UNSEEN: Are unseen plastic particles in the global ocean already beyond the "no-effect" concentrations?

Lead Research Organisation: University of Surrey
Department Name: Chemistry

Abstract

Studies investigating effects of nanoplastics (NPs) on aquatic organisms used concentrations between 2 to 7 order-of-magnitudes higher than those predicted in ocean to track NPs. These studies divided the community between those sounding the alarm due to the observed ecotoxicological effects, and those predicting that NP concentrations in the environment are far below any threshold-effect. In reality, most experiments were inadequately designed. Fit-to-purpose experimental designs have been hindered by a lack of appropriate NP models, tracking methods, and monitoring strategies for environmentally realistic concentrations. Using 14C-labelled NPs and conventional nuclear techniques, we recently modelled that scallop, chronically exposed to environmentally realistic NP concentrations (15 ug/L) might accumulate and reach NPs body burden where effects are observed by those sounding the alarm. Astonishingly, this suggests that NPs are already beyond threshold-effects in organisms and harming the marine biota.

UNSEEN will investigate whether NPs in the oceans are already beyond "threshold-effect" concentrations?

Using a successful radiolabelling approach, UNSEEN will establish a new methodology for correlative imaging of NPs with elemental and molecular imaging using ion beam analysis (IBA) and mass spectrometry imaging (MSI). This analytical approach will provide a unique insight into the potential effects of NPs.

The overall goal of UNSEEN is to go beyond a mere qualitative evaluation of the distribution of NPs in the food web, and to generate quantitative, spatially-resolved toxicokinetic and metabolomic data. Quantitative tissue distributions of NPs, following realistic chronic NP exposures, will be directly compared to the spatially-resolved metabolomic data. This will provide a proof-of-concept for a truly novel approach.

UNSEEN addresses key questions of whether NPs accumulate in the food-web and whether NPs are harming aquatic organisms at environmentally realistic concentrations after long-term exposures. The approach proposed here is essential and will produce unique, valuable and fundamental knowledge on the combined long-term consequences of NPs and their additives in aquatic environments. This is critical for developing appropriate management strategies regarding plastic litter. If successful, UNSEEN will indeed support policy makers in improving environmental risk assessments of NPs. It is envisioned that the approach proposed herein will enable a step-change in the research on contaminants of emerging concerns and will allow the study of many different aspects of their fates (e.g., transformation, fragmentation, biomineralization, biodistribution). The unconventional approach will fully integrate the processes that govern the biological responses to NPs and provide an understanding of the potential effects of NPs that could be translated to human health.
UNSEEN chooses a highly innovative approach to address its research questions. It combines radiochemistry and very emergent technologies from biomedical sciences using ion beam analysis (IBA) and mass spectrometry imaging (MSI) to resolve important environmental questions. It will establish 14C-labelled NPs as a gold standard for performing realistic laboratory-based studies. It is fundamental research that will have a critical impact beyond its overall goal. The research proposed will, for instance, have a huge impact on the use of 14C as low-level tracer in biomedical studies (i.e. micro-dosing), where appropriate methods are often missing. The approach proposed is unique and will allow to perform ground-breaking science that goes beyond the state-of-the-art. UNSEEN builds a unique inter-disciplinary research team that integrates the relevant expertise in environmental analytical chemistry, radiochemistry and ion beam physics.

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