Spatial Distribution and Ecological Risk Assessment of Trace Metals in Surface Sediments of Lake Qarun Wetland, Egypt

Abstract

Wetlands sediments could be critical indicators to control contamination in the aquatic ecosystem. Qarun Lake is regarded as the third biggest lake in Egypt that is not related to any sea. Twelve georeferenced sediment samples were gathered in September, 2020 from the different locations. Five heavy metals (Pb, Cd, Cr, Ni, and Co) were measures in the sediments estimated by Atomic Absorption Spectrophotometer. Grain size and content of organic matters in the sediment were estimated on the basis of standard assays, as well as the contamination factor, geoaccumulation index, ecological risk factor, contamination degree and potential ecological risk index in the sediment. Data revealed that the average concentration could be arranged as Ni (27.36 mg k g^-1) > Pb (18.28 mg k g^-1) > Cr (15.31 mg k g^-1) > Co (11.16 mg k g^-1) > Cd (23.31 mg k g^-1). Cd, Co and Pb were estimated to be in the range of EU (2002) and the US EPA (1999), while Co and Ni in the range of EU (2002). The ecological risk index (Er) of the studied elements in sediments of lake could be arranged as: Ni > Pb > Co > Cd > Cr. In addition, the highest-integrated potential ecological risk was on the south side of the lake, which is subjected to huge amounts of drainage water composed of organic and inorganic pollutants.