# Hyperspectral Imaging for Detecting Plastic Debris on Shoreline Sands to Support Recycling
## 1 Introduction  
Marine litter, defined as any persistent, human-made, or processed solid waste material discarded or left behind in marine or coastal environments, has become one of the most pressing environmental issues of our time [1, 2]. Plastics constitute at least 85% of all marine waste, making them the most prevalent, hazardous, and long-lasting component of marine litter [3]. Projections indicate that, by 2040, the amount of waste entering the ocean will almost triple, increasing by 23-37 million metric tons annually. According toa sustainability-focused company review of plastic waste, this amount is equivalent to approximately 50 kg of plastic per meter of coastline annually [4]. The impact of marine plastics extends across ecosystems, wildlife, and human health, leading to significant ecological and socio-economic consequences. Marine plastics reduce the quality of marine ecosystems and endanger wildlife through ingestion, entanglement, and exposure to toxic contaminants such as heavy metals (HMs) and persistent organic pollutants (POPs) [5; 6]. Ingested plastic can accumulate and spread through food chains to higher trophic levels, making humans similarly susceptible. Plastics are consumed through seafood, beverages, and even ordinary salt and can enter the body through the skin or be inhaled when present in the air [7]. This contamination can lead to abnormal reproductive processes, developmental issues, hormonal alterations, and even cancer. Plastics are particularly resilient, with degradation processes slowed considerably in aquatic environments compared to terrestrial ones. While photodegradation on land is relatively efficient due to direct sunlight exposure, plastics in water are shielded from ultraviolet (UV) radiation and subjected to lower temperatures, resulting in extended persistence and accumulation of marine debris [8; 9]. Marine plastic pollution not only poses severe environmental hazards but also has far-reaching economic and social consequences. significantly disrupting livelihoods. Plastic pollution disrupts communities reliant on fishing, tourism, and pristine coastal environments, leading to economic losses associated with reduced fish stocks, declining tourism due to polluted beaches, and compromised food safety [10; 11; 12]. Furthermore, plastic pollution raises healthcare costs due to pollution-linked diseases, exacerbating socio-economic inequalities and impacting the well-being of vulnerable communities [13]. Economically, the global economic impact of marine plastic pollution is estimated to range between USD 6-19 billion annually, affecting industries such as tourism, fisheries, and aquaculture, as well as incurring cleanup costs [14]. Plastic debris often reaches shorelines through ocean currents, where large items degrade into smaller particles, becoming \"secondary\" microplastics (MPs) [2]. Marine plastics are typically classified by size into mega-plastic (>100 mm), macro-plastic (100 to 20 mm), meso-plastic (20 to 5 mm), micro-plastic (<5 mm), and nano-plastic (<100 nm) categories [11; 12; 13]. When macro-plastics break down into very small particles [15], recovery and recycling become very challenging. Given the environmental persistence of plastics and the complexity of managing their impacts, a multifaceted approach involving various stakeholders is essential. Governments, industries, and individuals all have crucial roles in addressing plastic pollution through policies and regulations that encourage reduced plastic production, promote recycling, and advocate for sustainable alternatives [16].