Trace Elements in the Bottom Sediments of the Crimean Saline Lakes. Is It Possible to Explain Their Concentration Variability?

Abstract

Knowledge of trace elements content and their behavior in aquatic ecosystems is important for their sustainable use. There is a lack of such data for saline and, especially, hypersaline lakes and lagoons. Concentrations of more than 20 elements were evaluated in bottom sediments of 15 saline/hypersaline lakes and Lagoon Sivash in Crimea. An average salinity varied from 4 to 335 g/L in studied water bodies. The concentration of the trace elements varied from lake to lake. The highest variability was recorded for Cd, from 4.13 mg/kg to below the detectable level (CV = 1.463), and for Se, from 5.52 to 0.05 mg/kg (CV = 1.053). The lowest variability demonstrated by Cr, from 368 to 17 mg/kg (CV = 0.463), and by V, from 67.8 to 1.7 mg/kg (CV = 0.481). According to the found content of studied elements, all lakes were separated into three groups, and Lagoon Sivash was not included in these clusters. Salinity affected the concentration of some elements in bottom sediments, and this effect was not linear or unidirectional. In some cases, the action of other factors, often unknown, masked the effect of salinity. The geochemical background affects the structure and functioning of aquatic ecosystems, but the state of these ecosystems can significantly modify this background. An understanding of the differences in the elemental composition of bottom sediments in different lakes is possible only based on an integrated consideration of the interaction of all landscape, intra-ecosystem, and anthropogenic processes and factors that can influence this.

Characteristics of Bottom Sediments in the Coastal Areas of the Crimean Peninsula

“…During the cruises on the RV "Professor Vodyanitsky" in the autumn of 2018 and summer of 2019, complex studies were carried out, including an analysis of the hydrochemical characteristics of the water column and geochemical characteristics of bottom sediments in the coastal areas of the Crimean Peninsula (Figure 1). ying the features of the accumulation and spatial distribution of various pollutants in the water areas of the Crimean shelf [2,4,25] and closed and semi-closed lagoons [26,27]. Some works [28,29] are devoted to the study of the vertical profiles of the key redox species in pore waters of the bottom sediments obtained by voltammetry.…”

“…Earlier studies are reflected in the works of [23,24]. Currently, the geochemical characteristics of bottom sediments arouse great interest within the framework of studying the features of the accumulation and spatial distribution of various pollutants in the water areas of the Crimean shelf [2,4,25] and closed and semi-closed lagoons [26,27]. Some works [28,29] are devoted to the study of the vertical profiles of the key redox species in pore waters of the bottom sediments obtained by voltammetry.…”

Toxic Metals, Non-Metals and Metalloids in Bottom Sediments as a Geoecological Indicator of a Water Body’s Suitability for Recreational Use

“…22.0-203.0 mg/kg Três Marias Reservoir (Brasil)-2.0-150.6 mg/kg [71]; Dianchi Lake (China)-68.6-95.3 mg/kg [72]; Orlík Reservoir (Czech Republic)-72.4-123 mg/kg (108 mg/kg-average) [73]; Mujib Reservoir (Jordan)-79.8-136.8 mg/kg (114.2 mg/kg-average) [74]; ponds in Kolkata (India)-up to 882.2 mg/kg [75]. Yangebup Lake (Australia)-21.8 mg/kg (average) [76]; Badovci Lake (Kosovo)-10.0-29.9 mg/kg (24.2 mg/kg-average) [64]; Ro żnów Lake (Poland)-5.2 mg/kg (average) [77]; 15 lakes located on the Crimean Peninsula-from 3.05 mg/kg (Dzharylgach Lake) to 20.41 mg/kg (Adjigol Lake) [78].…”