Additive chemicals in plastic consumer products and their role in plastic toxicity

, Booth Andy, Igartua Amaia, Lyngstad Inger, Wagner Martin, Gomes Tânia, Almeida Ana Catarina, Øverjordet Ida Beate, Sørensen Lisbet.

Toxicity assessment of most plastic and microplastic (MP) materials is typically conducted using pristine reference materials that do not accurately reflect the partially degraded materials normally found in the environment. Importantly, few studies have considered the role of plastic additive chemicals as the possible source of any observed toxic effects from MP exposure. All plastic consumer products contain chemical additives that provide the material with specific properties, including softeners, dyes, antioxidants, UV stabilizers, antimicrobials and flame retardants. Many also contain residual chemicals used in polymer and/or product production processes. In the current study, 50 plastic consumer products representing different polymer types with a broad range of additive chemical profiles were characterised and their baseline toxicity towards aquatic species investigated using a tiered approach. All test materials were commercially sourced and cut into small pieces prior to use. First, solvent extracts of the plastic products were subjected to non-target screening using chromatography coupled to mass spectrometry, with compounds tentatively identified based on matches to mass spectral libraries. To allow investigation of a large sample set, data processing, including spectra deconvolution, library matching, logical filtering and searches against online PBT databases, has been automated to a large extent. A broad range of additive chemicals were identified in the different plastic products. As expected, the additive chemical profiles were found to vary significantly between the products, with some containing very little and others containing either a large number of different additives, specific additives at high concentrations, or a combination of the two. All test materials were then subjected to solvent extraction by methanol and transfer to DMSO prior to toxicity screening assessment by the marine Bacteria Luminescence Toxicity (BLT) test and marine microalgae (Skeletonema pseudocostatum).

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