This study aimed to develop new techniques for the remediation of contaminated soils based on the application of zero-valent iron nanoparticles (nZVI) and bioremediation with compost from organic wastes and a mixed technique of both. An assessment of the effectiveness of remediation in two soils contaminated with hydrocarbons and heavy metals was carried out, with the aim of looking for positive synergies by combining the two techniques, and demonstrating their viability on an industrial scale. The application of nZVI for in situ immobilization of As and Cr in two different soils (Soil I from a contaminated industrial site and Soil II, contaminated artificially) showed a decrease in the concentration of As in Soil I and Soil II, as well as a decrease in Cr concentration for Soil I and Soil II in the leachate of both soils. The addition of compost and nanoparticles under uncontrolled environmental conditions in biopiles was able to produce a decrease in the concentration of aliphatic hydrocarbons of up to 60% in the two soils. Especially, degradation and transformation of longer chains occurred. A significant reduction of ecotoxicity was observed throughout the process in the biopile of soil II, not reaching the LC50 even with 100% of the sample after the treatment, in both earthworm and seeds growth tests

The physical-chemical characterization of plastic litter from the marine environment requires the prior removal of the biofouling attached to their surface without causing any degradation in the polymer. The absence of a standardized protocol for digesting biofouling and organic matter of both macro and microplastic samples extracted from seawater has been the main motivation for this research work, which aims to evaluate the effectiveness of different solvents (hydrogen peroxide, ethanol, a commercial enzymatic detergent, and potassium hydroxide) for the digestion of organic matter and biofouling in different samples recovered from the Spanish Atlantic and Mediterranean coast. Moreover, the potential effect of those solvents on the physical-chemical structure of polymers, four virgin plastic reference materials (low-density polyethylene, polyamide, poly(ethylene terephthalate) and polystyrene) without any type of prior degradation has been characterized in terms of Fourier transform infrared spectroscopy (FTIR) and optical microscopy. Results indicate that the hydrogen peroxide at 15% concentration applied for one week at 40 °C is the most effective solvent for organic matter and biofouling removal, without causing any apparent damage on the structure of plastic samples analyzed.

Azken hamarkada arte ez gara itsas ingurumenean mikroplastikoen (MPen) presentziaz kontziente izan. MPak itsaso eta kostaldeetan metatzen diren eta 5 mm baino tamaina txikiagoko plastiko-partikulak dira; zenbait produktu eta aplikaziotan erabilitako plastikozko material txikiak isurtzearen edo beste objektu handiago batzuen zatikapenaren ondorioz sortzen dira. Beraien arriskuaren benetako zenbaterainokoa ezezaguna da eta mundu osoan zehar jatorria, presentzia eta eraginak ikertzen ari dira. Lan honek MPei buruz munduan zehar egin diren hainbat ikerketa-lan bildu ditu, mundu-mailan itsas konpartimentu ezberdinetan MPei dagokienez aurkitu daitekeen egoera orokorra aurkezteko helburuarekin, mugak eta ezagutze-hutsuneak azpimarratuz. Itsaso-konpartimentu guztietan topatu dira MPak: ur-azalean, sedimentuetan (itsas hondoan, hondartzetan eta kostan, oro har) eta biotan; MP kopuruak nabarmenki aldatzen delarik behatutako konpartimentuaren, neurketa-teknikaren, eremu geografikoaren eta neurketa momentuaren arabera. Ikerketak alderatzeko zailtasunak nabarmentzen dira, erabilitako metodologia ezberdinak direla medio. Hori dela eta, prozedurak bateratzeko premiazko beharra dago. Mundu-mailan gehien ekoizten diren polimero motak izaki, polipropilenoa, polietilenoa eta poliestirenoa dira MPetan gehien azaltzen direnak. Ozeanoetako MPen banaketa eta eraginaren efektuei buruzko informazioa mugatua da oraindik. Horregatik guztiagatik, egindako lana sakondu beharra dago eskala ezberdinetan (lokalean, eskualdean eta mundu mailan): metodologiak adostu, monitorizazio-programak ezarri, iturriak hausnartu, MP sekundarioen degradazio-mekanismoetan sakondu, eta konpartimentuen arteko dinamikak eta ingurumenaren zein giza osasunaren gaineko eraginak aztertu.