Thermal deconstruction, open burning and disposal of e-waste without pollution control: A systematic review of risks to occupational and public health

Abstract

The critical functionality provided by the informal e-waste recycling sector to the global circular economy is marred by the hazardous emissions from this practice when it is carried out under informal and unregulated conditions in the Global South. Here, we focus a systematic review (PRISMA) of evidence specifically on rudimentary thermal processing activities that are carried out to disassemble and recover metals bonded into the complex assemblies and composites of electrical and electronic products and items. We identified main combinations of hazard-pathway-receptor (H-P-R) associated with exposure to risk and ranked them to indicate severity and prioritise research needs and interventions. Two practices, open burning and heating/melting/roasting are highly efficient in comparison to mechanical disassembly of many components and materials, presenting a challenge for actors who want to discourage them. Yet, these activities result in significant and very serious potential health effects as evidenced by 48 references screened and critically assessed. Though a large body of research exists that report observations of potentially hazardous substances in environmental media and human bodies, there is an abject paucity of reliable or even indicative data to indicate the scale of the e-waste processing activity. Moreover, the concentrations measured in almost all studies suffer from a multiplicity of confounding activities, creating challenges regarding identifying the activity source. System level interventions should be designed to effectively mitigate the risk, whilst rapidly transitioning to low-risk processing with effective pollution abatement in place and safe systems of work.