Özet:

Dredging, a practice intended to increase the recreational value of aquatic systems at risk of eutrophication, has been implemented in Lake Mogan. This study aimed to determine a) Heavy metal concentrations (Hg, As, Cd, Cr, Pb, Ni, Cu, and Zn) in the overlying water and sediment pore water, and b) Pore water toxicity levels of some of these metals (Cu, Ni, Pb, Zn) following dredging in Lake Mogan. Surface sediment samples were taken from two stations in the lake between May and November 2020 to obtain overlying water and pore water values. The first station was chosen specifically because it receives wastewater from mineral processing facilities and nearby households; and the second station. After all, it receives household and industrial waste and agricultural wastewater. The findings indicate that a) Zn had the highest concentrations during the study period, and Pb the lowest. Overlying water concentrations were found to be within the acceptable limits outlined by the “Water Quality Control Regulations”. Pore water Zn concentrations for May (330.50±8.72 µg L-1) and pore water Cu concentrations for November at the second station (12.85±4.35 µg L-1) were higher than the recommended WQC limits. b) Since no values greater than 1 were found in the pore water for IWCTU (Interstitial Water Criterion Toxic Units) and NI (Nemeraw index) values for Ni, Cu, Zn, and Pb, no serious levels of pollution were present for these four metals; however, Zn had the greatest potential risk of toxicity. Moreover, the total IWCTU and NI values indicate that both the toxicity of the metals and the degree thereof increased in May. The fact that pore water heavy metal concentrations in Lake Mogan were generally higher than those in the overlying water indicates strong metal adsorption in the sediment and suggests that, at least in terms of reducing surface sediment heavy metals, dredging activities in the lake are not very effective.

Anahtar Kelimeler: