# E-Waste Plastics in the Environment: Assessment, Characterisation, and Bioprocessing
## 1 Introduction  
Waste electrical and electronic equipment (WEEE or e-waste) refers to waste materials from such equipment and components without the intent for further use or reuse [1]. As technological needs evolve and older electric and electronic equipment reaches obsolescence faster and faster, the growth of e-waste volumes has accelerated. Currently, this is the class of waste with the most accelerated growth, with projections pointing towards 82 billion kg of generated e-waste as early as 2030 [1]. Although e-waste presents an economicopportunity (annually valued at 91 billion US dollars (USD)), it is estimated that only 22.3% of such waste is formally recycled on an annual basis [1]. Instead, a large portion of e-waste is moved across geographical boundaries, usually towards the Global South. There, a combination of less robust regulatory frameworks, and the lack of enforcement and proper infrastructure for e-waste management have allowed for the cheap dumping of this waste, despite legislative efforts towards the regulation of e-waste management [2; 3]. In such countries, discarding and informal handling remain common, exposing local populations and environments to multiple hazardous components. The Basel Convention, implemented to oversee the transboundary movements of hazardous waste, on the other hand, has had limited success [1; 4; 5]. This is due to the mislabelling of waste, and the mixing of hazardous and recyclable wastes have been strategies used to circumvent the convention's terms [6]. Formal recycling methods still focus mainly on the recovery of metals, the more precious and strategic of the e-waste components, to the detriment of others, such as plastics, where the motivation of profit from recycling is less clear [7]. The plastic components of electrical and electronic equipment and e-waste (e-plastics and e-waste plastics) contain a variety of polymeric materials and additives, such as plasticisers and flame retardants, which present challenges for recycling. Conventional recycling methods require a high degree of purity to maintain the quality of the recycled end product [8], but e-waste plastics demand additional sorting and processing to remove additives and to ensure the quality of the recycled products. This increases the labour intensity and investment required by recycling industries, ultimately reducing the economic viability of the process [9; 10]. Given the high costs and diminishing returns of traditional approaches for e-waste plastic treatment, these can be comparatively disregarded during e-waste processing, focusing mainly on the metal components. Instead, they are frequently exported for disposal or uncontrolled recycling. According to [PERSON] et al. [9], it is estimated that, currently, approximately 2.6 million tonnes of e-waste plastics are generated annually in Europe, of which only 1.3 million tonnes are being officially collected, and 1 million tonnes enter official e-waste plastics recycling facilities. The remaining 300 kilotonnes end up processed at substandard recycling facilities, exported, or sent to incineration after e-waste pre-processing. Traditional approaches to treating e-waste plastics are often associated with high costs and limited economic returns, making them less favourable for e-waste processing. As a result, attention tends to focus on recovering metal constituents from e-waste (currently estimated to be approximately 60% of the total metals found in e-wastes [1]). Currently, the generation of e-waste plastic, often including unrecyclable polymeric blends, represents an economic, health, and environmental challenge [11]. Furthermore, although extensive studies have been conducted on conventional and virgin plastics (e.g., as reviewed by [PERSON] et al. [12]), the study of e-plastics and specifically e-waste-derived plastics has lagged, possibly due to their complex nature and lack of comparable results.