International Journal of Environmental Science and Development

Abstract—In the Republic of Congo, solid waste from households and small industries of all kinds is dumped without prior treatment in public landfills, often in the open. The soil in these landfills is not protected and is therefore at risk of contamination by heavy metals. As a result, the surface water and groundwater in the surrounding area are also exposed to the same risks through various phenomena, since the storage of solid waste is the cause of large quantities of heavy metals being buried in the soil. Against this background, this study was carried out to assess the environmental impact of waste deposited in open dumps in the city of Brazzaville. Soil samples were taken from open dumps at four sites (Kinsoundi, Diata, Moukondo and Tsiémé). Physicochemical analyses such as pH, water content (TE), Organic Matter content (MO) and heavy metal content were carried out on soil samples from landfills at these four sites. Soil organic matter content was determined using the Walkley and Black method, while heavy metal content was measured using ICP-OES. The results showed that the investigated landfill soils are slightly alkaline (6.93–7.29) with low water content (12.53–18%) and rich in organic matter (1.38–5.45%). The soils also contain high levels of heavy metals: Cr (1724.67–6664.64 mg/kg), Hg (0.78–1.53 mg/kg), Pb (120– 173.33 mg/kg) and Zn (920–5500 mg/kg). The values of the geoaccumulation index (1.72–5.63) and the pollution index (5.10– 16.40) show a significant contamination of these soils by the above-mentioned heavy metals. Statistical processing using the correlation matrix was used to establish a series of relationships between the different parameters studied.

Keywords—heavy metals, contamination, pollution, landfills, environment, geo-accumulation index

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Cite: Engambé Christ Bardoul, Kouhounina Banzouzi Merline Lady, Bibila Mafoumba Jean Claude, Kounampo-OKouo Avinth Carmel, Moussoki Nsona Promesse, and Tchoumou Martin, "Assessment of the Intensity of Soil Pollution of Open-Air landfills by Heavy Metals (Cr, Hg, Pb and Zn) in the City of Brazzaville, Republic of Congo," International Journal of Environmental Science and Development vol. 16, no. 1, pp.  58-64.

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