Kristine Hunsbedt Ersdala, Amaia Igartua,b, Susana Villa Gonzalez a, Andy M. Booth,b, Bjørn Henrik
Hansen,b,
and Lisbet Sørensen,a
a Norwegian University of Science and Technology (NTNU), Department of Chemistry, Trondheim, Norway
b SINTEF Ocean, Department of Climate and Environment, Trondheim, Norway
Email: krisers@stud.ntnu.no
Plastic resin pellets (commonly referred to as nurdles) are estimated to be the world’s second largest source of primary microplastics [1]. They contribute significantly to marine plastic pollution through spills during maritime transport, a problem that is expected to rise in the future due to increased plastic production [2]. Even before being used to make consumer products, pellets may contain intentionally added chemicals (e.g. UV-stabilisers and plasticisers), as well as non-intentionally added substances (NIAS). In addition to physical effects, microplastics may have negative impacts through leaching of toxic chemicals and degradation products into the environment [3]. The nurdles and associated leachates may be impacted by processes such as UV-degradation, potentially making them more toxic than non-degraded plastics [4]. Nurdles composed of low-density polymers such as polyethylene (PE) and polypropylene (PP) stay buoyant in surface waters [1], meaning that UV-degradation is of particular interest to study.
As part of the “Nurdletrack” project, PE and PP nurdles containing different additives were subject to accelerated UV-degradation in seawater. Leachates of UV-exposed nurdles were acutely toxic to marine organisms (S. costatum and L. littorea), while leachates from dark control samples were not. Here, we present a multi-platform non-target approach to investigate the chemical contents of the UV-exposed and non-UV-exposed seawater leachates derived from pellets.
Seawater leachates were extracted and analysed 1) using supercritical fluid chromatography coupled to high resolution mass spectrometry (SFC-HRMS) with electrospray ionization (ESI) in both positive and negative mode [5], and 2) using two-dimensional gas chromatography with HRMS (GC×GC-HRMS). Pre-processing was performed using a combination of commercial software, followed by suspect screening using mass spectral databases. Statistical tools such as PCA are used to explore the most significant differences between UV-exposed and dark control leachate samples. Differences in the elemental compositions of assigned molecular formulas will also be investigated, to further look into possible oxidation products caused by UV-exposure. The overall goal is to tentatively identify degradation products, plastic additives, and other chemical features in the samples that could explain the observed differences in toxicity.
References
1. Galgani F, Rangel-Buitrago N. White tides: The plastic nurdles problem. Journal of Hazardous Materials. 2024;470:134250.
2. Cocozza P, Scarrica VM, Rizzo A, Serranti S, Staiano A, Bonifazi G, et al. Microplastic pollution from pellet spillage: Analysis of the Toconao ship accident along the Spanish and Portuguese coasts. Marine Pollution Bulletin. 2025;211:117430.
3. Booth AM, Sørensen L. Microplastic Fate and Impacts in the Environment. In: Rocha-Santos T, Costa M, Mouneyrac C, editors. Handbook of Microplastics in the Environment. Cham: Springer International Publishing; 2020. p. 1-24.
4. Hernandez LM, Howarth-Forster L, Sørensen L, Booth AM, Vidal A, Tufenkji N, et al. UV-degradation is a key driver of the fate and impacts of marine plastics. How can laboratory experiments be designed to effectively inform risk assessment? Marine Pollution Bulletin. 2025;219:118271.
5. Tisler S, Savvidou P, Jørgensen MB, Castro M, Christensen JH. Supercritical Fluid Chromatography Coupled to High-Resolution Mass Spectrometry Reveals Persistent Mobile Organic Compounds with Unknown Toxicity in Wastewater Effluents. Environmental Science & Technology. 2023;57(25):9287-97.