used a pre-exposed inoculum and an extended test duration.

The work of the CONCAWE Biodegradation Task Force is summarised and details are given of an international ring test which demonstrated the practicality of the new method and determined its precision. As a preliminary to submission of the method to the Organisation for Economic Co-operation and Development (OECD) for consideration as a new test guideline for assessing ‘inherent’ biodegradability, the method has been prepared in ‘OECD format’ (included as an appendix to this report).

During the course of the Task Force’s work, CONCAWE funded a one year project with the University of Hull to evaluate techniques for measuring the incorporation of test substance carbon into new microbial biomass during biodegradation under the conditions of the CONCAWE test method. The report also describes this research and summarises its main findings.