## 3 Materials and Methods  
In the analysis, we focus on trace elements which are considered of anthropogenic origin. The macroelements, lithological and morphological parameters are used for the data interpretation and definition of the causes. Sediment samples were collected along the entire Baltic Sea coast of Lithuania in 2011, 2014, and 2018 (Figure 1). During the collection of samples, the sea and wind conditions were relatively constant. In the coastal zone, the most active processes occurred in the surf and swash zone; for that reason, it was decided to take samples from the middle of the beach [26]. Totally, 43 composite surface sand (0-5 cm) (from 5 subpoints) samples were collected at equal distances of 3 and 5 km and in plastic containers delivered for laboratory analysis [27]. In the laboratory, sand samples were air-dried and split to 100 g of sediment. The samples were mechanically sieved 15 min on a vibratory sieve shaker Fritsch Analysette 3 Spartan Pulverisette 0 using a set of 11 sieves. After determination of size fraction, statistical grain-size Falk and Ward method mean (d, mm), sorting (\(S_{\circ}\)) parameters were calculated using the GRADISTAT 8.0 software [59]. To characterize the relative concentrations of heavy minerals, a Bartington MS3 field scanning sensor was used for rapid and effective measurements of low-field volume magnetic susceptibility [27]. [PERSON] and [PERSON] [60] point out that bulk magnetic susceptibility (MS) is a good indicator of allochthonous mineral matter in sediments. Measuring MS helps to determine the net contribution of ferromagnetic and paramagnetic minerals in sediments. Heavy mineral-rich (\(\rho>2.90\) g/cm\({}^{3}\)) sediments have ferromagnetic and paramagnetic properties, and high magnetic susceptibility values, depending on the predominant iron content. Quartz-rich minerals (\(\rho<2.65\) g/cm\({}^{3}\)) have diamagnetic properties. Quartz-rich sands (dominate quartz, feldspar, carbonate, and mica group minerals) have weaker positive magnetic susceptibilities values of \(\kappa<3.0\) uSI, heavy mineral-rich sand (elements like Ti, Cr, Mn, Fe, Co, Ni, and Cu can sometimes result in magnetism) \(\kappa\) values range from 30 to 150 uSI and higher values \(\kappa>150\) uSI are typical for heavy minerals with Fe, Ni, and Co elements [26; 61; 62]. MS measurement method is helpful to detect ferromagnetic minerals when their concentration in sediments is deficient [60]. Magnetic susceptibility and grain sizes of beach sediments belongs of the provenance,geologic framework, alongshore sediment transport, deposition and coastal processes (erosion/accretion), etc. The grain size composition also might have contributed to the difference in proportions of ferromagnetic, paramagnetic, and diamagnetic minerals [63]. Magnetic minerals are known as important sources of trace elements in sediments. The beach sediment volume (\(Q\), m\({}^{3}\)/m) was calculated for each profile based on repeated cross-shore levelling once per year. The changes in sediment volume comprise the changes in volume of the coastal profile from the foredue lee side, where the vertical variability is negligible during observation, to the intersection with the mean sea level [12]. Total beach sediment volume was counted with the formula: \(Q=(Q_{i}+Q_{i}+1)\ L_{i}/2\), where \(Q\)--sediment volume (m\({}^{3}\)) at the coastal segment; \(i=1\), \(2\), \(3\), \(\ldots\) number of transects; \(Q_{i}\)--sediment volume at the separate coastal cross-section profile (m\({}^{3}\)/m); and \(L_{i}\)--distance between levelling cross-section profile lines [64]. For the geochemical analysis, the dried samples were ground using an agate mortar and pestle. Prior to each sample's homogenisation, the agate mortar and pestle were washed with deionised water and dried twice. Geochemical analyses of the samples were performed at the Bureau Veritas Commodities Canada Ltd., laboratory.