This document specifies a method to determine the specific aerobic biodegradation rate of solid, non-water soluble plastic materials under mesophilic conditions.NOTE The specific aerobic biodegradation rate (which, strictly speaking, is a specific mineralization rate, implying the assessment of the conversion of organic carbon into CO2 but neglecting biomass formation) is expressed as amount of carbon mineralized into CO2, per unit time, per unit area.The method described in this document does not provide information on the ultimate aerobic biodegradability of the tested samples. Biodegradability criteria for plastic materials under mesophilic conditions are provided for example by ISO 23517, and ISO 22403. The method described in this document shall be used to determine the DT50 only when the plastic material is proven to be intrinsically biodegradable using suitable standard specifications such as ISO 23517 and ISO 22403. Furthermore, the biodegradation rate determined on plastic materials whose ultimate biodegradation has not been proven, shall not be considered as a specific characteristic of the whole material.This document only considers the evolution of CO2 as direct measurement of mineralization of the tested sample.The method described in this document may be applied also to solid materials used as a reference.This document is not applicable for “marine, soil and freshwater biodegradable” claims of biodegradable plastic materials. For such purposes, see relevant product standards if available.NOTE Although results can indicate that the tested plastic materials and polymers will biodegrade under the specified test conditions at a certain specific aerobic biodegradation rate or DT50, the results of any laboratory exposure are not directly applicable to environmental compartments including soil, marine environments and limnic areas at the actual site of use or leakage.