The contribution of Hulene-B waste dump (Maputo, Mozambique) for the contamination of rhizosphere soil, edible plant, and stream and groundwater

Abstract

The contamination of ecosystems in areas around waste dumps is a major threat to the health of surrounding populations. The aim of this study is to understand the contribution of the Hulene-B waste dump (Maputo, Mozambique) to the contamination of edible plants, rhizosphere soils, stream waters, and groundwater, and to assess human health risk. Soil and plant samples were analyzed by XRD and XRF for mineralogical and chemical composition characterization, respectively. Mineral phases identified in rhizosphere soil samples were ranked, calcite (CaCO3) > quartz (SiO2) > phyllosilicates (micas and kaolinite) > anhydrite (CaSO4) > K feldspar (KAlSi3O8) > opal (SiO2·nH2O) > gypsum (CaSO4·2H2O), suggesting potential toxic elements low mobility. Soil environmental indices showed pollution by Pb > Cu > Zn > Zr. The chemical composition of edible plants revealed contamination by Ni, Cr, Mn, Fe, Ti, and Zr. Groundwaters and stream waters showed a potential health risk by Hg and, in one irrigation water sample, by Pb content. The health hazard index of rhizosphere soils was higher by ingestion, with children being the ones more exposed. Results suggested a combined health risk by exposure to edible plants, rhizosphere soils, stream waters, and groundwaters.