Diagnostic et évaluation de la dégradation des sols par le lixiviat du Centre d'enfouissement Technique (C.E.T.) de Sidi Benadda.

Abstract

Municipal solid waste management through landfilling generates highly polluted leachates rich in organic matter, dissolved salts, and heavy metals, posing a severe threat to ecosystem sustainability in semi-arid zones. This introductory research work evaluates and diagnoses the potential impact of these effluents on the degradation of six agricultural soil horizons located near the Sidi Benadda Landfill (CET) in the Wilaya of Aïn Témouchent. The assessment of the intrinsic vulnerability of these soils, based on their physicochemical, geotechnical, and structural properties, reveals highly heterogeneous behaviors regarding pollutant migration or retention risks:  High Resilience Zones: Soil 6 emerges as the most resilient profile. Its exceptionally high organic matter (OM) content (9.02%) combined with high porosity (57.0%) grants it an excellent adsorption capacity, allowing it to act as a protective natural filter against contaminant migration.  Critical Vulnerability Zones : Conversely, Soil 2 exhibits the highest environmental risk. Its extreme depletion in organic matter (1.29%), low porosity, and fragile structural stability severely limit its buffering capacity, promoting either vertical pollutant leaching toward the groundwater or lateral runoff.  Intermediate Dynamics : Soils 1, 3, 4, and 5 displays satisfactory organic matter levels (between 4.7% and 6.3%). However, a strong negative correlation (-0.82) between clay activity and organic matter indicates that a higher clay fraction in certain profiles tends to reduce permeability while diminishing overall retention capacity. Furthermore, the high porosity of Soil 1 (59.1%) raises concerns regarding rapid transport under massive pollutant loads. Given these risks of structural and chemical degradation, and despite the presence of an on-site leachate treatment plant, a regular monitoring network for both soils and groundwater is imperative.

Finally, sustainable management practices - such as applying organic amendments to nutrient- deficient profiles like Soil 2 - are strongly recommended to enhance filtration capacity and restore

the fertility of this agricultural heritage.