In this study, the contamination profile of heavy metal levels (Cd, Cu, Fe, Hg, Pb, Zn) of Treptacantha barbata (Stackhouse) Orellana & Sansón, 2019, seawater and sediment samples were analyzed by ICP-MS and reference materials were used to determine the reliability of the analysis. All samples were collected from the Sinop coast (Türkiye) from August 2021 through April 2022. As a result of the study, metal levels were found in the following sequence: Hg < Cd < Pb < Cu < Zn < Fe for seawater and T. barbata and Hg < Cd < Cu < Pb < Zn < Fe for sediment. Among the metals, Cu was bio-accumulative in biota; Cd and Hg metals in the sediment are micro concentrator by T. barbata.