Use of bioassays for the assessment of areas affected by phosphate industry wastes

• Samples collected close phosphogypsum stacks had high toxicity.
• Samples collected near the estuary showed lower toxicity indices.
• The proposed set of bioassays is useful in the screening of the environmental risk.
• Low -cost bioassays proved reliable, sensitive and fast.

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.