The Impact of Coastal Geodynamic Processes on the Distribution of Trace Metal Content in Sandy Beach Sediments, South-Eastern Baltic Sea Coast (Lithuania)

Featured Application Geochemical analysis can provide valuable information about the local and regional patterns of sediment transport, distribution, provenance, and coasts' conditions. Sandy coasts are one of the most dynamic spheres; continuously changing due to natural processes (severe weather and rising water levels) and human activities (coastal protection or port construction). Coastal geodynamic processes lead to beach sediment erosion or accumulation. The coast's dynamic tendencies determine the changes in the volume of beach sediments; grain size; mineralogical; and geochemical composition of sediments. In addition to lithological and mineralogical analysis of sediments, geochemical analysis can provide valuable information about the local and regional patterns of sediment transport, distribution, provenance, and coasts' conditions. The study aims to assess trace metals' temporal and spatial distribution determined in the sandy beach sediments along the south-eastern Baltic Sea coast (Lithuania) during 2011-2018. The Lithuanian seacoast is divided into two parts: mainland and spit coast. Our results revealed that the dominant group of elements on the mainland includes Ca-Mg-Mn-Ti and on the Curonian Spit Fe-Pb-As-Co-Cr-Ni-Al, which remain unchanged during the years. The analysis included additional parameters such as beach volume, grain size and sorting, and heavy mineral concentration on the beach. The spatial analysis of trace elements indicated that the trace metal content depends on the coastal processes, but it differs in the mainland and spit sea coast. We identified a higher concentration of trace metals in the erosion-dominated areas in all analysed years on the mainland coast. On the spit coast, the trace metal concentration increased in areas associated with relict coarse sand and where the loading of sediments was active on the beach due to the northward along-shore transport.

Automated summary

Geochemical analysis plays a crucial role in understanding sediment transport, distribution, provenance, and coastal conditions. Research conducted along the south-eastern Baltic Sea coast in Lithuania revealed different patterns of trace metal distribution in mainland and spit coasts, influenced by coastal processes. Erosion-dominated areas on the mainland coast showed higher trace metal concentrations, while active sediment loading areas on the spit coast had increased concentrations due to northward along-shore transport.