Plastic waste poses a significant environmental challenge, drawing considerable research, media, and policy attention primarily focused on its visible impact. The plastic industry incorporates various additives, such as plasticisers, to achieve desired product properties. Consequently, plastics are potential vectors for the release of these additives into the aquatic environment, posing ecotoxicological risks. Despite the prevalence of these additives in aquatic ecosystems, there are substantial knowledge gaps concerning their ecotoxicological effects, especially in the context of Life Cycle Impact Assessment (LCIA). There is a lack of characterization models for additives to assess their environmental impact on the plastic life cycle. This study aims to address this gap by providing aquatic ecotoxicity data aiming to calculate EF specifically for plastic packaging additives. We conducted a battery of ecotoxicological tests involving species from three trophic levels, to estimate effects such as growth inhibition of algae Raphidocelis subcapitata, acute immobilisation of invertebrate Daphnia magna, as well as the toxicity assessment of the luminescent bacteria Aliivibrio fischeri following OECD guidelines and the requirements to produce relevant data for LCIA advances. These data are crucial for a better understanding of the environmental impact of plastic additives on aquatic ecosystems, contributing to LCIA by refining and expanding the available sets of effect factors. Advancements in this area enhance plastic life cycle assessment, enabling the identification of toxicity associated with additives and the estimation of their chemical footprint. The findings of this study not only expand the number of effect factors available for additives used in plastic packaging but also support initiatives aiming to minimize environmental hazards associated with plastic waste. This knowledge should also inform sustainable practices in plastic production.