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Research Paper | Soil and Water Science | Congo | Volume 12 Issue 9, September 2023

Speciation and Pollution Assessment of Chromium and Zinc in Landfill Soils of Brazzaville: Physico-Chemical Analyses and Heavy Metal Contamination

Engambe Christ Bardoul | Tchoumou Martin | IFO Grace Mazel | Moussoki Nsona Promesse

Abstract: The aim of this work is to study the speciation of chromium and zinc, and their pollution in the soil of landfills in Brazzaville. In each site studied ( Glaci?re, Moukondo and Tsi?m?), soil samples were taken from different points and then mixed to obtain a composite sample which underwent some physical treatments before proceeding to the various analyses. Physico-chemical parameters: pH, electrical conductivity and organic matter were determined, and concentrations of Chomium and zinc The results of physicochemical analyses showed that soils have neutral pH between 6.92 and 7.02 and that the organic matter content varies between 1.72 and 7.24%. The results of the determination of heavy metals by inductively coupled plasma-optical emission spectrometry showed that chromium is present in large quantities compared to zinc and that the Tsi?m? landfill contains large quantities of these two heavy metals. Studies of sequential extractions showed that chromium is more bound to the exchangeable and acid-soluble fractions while more than half of zinc is bound to the exchangeable fraction. The pollution intensities expressed by the contamination factor (CF) and the geo-accumulation index (Igeo), indicated that the soils of all landfills are largely polluted by zinc and pose a risk to the environment.

Keywords: Landfill, pollution index, sequential extraction, contamination factor, geo-accumulation index

Edition: Volume 12 Issue 9, September 2023,

Pages: 731 - 739