Quantification of recycled content in plastics: a review

The increasing demand for plastic products has generated unprecedented amounts of plastic waste. To reduce both proper and improper plastics disposal and the concomitant long and short term physical and chemical risks, recycling has emerged as an effective and complementary tool to recover waste and lower demand for unsustainable virgin plastics production. Post-consumer and post-industrial recyclate is often mixed with virgin plastic to satisfy performance criteria. To drive demand, countries such as the UK, USA and Australia have recently mandated recycled plastic content targets. Incorporation of recyclate necessitates recycled content quantification tools to prevent misleading claims about the environmental sustainability of a product. However, methods to quantify recycled content are multi-faceted, with different approaches resulting in different measurements for any one product, creating dissonance and mistrust between governments and producers. This review discusses recycled plastic content and its current role in global legislation, the mass balance approach favoured by supply chains to assure origin or composition, as well as laboratory methods to quantify recycled plastic content, according to their feasibility and authenticity. Particular focus is given to plastics in the packaging sector given their prevalence in legislation and widespread use.