Conventional petroleum-based plastics, such as polyethylene or polypropylene containing additives (metal salts) that act as a catalyst, or pro-oxidant, to accelerate fragmentation or mechanical or physical degradation when exposed to ultraviolet radiation or heat. Source: UNEP/World Resources Institute (2021). TACKLING PLASTIC POLLUTION: Legislative Guide for the Regulation of Single-Use Plastic Products. p.32 Sources: Green Dot Bioplastics