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STIPINST-Stipendiatstillinger i instituttsektoren

Stipendiatstilling 1 NIVA (2020-2023)

Awarded: NOK 4.1 mill.

The global production of plastics is vast, leading to a steady increase in plastic waste. Due to inefficient waste handling and recycling, large amounts of plastic debris enter the environment every year. Since plastics degradation is a slow process, it ends up accumulating in the environment. Plastic waste breaks down into micro- and nano-sized particles, which are known to be ingested by organisms with unknown consequences. Any plastic hazard does not only result from the plastic itself, but more importantly from the chemical additives that are incorporated during production and processing steps. These chemicals might be carcinogenic, mutagenic and reprotoxic, be persistent and bioaccumulate through the aquatic food web. In this context, this PhD project aims to investigate the long-term effects of micro(nano)plastics and their chemical additives in the model organism blue mussel (Mytilus edulis). Blue mussels are important in the ecosystem, as a food source and are often used as model organisms. The first part of this PhD is focused on developing cell-based methods to study interactions with cellular membranes, uptake mechanisms, cellular localization and toxicity of small plastic particles. In a first approach, flow cytometry methods were developed to study the basal functional, physiological, and immunological responses of blue mussel’s haemocyte cells. Subsequently, mussels were exposed to PMMA (poly(methyl methacrylate)) nanoplastics and their ecotoxicological impact was investigated using the developed tools. After 24 hours exposure, results revealed impairment of haemocytes health status, with cell viability and cytoplasmatic membrane potential being the most impacted. The integrated effects assessment using flow cytometry proved to be a fast, accurate and reproducible cost-effective alternative tool to quickly predict toxic effects at conditions close to an in vivo state in mussels. The second part of this PhD evaluates the potential effects of micro(nano)plastics derived from commonly used consumer products and their chemical additives, also with mussels as a model species. To achieve this, mussel sensitive life stages, i.e., embryos, as well as haemocytes, will be exposed to plastic leachates from different consumer products, chosen according to their chemical profile. Haemocytes were exposed to leachates derived from car tire granulates (CTR), balloons (BL), shoes soles (SS), dishwashing gloves (DG) and PET bottles at sub-lethal concentrations. According to the toxicity screening, PET bottles had lower toxicity potential and were used as a negative control. Overall, haemocytes were significantly affected by all leachates, with SS and CTR leachates showing the higher toxicity. Surprisingly, PET bottles leachates also had negative effects in haemocytes. Metabolic activity, lysosome presence, mitochondrial membrane potential and ROS activity were the most affected parameters for all leachates. This study demonstrated that leachates from plastic consumer products compromise haemocyte functionality at low concentrations. Moreover, it will contribute to understanding the toxicity mechanisms of plastic chemical additives towards marine organisms. Furthermore, mussels will be exposed to these consumer products and their isolated leachates to assess bioaccumulation and biological effects to understand if the chemical additives and/or the plastic polymers cause toxicity. Finally, trophic transfer experiments will be performed to assess their ecological impact on key species and ecosystems. Overall, the research framework envisioned for this PhD project will increase the quality of data and scientific knowledge on the interaction between micro(nano)plastics, chemical additives, cells and organisms and thus provide a scientific baseline for future risk assessment of plastic particles and associated chemicals.

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STIPINST-Stipendiatstillinger i instituttsektoren

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