Informal recycling sector contribution to plastic pollution mitigation: A systematic scoping review and quantitative analysis of prevalence and productivity

Abstract Ongoing negotiations for a ‘Legally Binding Instrument on Plastic Pollution’ recognise the substantial contribution made by the informal recycling sector (IRS - waste pickers) to plastic pollution mitigation as part of just transition. Negotiating parties will require baseline evidence of the sector’s activities to inform the development of local and national actions plans. To this, we carried out a review of IRS prevalence and productivity following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) method followed by extensive (statistical) data analytics. Waste pickers represent median 0.2% (interquartile range – IQR: 0.1-0.5%) of the urban population worldwide, collecting between 20 kg and 80 kg of engineered materials for recycling each day, of which 30% (mean wt. ar) are plastics. We identify substantial shortcomings in most methodologies used to gather data on the IRS, introducing epistemic uncertainty into some previous estimates of the sector’s activity. We recommend development of a standardised resource-efficient method of sampling and data gathering, suitable for implementation at municipal/local scale. Our work offers verifiable quantitative knowledge on the sector’s activities to date, suitable for use in plastic pollution quantification models and local/national action plans required to baseline and monitor progress towards multilateral targets.