Enhanced ready tests

OECD 301 B and F, Regulation (EC) Nr. 440/2008, C.4-C and C.4-D




Enhanced screening tests serve as a link between the screening tests of the OECD 301 series and elaborate simulation studies with 14C-labeled substances, in accordance with the ECHA strategy for persistence assessment. Since the enhanced tests build on the tests for determining ready biodegradability, they are referred to as "Enhanced Ready Biodegradability Tests"(eRBT). According to ECHA guidance, the currently accepted enhancements ("enhancements") are an extension of the test duration up to 60 days and the use of larger test vessels. Enhanced screening tests are used to assess whether a test substance can be classified as "non-persistent" in the environment. Only test methods that detect mineralization by CO2 evolution (OECD 301 B or OECD 310) or by oxygen consumption (OECD 301 F) are used. In the assessment of microplastics according to "ANNEX XV Restriction Report on Intentionally Added Microplastics", eRBTs represent one of 4 test categories.


The evaluation criteria have not yet been finalized. In a research project for the Federal Environment Agency, proposals were developed by Hydrotox GmbH. A degree of degradation of ≥ 60% of ThOD or ThCO2 within 60 days is considered evidence that the test item is not persistent. However, the reverse conclusion, according to which a degradation of < 60% THOD or rahter ThCO2 is an indication of persistence, is admissible. Proposals to derive “inherent degradability” from eRBT results have not yet been agreed either.

Further information

Gartiser S., Brunswik-Titze, A., Flach, F., Junker, T. Further development of screening tests for the evaluation of potential PBT substances. Final Report FKZ 3718 65 410 0, UBA-Texte series 10/2023, January 2023