Avaluació del risc ecotoxicològic de llots de depuradores i purins (LODOTOX)

On a previous project some toxicity problems of sewage sludge currently applied to agricultural soil were detected. Chemical analysis of organic pollutans suggested that some of the identified xenobiotics may de responsible of toxic effects. In fact, bioassays over sewage sludge samples allows to detect genotoxic effects, plant growth inhibitions and disturbances on soil fauna composition. For this reason, in this new project we propose to study in depth about the toxicity problems of sewage sludge being applied to crop soils, trying to find easy and reliable standard methods, that can be useful like a soil ecotoxicity tests. This procedures will be applied to a representative set of sewage sludge and pig slurries, selected according their origin, composition and kind of treatment in a waste water plant. Results of the ecotoxicity tests will be compared to the analytical data of chemical analysis would be warranty enough as a control quality of sewage sludge and related residues. We propose, also, to study the effects of composting and thermal drying processes on the ecotoxicity of sewage sludge. Finally, we try to adapt and evaluate existing standard tests of toxicity to assess the environmental risk of this kind of residues that can be applied to soils