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Phosphogypsum (PG) is a waste product of the phosphoric acid production process and contains, generally, high activity concentrations of uranium series radionuclides. This study is a contribution towards a risk assessment in areas affected by phosphate industry in SW Spain, integrating information from soil physicochemical characteristics, total and soluble potentially toxic elements (Zn, Pb, Cd, Cu, As and Fe), mineralogical composition and ecotoxicological evaluation. The applied bioassays confirmed the soil toxicity categorisation and then, it is highly recommended to complement the results from environmental chemistry with results from bioassays, in order to provide a more complete and relevant information on the bioavailability of contaminants and to characterise the risk of contaminated areas., Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub

This work presents a methodology to assess the environmental potential risk of soils when submitted to different conditions. The potentially toxic element (PTE) behaviour was evaluated by single chemical extractions in order to simulate four conditions: PTEs leaching under actual rainfall conditions; acid mine drainage; and an anoxic and an oxic environment. Soil pollution assessment was carried out using the contamination factor (CF) and the pollution load index (PLI) for total contents and indicators of mobility were established for each extraction: natural mobility indicator (NMI), acid mine drainage mobility indicator (AMI), oxic mobility indicator (OMI) and anoxic mobility indicator (ANMI). The total PTE content in the samples was high, and this content decreased when the distance of the sampling site to the source of contamination increased. The results obtained after the extractions suggested that the highest PTE content was extracted in the acidic medium. The mineralogical composition is an important factor that should be taken into account in the evaluation of PTE mobility, firstly because the mineral phases react differently in the proposed situations depending on their chemical nature, and secondly, because the presence of a particular phase (with different degree of reactivity) depends on the degree of weathering. The most reactive materials under oxic conditions are, in the study area, the most modern. The proposed indices may constitute a first attempt to define areas with high potential environmental risk, where urgent action is needed. In addition, the proposed methodology could be a valuable tool to prioritise these interventions., Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub