Application of Geophysics in geo-environmental diagnosis on the surroundings of the Hulene-B waste dump, Maputo, Mozambique

Abstract

This study aims to identify superficial and underground heavy metals contamination and outline contamination plumes on the surroundings of the Hulene-B waste dump. The electrical resistivity method was applied in 4 profiles of 400 m, 2D resistivity. The interpretation of the resistivity values allowed to identify three anomalous zones with possible contamination: (i) North (profile 2) with East-West orientation, perpendicular to the waste dump with resistivity values < 30.0 Ω m; (ii) West of the waste dump and Northwest (profiles 1 and 3), with an orientation parallel the waste dump, with resistivity values of <21.9 Ω m; and (iii) Southwest (profile 4) with perpendicular orientation to the waste dump with resistivity of <14.7 Ω m. Thus, the most notorious anomalies in the western limit (profiles 1, 2 and 4) can be associated with soil and subsoil contamination by heavy metals associated with possible contamination plumes that show a movement to the east-west direction and dissolve when in contact with the groundwater in the south and center of the depressive area. Results of the analysis of the spatial distribution of anomalous values show a decrease with distance from the main source of contamination - the Hulene-B waste dump.