This study established background (pre-industrial) values of copper (Cu), arsenic (As), cobalt (Co), and uranium (U) in Baltic Sea sediments. The indicated background values could help identifying the spatial and temporal anthropogenic loads of these elements (metals and metalloids) in the Baltic Sea. In this study, 137 sediment samples were collected from cores obtained from 13 monitoring stations in the Gulf of Bothnia (Bothnian Bay and Sea) and the entire Baltic Proper. To understand the extent of contamination, we used direct and combined methods to define the geochemical background values as inputs for the geochemical index (I_geo) calculation. The obtained values were then compared with the background values established by the Swedish Environmental Protection Agency. From the direct method, Cu, Co, As, and U had background values of 39, 21.5, 12.4, and 6.3 mg kg⁻¹ DW. Copper and U exhibited concentrations above the background values in surface sediment in the western and eastern Baltic Proper (maximum I_geo indicates moderate contamination). Arsenic was above background concentrations in the Baltic Sea and highest in the Gulf of Bothnia (maximum I_geo indicates strong contamination). Cobalt concentrations were within the range of background values (no contamination).

本研究确定了波罗的海沉积物中铜 (Cu)、砷 (As)、钴 (Co) 和铀 (U) 的背景（工业化前）值。指示的背景值有助于确定波罗的海中这些元素（金属和准金属）的空间和时间人为负荷。在这项研究中，从波的尼亚湾（波的尼亚湾和海）和整个波罗的海地区的 13 个监测站获得的岩心收集了 137 个沉积物样本。为了了解污染程度，我们使用直接和组合方法将地球化学背景值定义为地球化学指数（I _geo） 计算。然后将获得的值与瑞典环境保护局确定的背景值进行比较。根据直接方法，Cu、Co、As 和 U 的背景值为 39、21.5、12.4 和 6.3 mg kg ^-1 DW。铜和 U 的浓度高于波罗的海西部和东部表层沉积物中的背景值（最大 I _geo表示中等污染）。砷在波罗的海高于背景浓度，在波的尼亚湾最高（最大 I _geo表示严重污染）。钴浓度在背景值范围内（无污染）。