A full picture of the exposure to emerging compounds requires detailed information on their mobility and availability. This information can be gained with non-conventional techniques such as DGT (Diffusion Gradients in Thin films), which can be used to measure receiving fluxes at limiting consuming surfaces of both organic and inorganic contaminants. For both contaminants, total concentrations are expected to exhibit poor correlation with uptake due to the interactions of these compounds with sediments, particles, organic matter or other ligands present. For metals, complementary information can be gained with AGNES (Absence of Gradients and Nernstian Equilibrium Stripping), which provides free cation concentrations. Our laboratory develops and implements the so-called speciation techniques to various matrices (ranging from soils to river or seawater) and analytes, with focus on providing an interpretative framework for their results. Our research on the dissolution of ZnO nanoparticles has had a broad impact in the specialized community. Our interpretation of the DGT accumulations when the passive samplers were deployed on top of a Seaexplorer glider allowed to retrieve lability degrees in the open sea. Our technique AGNES is able to determine, for instance, free indium concentrations or the concentration of antimony hydroxides. Our expertise in various kinds of modeling is widely recognized.
The Environmental Physico Chemical Group at the Universitat de Lleida (UdL) is a research unit with expertise in environmental chemistry, analytical chemistry and physical chemistry. Our studies include the thermodynamic modelling of speciation with Dissolved Organic Matter (where we contributed with the concept of Conditional Affinity Spectrum), Dynamic aspects of metal behaviour (we introduced the concept of lability degree), Dissolution, aggregation and settling of nanoparticles and the development of speciation analytical techniques (AGNES, DGT, DMT, DIET, etc. ). We have projects running at national and European levels.