Ready Biodegradability (ISO 14593 / OECD 310)
Freshwater Ready Biodegradability – CO2 Headspace Test
This method is based on ISO 14593 / OECD 310 : ‘Carbon dioxide (CO2) Headspace Biodegradation Test’ and provides a test for assessing the ultimate, aerobic biodegradability of organic substances in the freshwater environment. It provides similar information to the methods described in OECD 301.
The test is performed in sealed bottles with a headspace of air that provides a reservoir of oxygen (O2) for aerobic biodegradation. CO2 evolution from the ultimate aerobic biodegradation of the test substance is determined by measuring the inorganic carbon (IC) produced in the test bottles over that produced in blanks that contain inoculated medium only. The ultimate aerobic biodegradation is the breakdown of an organic chemical by micro-organisms in the presence of O2 resulting in the production of CO2, water and mineral salts (ie mineralisation) and microbial cellular constituents (biomass).
The extent of biodegradation is then expressed as a percentage of the theoretical maximum IC production (ThIC), based on the quantity of test substance (as total organic carbon) added initially. The test is typically run for 28 days. Values =60% ThIC in a 10 day window demonstrates ready biodegradability.