Evaluation of Sediment Dredging on Heavy Metal Concentrations in Mogan Lake’s Sediment (Ankara, Turkey)

Abstract

Sediment dredging (removal), a lake management method, is performed on a regular basis to improve the recreational value of Mogan Lake. The aim of the study is to a) determine heavy metal concentrations (Hg, As, Cd, Cr, Pb, Ni, Cu, and Zn) in the sediment after dredging and make evaluations based on the sediment quality criteria, b) define the potential sources of heavy metals by multivariate analyses, c) shed light on the effectiveness of the dredging in the context of current data. As indicated by the findings from two stations under the influence of mineral processing facilities (station I) and domestic wastewater discharges (station II) taken in May and November, 2020, the mean heavy metal concentrations in the sediment in decreasing order were Cr>Cu>Zn>Ni>Pb>As>Cd>Hg. Cr, Ni, and As levels were found to exceed the probable effect level (PEL) and therefore, the lake sediment was classified as heavily polluted in terms of Cr, Ni, Cu and As. Based on the Spearman’s correlation analysis, Cu-Cd, Zn-Pb, and As-Cd were found to have similar anthropogenic sources. Three main components determined by the principal component analysis also support this result; the differences in heavy metals originating from different anthropogenic sources reflect the environmental pollution diversity and pressure related to the heavy metal accumulation in the lake sediment. Based on our findings, sediment removal in Mogan lake can not be considered as effective intervention. As anthropogenic pollutants persist in the lake basin, sediment should be routinely monitored for heavy metal levels to ensure the lake's sustainable use.

Keywords

• sediment tarama
• sediment kalitesi
• ağır metal
• temel bileşen analizi
• mogan gölü