Today, microplastics are emerging as an important environmental problem with health, economic and social impacts. Plastic fragments or plastic fibers whose size is less than five millimeters (sizes 5mm-1µm) are characterized as microplastics. Although very small in size, plastic waste in all shapes and sizes is one of the most serious threats to marine ecosystems around the world. According to the European Association of Plastics Raw Materials (PlasticsEurope) and UNEP the global production of plastic today has soared to 400 million tons per year. An estimated 1,000 rivers are responsible for almost 80% of the world's annual riverine plastics ending up in the ocean, ranging between 0.8 and 2.7 million tonnes per year, with small urban rivers being among the most polluting.

The main source of microplastics is plastic waste that ends up in the sea through urban sewage pipes, which are broken down through chemical and physical processes into smaller pieces and particles or fibers. Another source of microplastics is synthetic clothing, from which approximately 1,900 microplastic fibers are released in each wash into the sewage system and, by extension, into the marine ecosystem. In addition to these two sources, microplastic is also channeled directly into the environment in an even more dangerous form, the form of plastic microbeads, i.e. tiny particles of hard plastic used in personal care products that are almost always smaller than 1 millimeter. These are plastic industrial products (e.g. cosmetics, shampoos, deodorants), which consist of various forms of plastic such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polymethyl (PMMA) and nylon. After the use of these products, the microbeads pass directly through sewage networks, as they are too small to be retained by the filters usually used in wastewater treatment plants, and end up in rivers and streams, with a final destination in the seas and oceans , where they are kept for decades.

Each of us releases an average of 2.4 mg of microplastics into the environment every day, which eventually ends up in the sea, whether the sewage is treated or not, because although a large volume of it ends up in sewage treatment plants, its collection is not possible with today's technology. Many such microplastics have been found in all marine organisms, including important fisheries (fish, crabs, mussels, etc.). Their consumption by marine organisms results in them dying at a faster rate than they reproduce, slowing down their movement and dulling their senses, making them more vulnerable to their natural predators. In particular, the ingestion of microplastics slows growth and alters the process of secreting chemicals that warn fish of the presence of predators, making them easier prey for them.

Microplastics not only enter the fish food chain, but also affect their behavior and increase their mortality even more. Consequently, the consumption of fish by humans has an impact on human health. Microplastics have been found in food and drinks, such as beer, honey and drinking water. Let us recall at this point that microplastics have been blamed for various effects on human health, such as their role as "hormone disruptors". Microplastics are then transformed into nanoplastics continuing to affect human health. A US study recently found that bottled water contains "hundreds of thousands of invisible nanoplastics" that can pass through the intestines and lungs directly into the bloodstream. They can then end up in organs such as the heart and brain, or through the placenta and even in the bodies of fetuses. It is now widely accepted that microplastics pose a real threat to humans and natural ecosystems because they remain in water and pollute our seas and oceans for thousands of years. Their numbers in marine ecosystems have increased rapidly.

In our country, the "Nireas" International Water Research Center of the University of Cyprus studies the presence and behaviour of microplastics in municipal wastewater treatment plants. Also, the AKTI Center for Studies and Research revealed the detection of microplastics on our coasts, with up to 4000 microplastics per square meter of coast, which were detected both on the touristic coasts of Cyprus and on remote coasts. Also, the Cyprus Center for Environmental Research and Education (CYCERE) constantly highlights the issue through its actions in the context of Environmental Research, Environmental Education and Environmental Awareness. Also important is the "Plastic-free Beaches" initiative promoted by the Cyprus Sustainable Tourism Organization, which comes to strengthen efforts to address this important problem.

Already in 2018, the European strategy for limiting plastic waste includes measures such as:

• Directive on single-use plastic products and fishing gear

• Measures to limit the use of microplastics in products and address and reduce the unintentional release of microplastics into the environment

• Measures for biological, biodegradable and compostable plastics

• New rules for port reception facilities to deal with marine litter.

Concerns about the presence and impact of plastics in the environment led to the decision to conclude an international agreement (Resolution 14) of UNEA-5, to reduce and/or eliminate plastic pollution by this year 2024, by representatives of 175 nations that took part at the fifth session of the United Nations environment assembly in Nairobi, Kenya, which took place in 2022. Also, the "circular economy" is one of the best and most economical ways to reduce plastic waste. Also, the ban on single-use plastics has been a very important EU policy to tackle the problem of plastic waste and microplastics.

It is imperative, therefore, to deal with this pollution at its sources and to limit the production of microplastics and plastic waste in general. Businesses and industries related to the production and use of microplastics and plastic waste should adopt new policies of using alternative materials by replacing plastic materials as soon as possible. However, we recommend that specific policies and strategies be adopted at both national and European level, and existing ones be strengthened, to address this important environmental challenge of microplastics and plastic pollution.

A "National Strategy to deal with plastic pollution and microplastics" as we propose will be able to include measures at individual and collective level, at local and national scale for various productive and social groups, for industries, organizations and businesses, for local authorities, municipalities and communities. The measures to be included should be properly targeted to achieve optimal results with multiplier benefits. Such a strategy could be included in Cyprus' initiatives and proposals for the environment sector in the context of the Cyprus Presidency of the Council of the European Union in 2026.