On October 4, we had the opportunity to explore the Geopark of the Basque Coast through one of our Running Minds events, a setting of great geological and environmental value. During the visit, we learned about its history, biodiversity,and the importance of preserving such a unique space.
However, development and human activity have affected this environment in various ways, altering both its natural balance and the quality of its ecosystems. Izaskun Zurita, Gonzalo Torre, and María Calvo joined us to analyze one of the most relevant causes, which concerns both this place and all of us: the environmental impact of plastic.
The Basque Coast Geopark, recognized by UNESCO, covers the municipalities of Mutriku, Deba, and Zumaia, with an approximate area of 90 km². Its distinctive feature is the flysch: a formation of alternating rock layers of different hardness, formed on ancient seabeds. This geological formation allows the study of global phenomena, such as the Cretaceous extinction or climate warming events similar to the present.
In addition to its geological value, the Geopark includes four protected natural areas: the Deba-Zumaia coastline and the SCIs of Arno, Izarraitz, and Urola, which host a wide variety of coastal and mountain habitats. However, as in most coastlines worldwide, plastic pollution is also present. In areas such as Sakoneta Beach, small fragments accumulate among the algae, making their removal difficult without damaging the ecosystem. In response to this issue, the Geopark promotes awareness campaigns and waste collection activities with local volunteers, contributing to environmental improvement and citizen awareness.
–Gonzalo Torre
The origin and presence of microplastics in the ocean
According to researchers at AZTI (Institute of Marine and Food Science and Technology), around 80% of marine litter comes from land-based activities, such as poorly managed landfills, wastewater, or tourism, while the remaining 20% originates from fishing, maritime transport, and aquaculture. Once in the sea, plastic waste fragments due to solar radiation, waves, and friction with other materials, producing microplastics (particles smaller than 5 mm).
These can be classified as primary, manufactured at that size (such as microbeads in cosmetics or industrial pellets), and secondary, derived from the fragmentation of larger objects. Due to their small size, most escape treatment systemsand end up in rivers and oceans. Their widespread presence and persistence in the environment make them one of the most pervasive and difficult-to-eliminate pollutants.
–Izaskun Zurita
The main environmental problem of plastic is its non-biodegradability. Complete degradation can take decades or even centuries, which increases its cumulative impact. The effects vary depending on the size of the plastics and the organisms affected:
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Entanglement and snaring: fishing nets, bags, or plastic rings trap fish, turtles, and marine mammals, causing asphyxiation, injuries, or mobility difficulties.
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Ingestion: many species mistake plastics for food. Birds and cetaceans may ingest them thinking they are prey, which blocks their digestive system and causes malnutrition or death.
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Asphyxiation and habitat loss: the accumulation of debris on corals or seagrass beds reduces light, photosynthesis, and plant growth rates.
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Chemical contamination: many plastics release toxic compounds that alter the metabolism or endocrine system of organisms.
