| Summary: | The last few decades have witnessed an exponential increase in plastic production and consumption. The inexorable increase in microplastic accumulation, particularly in the Arctic waters, has become a major environmental concern. Discarded plastics degrade in the environment due to natural forces like wind, waves, and heat into smaller pieces. Plastic fragments produced or decomposed into a size range of 1 μm to 5 mm diameter are termed microplastics. Plastic debris travels through various environmental media before eventually reaching the oceans. In the various oceans, they travel along oceanic currents reaching the Arctic, where they get trapped in the Arctic ice. Moreover, local maritime operations like fishing, tourism, shipping, hydrocarbon exploration, and aquaculture also contribute to the microplastic accumulation in the Arctic waters. Microplastics are a complex group of pollutants containing plastic polymer, various stabilizing chemicals intentionally added during their production process and numerous other chemicals sorbed while being in the environment owing to their high surface area. These chemicals collectively enhance the toxicity of microplastics. The omnipresent microplastics possess characteristics such as toxicity, long-range mobility, bioaccumulative nature, and environmental persistence. The interaction of such an intricate pollutant like microplastic in the intriguing Arctic environment characterized by a ubiquitous sea-ice presence, extreme light regime, and unique species dwelling in makes them a serious threat to the Arctic marine ecosystem and the biota inhabiting it. Despite the pressing nature of this concern, there is a paucity of literature on microplastics and a dearth of research on investigating the associated risk. The work presented here assesses the risk posed by microplastics in the pristine and sensitive Arctic region. This thesis comprises two main contributions. Firstly, it develops an ecotoxicological risk model in polar cod (Boreogadus saida), a pivotal species of the ...
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