The investigation of the water quality and bed-sediment conditions in Cutetchi Lake, Danube Delta, Romania

Abstract

Danube Delta includes many ecosystems functioning in a dynamic environment that could be considered, each of them, as ”natural laboratories”. In this sense, Cutetchi Lake was chosen for conducting practical investigations (August 2016) and the obtained data will be used to evaluate the impacts associated with natural factors or human-related activities. Water samples were investigated for physical parameters and water-quality constituents. Bed-sediments samples were analyzed for the main lithological components and trace elements to identify the levels, distribution and the potential sources of heavy metals in surficial accumulations. Related environmental standards were used to evaluate the water and sediment quality. Results indicate that, in the surface water the mean concentration of the environmental indicators ranged mainly in line with sampling points and generally agreed with reference standard: transparency (0.94 m), dissolved oxygen (8.98 mg/l), temperature (22.39 oC), conductivity (392.2 µS/cm), total dissolved solids (196.1 mg/l), pH (7.91), Eh (22 mV), turbidity (5.06 NTU), total suspended solids (9.25 mg/l), nitrite-nitrogen (0.01 mg/l), nitrate-nitrogen (0,02 mg/l), soluble orthophosphates (0.17 mg/l), sulphates (25,5 mg/l), silica (6,8 mg/l). The mean sediment parameter values were: moisture (23.13 %), dry sediment content (76.87 %), total organic matter (73.53 %), total carbonates (7.48 %) and minerogenic fraction (18.98 %). In the bed-sediment, the average metal content was: Zn (102.17 mg/kg), Ni (44.77 mg/kg), Cr (73.23 mg/kg), V (75.30 mg/kg), Co (9.38 mg/kg), Pb (24.83 mg/kg), Cu (58.70 mg/kg), Cd (0.82 mg/kg) etc., and individual values only incidentally exceed the maximum recommended level. This work could be a basis for the ongoing evaluation processes of water and sediment quality.

Keywords

• assessment
• bed-sediment
• Cutetchi Lake
• human impact
• water samples