Oxo-degradable suggests degradation in the presence of oxygen. Polyolefins (PP, PE …) will fragment in the presence of oxygen and sunlight (UV) when the stabilizers added to the material to prevent such abiotic degradation have lost their efficacy. Some additives such as heavy metals and other materials, will accelerate this fragmentation. However, such fragmentation has repeatedly been shown to be purely due to breakage of
the polymer chains. There has been no reputable evidence that microorganisms are involved in any of this (biotic) degradation either in a aerobic compost or a anaerobic managed landfill environment.
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