The speciation and potential mobility of Pb, Cd, Cu and Zn in lake Qarun bottom sediments, Fayioum, Egypt

Abstract EN

The total concentrations and the solid phase speciation of lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn), in the bottom sediments from Lake Qarun, Fayioum, Egypt was determined.

Besides, the total concentrations of the scavenging metals Fe and Mn were determined.

The crustal enrichment factor (EFcrustal), the contamination factor (Cf), the modified degree of contamination (m Cd), the metal pollution index (MPI), as well as the geoaccumulation index (Igeo).

The aim of this work is to investigate the solid phase fractionation distribution of certain hazardous heavy metals and to assess their potential mobility from sediment to water the concentrations’ ranges of Pb, Cd, Cu, Zn, Mn and Fe were 14.0-40.4 μg / g, 0.5-7.6 μg / g, 18.4-62.6 μg / g, 46.5-232.5 μg / g, 131.9-587.3 μg / g and 6.4-40.2 mg / g, respectively.

The total concentrations of heavy metals showed levels as normal as uncontaminated sediments, except Cd which was slightly higher than the natural levels.

Most of the concentrations of Pb (~70 %), Cu (~66 %) and Zn (~58 %) were in the immobile fractions of the solid phase (inert fraction) and they had little hazardous impact on the environment.

On the other hand, Cd is enriched in the mobile phase of the sediment (reactive fraction) and strict measures should be applied to reduce or prevent the cadmium bearing discharges into the lake.

The trace metals flux to Lake Qarun sediments is mainly from allochtonous origin.

The most probable discharge sources are the agricultural drains, the wastes of fish farms and the municipal wastewaters from the surrounding urban and rural communities.