Assessment of polonium-210 bioaccumulation in Mediterranean limpet Patella caerulea (Linnaeus, 1758) and sea urchin Paracentrotus lividus (Lamarck, 1816) from different coastal areas of Türkiye: Inclusion of a seasonal investigation

This study investigated the seasonal variations of polonium-210 (²¹⁰Po) activity concentrations in two marine invertebrate species: Mediterranean limpet (P. caerulea) and the sea urchin (P. lividus). Seasonal sample collection was conducted across three Aegean and Sea of Marmara coastal stations from December 2018 to October 2019. The stations included İzmir-Urla, Karaburun, and İstanbul Island-Kınalıada. To assess the size-dependent bioaccumulation of ²¹⁰Po, individuals were categorized into size groups. The activity concentrations in both species exhibited seasonal fluctuations, ranging from 4.9 ± 3.4 Bq kg⁻¹ dry weight to 28.0 ± 8.4 Bq kg⁻¹ dry weight in Mediterranean limpets and 8.7 ± 6.1 Bq kg⁻¹ dry weight to 58.0 ± 18.5 Bq kg⁻¹ dry weight in sea urchins. The highest ²¹⁰Po activity concentrations were consistently observed in spring across all sampling locations.