Impact des Décharges Sauvages des Déchets Solides sur les Sols à Cotonou

Abstract

The management of household-based waste in Benin is characterized with the existence of several steps including dumping (disposal at approved landfill site) which is one of the most important. The assessment of waste processing method in the approved landfill site of Ouessè in terms of environmental quality safeguard is the main objective of this paper. Main methodological steps consist of joint sampling and in-field investigations involving grassroots stakeholders. Besides, the analysis of the concentration level of parameters such as COD, BOD5 as well as heavy metals in both surface and underground waters have been essential to the methodological step. Analysis of results shows that there are no indications of lixiviation matters being migrated. In fact, potable water as sampled in the area under review contains only coliforms with a concentration ranging from 01 to 6400 colon bacillus per 100 ml. As per surface water-based analysis, it shows that both values of BOD5 (5 mg/L of O2 against 8.54 mg/L of O2 for standard), and COD (3 mg/L of O2 against 5 mg/L of O2) - downstream are below the standard limit (100 mg/L of O2). The trend is the same as for heavy metals including nitrogen (200 mg/L), nickel (2.5 mg/L) and chromium (<0.1 mg/L).