Test No. 301: Ready Biodegradability covers six methods that permit the screening of chemicals for ready biodegradability in an aerobic aqueous medium. In general, a solution or suspension of the test substance in a mineral medium is inoculated and incubated, normally for 28 days, under aerobic conditions in the dark or in diffuse light. Degradation is monitored by the determination of parameters such as dissolved organic carbon (DOC), CO2 production and oxygen uptake and compared with standard thresholds for biodegradability.