Impact of chlorophenols and heavy metals on soil microbiota: their effects on activity and community composition, and resistant strains with potential for bioremetiation

Pollution by toxic compounds is one of the most relevant environmental damages to ecosystems produced by human activity and, therefore, it must be considered in environmental protection and restoration of contaminated sites. According to this purposes, the main goal of this doctoral thesis has been to analyse the impact of several chlorophenols and heavy metals on the microbial communities of two typical Mediterranean soils. The ecological risk concentrations of each pollutant, which have been determined according to respirometric activity and changes in the microbial community composition, and the factors that influence on their effective toxic concentrations (bioavailable pollutants) have been analysed in order to predict their potential impact on different soil ecosystems and provide scientific data for the regulation of the soil protection policies. Moreover, resistant microorganisms with pollutant removal capacities have been isolated from artificially contaminated soil microcosms and tested in axenic cultures, to infer their potential usefulness for bioremediation.

Valorisation of industrial wastes for the removal of metals and arsenic from aqueous effluents

En la presente tesis se han realizado estudios de eliminación de metales pesados y arsénico de aguas contaminadas mediante procesos de adsorción sobre materiales de bajo coste. Dichos materiales son, en todos los casos, subproductos de industrias agroalimentarias o metalúrgicas.La tesis consta de diferentes capítulos enmarcados en tres secciones: (i) Eliminación de cromo hexavalente y trivalente (ii) Eliminación de cationes divalentes de metales pesados en presencia de complejantes y en mezclas multimetálicas y (iii) Eliminación de arsénico utilizando un subproducto de la industria de cromados metálicos como adsorbente. Los resultados obtenidos ponen de manifiesto que ciertos residuos industriales pueden ser utilizados como adsorbentes en la detoxificación de efluentes contaminados con metales pesados. La tecnología propuesta representa una alternativa sostenible y de bajo coste frente a los tratamientos actuales más costosos y dependientes, en muchas ocasiones, de productos derivados del petróleo.