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The application of pesticides is a common practice for pest control. Either its excessive use or by performing improper farming practices, the occurrence of residual levels of these compounds in soil has become a global issue due to their negative impacts on environment and human health. This work was aimed to assess the effectiveness of ozonation technique for the remediation of soils polluted with boscalid, chlorantraniliprole, flonicamid and metribuzin residues at field conditions and the impact of its application on microorganism activity of the soil. Trial was conducted in plots located in a greenhouse, exposing polluted soil to different treatments during the winter season. Four different treatments were applied: S (soil covered with polyethylene film), SOD (film covering and deep-ozonation), SOSD (film covering and superficial-deep-ozonation) and C (no treatment, control). Better degradation efficiency was found for SOSD treatment (dual ozone application), where remaining percentages ranged from 13.2 % to 33.1 %. The main transformation products (TPs) were monitored through the remediation experiment, showing residual levels of six intermediates in all treatments. Further, the overall activity of the soil microbial community was evaluated through basal respiration, with SOSD showing the greatest microbial activity. The results suggest that ozonation could be proposed as an alternative technical approach for the remediation of pesticide polluted soils.

Our aim was to evaluate the long-term influences of urban organic amendments on the enzymes involved in the carbon cycle under semi-arid conditions, including changes in the biomass and structure of the microbial community. A soil was restored 24 years ago with an organic amendment based on domestic organic waste. Organic amendment was applied to soil in order to increase the content of total organic carbon (TOC) by 0.5% and 1.5% with respect to the original TOC content. Enzyme isoform composition was studied by using zymographic techniques based on protein extraction, separation by gel electrophoresis and further enzyme-specific, in-gel staining. Total cellulose and β-glucosidase activities, microbial biomass estimated by phospholipid-fatty acid analysis and the number of isoforms of each enzyme showed increases related to the initial amount of organic amendment and the consequent development of vegetation. The information obtained by enzyme activity assays may be improved by the use of zymographic techniques, which allow the investigation of the variety of isoforms of each enzyme. This information could improve the understanding of the relationship between the microbial community and carbon cycling in restored areas.

The sequence of formation and propagation of structures, as well as the evolution of crustal thickening, in the Variscan belt of northwest Spain are proposed in this paper. The foreland of this mountain belt shows thin-skinned tectonics. A polyphase deformation with associated regional metamorphism is recognized in the hinterland zones. Two important culminations, the Narcea and Lugo antiforms, are present in an E-W cross-section through the footwall to the suture of this orogen. Such culminations are derived from the stacking of several thrust systems generated during two successive periods. The sequence of thrust emplacement helps to clarify the formation of different types of structures at the same time in different places in the orogen.