“Additives” are substances that are added to plastics to bring about certain changes to the characteristics of the plastics as desired and are usually included in the polymer matrix by blending in the melt phase but are not necessarily chemically bonded. This leads to the potential for them to be released into the environment during their production, use and waste phase. (Source: Technical guidelines of Basel Convention for the identification and ESM of plastic wastes and for their disposal (draft updated version of 23 February 2023) UNEP/CHW/PW-SIWG.4/3 1). Chemical compounds added during plastic compounding (the process of mixing or blending polymers and additives in a molten state) to fulfil specific desired functional properties in the production process or in the final plastic product, in which they can be divided into four different categories, namely functional additives, colourants, fillers and reinforcements. For example, plasticizers, flame retardants, thermal and ultraviolet (UV) light stabilizers, antioxidants, antimicrobial agents, biocides, pigments, antistatic and blowing agents, impact modifiers, lubricants, etc. (Source: Definition proposed in UNEP/PP/INC.3/INF/1 developed and modified from Chemicals in plastics: a technical report (UNEP and BRS Secretariat 2023) and From Pollution to Solution: A global assessment of marine litter and plastic pollution (UNEP 2021)).