Dataset contains geochemistry data from the Romanian shelf. Data were collected onboard R/V Mare Nigrum, during a cruise conducted in August 2021, within the national project "Multidisciplinary research to improve knowledge of the climate change and human pressure interaction and its effects on the Black Sea ecosystem" – PN 19 20 01 02. Thirty stations distributed along 4 main transects (Sf. Gheorghe-SE, Portita-SE, Constanta-SE, and Mangalia-E) were performed for sediment investigations by the GeoEcoMar team. Sediment samples were collectyed using Van Veen grab sampler and Multicorer MARK II-400, and analyzed for major and minor components as well as trace elements (by X-ray fluorescence) and total mercury in the GeoEcoMar lab.