The article presents data on heavy metal -Hg, Pb, Cd and Zndistribution in the layers of marine sediments from the off-shore areas of the southern Baltic Sea: Gdańsk Deep, SE Gotland Basin and Bornholm Deep. Depth profiles of metal concentrations were converted to time-based profiles using the 210 Pb dating method and verified by 137 Cs distribution in the vertical profile. The linear sedimentation rates in the Gdańsk Deep and SE Gotland Basin are similar, 0.18 cm yr À1 and 0.14 cm yr À1 ,

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... ctively, while the region of the Bornholm Deep is characterized by a greater sedimentation rate: 0.31 cm yr À1 . Regarding anthropogenic pressure, Gdańsk Deep receives the largest share among the analyzed regions. The maximal metal concentrations detected in this area were Zn -230 mg kg À1 , Pb -77 mg kg À1 , Cd -2.04 mg kg À1 and Hg -0.27 mg kg À1 . The least impact of anthropogenic pressure was noticeable in SE Gotland Basin. The combination of sediment dating with the analysis of vertical distribution of heavy metals in sediments benefited in the determination of target metal concentrations used in environmental status assessments. Reference values of heavy metal concentrations in marine sediments were determined as: Zn -110 mg kg À1 , Pb -30 mg kg À1 , Cd -0.3 mg kg À1 and Hg -0.05 mg kg À1 from the period of minor anthropogenic pressure. Basing on the determined indices: enrichment factor Peer review under the responsibility of Institute of Oceanology of the Polish Academy of Sciences.