Caractérisation de la qualité physico-chimique des effluents et sédiments de carrière de la société CARRIGRES à Kinsuka Pêcheur dans la ville de Kinshasa (RD Congo)

Publication Date : 10/04/2026

DOI: 10.59228/rcst.026.v5.i2.256

Author(s) :

Samuel Kabengele Mayimbi, Willy Swana Lusasi , Fils Empwal Milau, Michel Lufuluabo Kapembo, René Valu Gizanga.

Volume/Issue :

Volume 5

Issue 2

(04 - 2026)

Abstract :

Quarry exploitation has intensified due to urban expansion and growing demand for construction materials in the city of Kinshasa in the Democratic Republic of Congo. The aim of this study is to characterize the physicochemical quality of effluents and sediments from the CARRIGRES quarry, as well as the water of the Congo River at the discharge point, in order to highlight the influence of effluent discharge from this activity on the quality of the receiving environments. The quality of effluents and sediments was monitored through in situ sampling for some parameters and laboratory testing for other physicochemical parameters between February and October 2025. In the laboratory, the parameters of interest were determined using an X-ray fluorescence spectrophotometer and a UV spectrophotometer. The results obtained show that the concentration of certain physicochemical parameters in the effluents and sediments from the CARRIGRES quarry are inconsistent with the standard values set by the WHO, with the direct consequence of a deterioration in the physicochemical quality of the water in the Congo River for certain parameters. Among the most worrying parameters are turbidity (effluent discharge = 183.4±2.8 UNT, sump = 182.1±1.1 UNT and raw effluent = 161.5±1.1 UNT), biochemical oxygen demand (sump = 69.02±0.21 mg/L and raw effluent = 63.05±0.14 mg/L) and phosphate ions (discharge = 3.41±0.03 mg/L, Sump = 3.17±0.07 mg/L and raw effluent = 2.89±0.03 mg/L), reflecting a significant load of suspended solids and substances likely to alter the ecological balance of the receiving environment. Analysis of heavy metals reveals a notable accumulation of certain heavy metals, in particular Pb, Al, Cr, and Ni. The raw effluents from the sump and discharges are biodegradable and had biodegradability indices of between 1,5 and 1,6. The optimization and/or installation of a suitable treatment system at CARRIGRÈS will help to reduce the loads of suspended solids, nutrients, and heavy metals before discharge.