Distribution of trace elements and radionuclides in the Curonian Lagoon and the Baltic Sea

Abstract

This study presents the distribution of trace elements (Hg, Cd, Pb, Cr, As, Cu, Ni, Zn, Co, V, Al, Li), organic carbon, δ 13 C org and radionuclides ( 90 Sr, 137 Cs, 239,240 Pu, 241 Am) in the Lithuanian part of the Baltic Sea and the Curonian Lagoon. Particulate matter (PM) and bottom sediment samples were collected during the sampling campaigns in the frame of the State monitoring and during several other investigations over the period of 1997-2011. The study area is characterized by variable loading with particulate matter. Averaged concentrations of the particulate matter in the water of the Curonian Lagoon area tended to be approximately 3 times higher in comparison with those measured in the Baltic Sea. Results showed a strong relation between metals and organic carbon in particulate matter (r=0.69-0.98, p<0.05). The correlation between metals and organic carbon in sediments was not so strong and varied in the range of 0.45-0.84. It was found out that the highest concentrations of trace elements in the Baltic Sea accumulated in the deepest stations of R7, 12A, 46 with the fine-grained, organic-rich sediments. Pollution was strongly pronounced in the Curonian Lagoon (including Klaipeda Strait area), elevated concentrations of metals were also measured in sediments of the plume of the Lagoon water, dumping of dredged material areas and in the aleurite sediments in the Baltic Sea. Higher level of elements accumulated in the surface sediments (0-3 cm), the difference between core layers was more evident at the deepest stations. According to the results, higher concentrations of radionuclides accumulated in PM and sediments as compared to marine water. The correlation of 137 Cs, 239,240 Pu and 241 Am with total organic carbon in bottom sediments was found to be 0.75-0.98. δ 13 C org in particulate matter, surface bottom sediments and humic substances of the Curonian Lagoon and the Baltic Sea ranged from -22.3 ‰ to -31.8 ‰. δ 13 C org values in the bottom sediment samples well correlated with δ 13 C org values in PM and humic acid samples.

Sediment Transport Mechanisms in a Lagoon with High River Discharge and Sediment Loading

“…In the lagoon, the highest TSS (20-57 mg L −1 ) and SSC values were found in the summer-autumn season, together with the algal bloom or when the cyanobacteria were dominant. This is in agreement with other Curonian Lagoon studies, where the TSS were measured for the ice-free season [60,63], and the highest concentrations were found by [64] with the maximum TSS of 304 mg L −1 (in the article called particulate matter) during the summer-autumn season, due to high plankton concentrations. In most of the analyzed studies for the Baltic Sea lagoons and other regions, only the TSS values were measured.…”

Nutrient Loadings and Exchange between the Curonian Lagoon and the Baltic Sea: Changes over the Past Two Decades (2001–2020)

“…The area of this study includes the Lithuanian part of the Curonian Lagoon (CL), the Klaip ėda Strait (KS), and the Baltic Sea nearshore (BS, Figure 1). The Curonian Lagoon is a shallow semi-enclosed freshwater lagoon separated from the Baltic Sea by the Curonian Spit [25]. The circulation of water in the Curonian Lagoon is primarily influenced by the discharge of the Nemunas River and the direction of the wind [26].…”

“…Moreover, the Nemunas River transports around 342,000 metric t of particulate matter into the lagoon through its tributaries [29]. The southern and central parts of the Curonian Lagoon are freshwater (<0.5 psu), while the northern part is oligohaline with irregular salinity (from 0 to 8 psu) fluctuations [25]. The northern part of the Curonian Lagoon connects the lagoon with the Baltic Sea through the Klaip ėda Strait, which is characterized by a large technogenic and anthropogenic load [29][30][31].…”

Δ14C and δ13C Variations in Organic Fractions of Baltic Sea Sediments

“…The intrusions of the Baltic Sea water to the Curonian Lagoon via the Klaipeda Strait due to fluctuations of the water level and hydrometeorological conditions can cause an increase in salinity from 0.5 to 8‰. Details on the sampling area and sediment characterization are given in previous publications (Lujanienė et al 2005(Lujanienė et al , 2013Remeikaitė-Nikienė et al 2012). Sediments were collected using a Van Veen grab during sampling campaigns in the framework of the state monitoring programs in 2012-2014, as well as during two expeditions to the CWA dumping site located in the Gotland Deep (Figure 1), which were carried out in 2013 and 2014.…”