Scaling up resource recovery of plastics in the emergent circular economy to prevent plastic pollution: Assessment of risks to health and safety in the Global South

Abstract

Over the coming decades, a large additional mass of plastic waste will become available for recycling, as efforts increase to reduce plastic pollution and facilitate a circular economy. New infrastructure will need to be developed, yet the processes and systems chosen should not result in adverse effects on human health and the environment. Here, we present a rapid review and critical semi-quantitative assessment of the potential risks posed by eight approaches to recovering value during the resource recovery phase from post-consumer plastic packaging waste collected and separated with the purported intention of recycling. The focus is on the Global South, where there are more chances that high risk processes could be run below standards of safe operation. Results indicate that under non-idealised operational conditions, mechanical reprocessing is the least impactful on the environment and therefore most appropriate for implementation in developing countries. Processes known as ‘chemical recycling’ are hard to assess due to lack of real-world process data. Given their lack of maturity and potential for risk to human health and the environment (handling of potentially hazardous substances under pressure and heat), it is unlikely they will make a useful addition to the circular economy in the Global South in the near future. Inevitably, increasing circular economy activity will require expansion towards targeting flexible, multi-material and multilayer products, for which mechanical recycling has well-established limitations. Our comparative risk overview indicates major barriers to changing resource recovery mode from the already dominant mechanical recycling mode towards other nascent or energetic recovery approaches.

Human health effects of recycling and reusing food sector consumer plastics: A systematic review and meta-analysis of life cycle assessments

“…For example, stochastic modelling has estimated that mechanical recycling could be scaled up by 2040 to process a maximum of only 33% of global total plastic municipal solid waste, limited by the projected capacity for waste collection, the economics of recycling and material losses (PEW Charitable Trusts and SYSTEMIQ, 2020), so limiting potential health benefits estimated in the meta-analysis. All LCAs included in this review modelled recycling as if it took place in an industrial, high-income setting, which does not account for factors such as the greater health risks experienced in the informal recycling sector in LMICs (Cook et al, 2022), nor international trade directing waste from high-income countries to LMICs (Brooks et al, 2018).…”

“…The respiratory effects of open burning were not considered, despite projections that 144 million metric tonnes of plastic will be burned annually by 2040 (PEW Charitable Trusts and SYSTEMIQ, 2020). Similarly, occupational hazards of the informal recycling sector including waste pickers, and the health effects of environmental plastic pollution were not modelled (Cook et al, 2022). As more data becomes available, it will be critical to develop methods of accounting for such health pathways in LCA, to improve estimates and evaluations of regionally representative and global health effects.…”

Fire and Oil Led to Complex Mixtures of PAHs on Burnt and Unburnt Plastic during the M/V X-Press Pearl Disaster

“…Conventional solid municipal waste methods may be options for fractions of the spilled plastic deemed non-hazardous waste. Recycling or upcycling reclaimed nurdles and other oceanic plastic has been suggested as a useful alternative to landfill disposal . However, separating nonhazardous material from hazardous material may prove too difficult to justify as this requires multiple disposal options.…”

“…92 However, in light of the amount of PAHs associated with the spilled plastic, other possible contaminants not measured in this study, and the thermal degradation of the plastic, this option may pose challenges to meeting feedstock quality and could pose health risks in products made from the recycled material. 94 The difficulty of separating the white nurdles from the unusable burnt plastic in an efficient manner may also stymie this option. 8 Despite the good intentions to reuse the material, recycling should be considered with caution as a disposal solution.…”

Integrating a Chemicals Perspective into the Global Plastic Treaty

“…High-temperature processes, e.g., gasification and using pyrolysis oil as a steam cracker feedstock, face similar challenges as stated above for waste-to-energy (Section S3.1). ,− The presence of certain chemical additives can result in unintended side reactions during chemical recycling and, thus, lower the overall efficiency and increase the generation of process waste that would require safe handling measures (Sections S2.2 and S3.1). Thus, similar to mechanical recycling, chemicals in plastics may lead to incompatibility of different waste streams, even of the same polymer type, as feedstocks for chemical recycling.…”