The current chemical composition of inland water bodies of the Volga-Akhtuba floodplain (Russia)

Abstract

The problem of clean water is one of the most important environmental problems in the world. It is impossible to prevent the occurrence of adverse environmental situations without careful monitoring of the aquatic ecosystems state. The assessment of the current chemical composition of the Volga-Akhtuba floodplain shallow channels (Peschanyj, Dudak, and Dudachenok) in the water-bottom sediments system was carried out. Studied shallow channels dried out during the summer-autumn lowwater period for the last few decades. Studies were carried out after the clearance and ecological rehabilitation of the shallow channels. It was found that almost all the studied indicators in water samples correspond to the established quality standards. There is uneven distribution of heavy metals in the studied shallow channels. It can be caused by the influence of hydrodynamic conditions, changes in water and sediment flow, as well as local factors, including the catchment heterogeneous geology. The analysis of the metals content in bottom sediments with permissible ones made it possible to detect excess for Hg (0.18?0.75 mg/kg), Cd (1?2.12 mg/kg), Mn (370.8?493.3 mg/kg), Ni (2.6?67.9 mg/kg), Pb (14.3?22 mg/kg), Zn (75.2?147 mg/kg). The content of As (1?1.4 mg/kg) and Cu (8.54?28.7 mg/kg) in bottom sediments does not exceed the permissible concentrations. The obtained results will form the basis for a general comprehensive assessment of the clearance and ecological rehabilitation of the Volga-Akhtuba floodplain watercourses. It is necessary to continue monitoring the watercourses state and strengthen efforts to preserve the resilient ecosystem of the Volga-Akhtuba floodplain.