Hanna Research Group

The mobility of pharmaceuticals in environmental systems is under great scrutiny in the scientific literature and in the press. Still, very few reports have focused on redox-driven transformations when these compounds are bound to mineral surfaces, and how their transport is affected under flow-through conditions. In our works, we examined the adsorption and electron transfer reactions of pharmaceuticals with environmental surfaces under various chemical and physical conditions to get closer to real-world conditions. Furthermore, because various pharmaceutical compounds often coexist in contaminated systems, we also focus on assessing the molecular interactions of mixtures with surrounding environments and their transport in natural porous media. As these molecular mechanisms at mineral surfaces are not often considered in traditional thermodynamic modeling, we are developing new transport models that account for these new surface interactions and transformation kinetics in complex environmental mixtures. Our works consequently shows that reaction parameters controlling redox-active transport are needed to successfully describe changes in environments subject to variable water flow rates. Models accounting for these phenomena are crucial to our understanding of the transport and mobility of emerging contaminants in terrestrial and aquatic environments. The main problem related with the presence of antibiotics and their intermediate products in environmental systems is the possibility of inducing bacterial resistance genes. Failure to take into consideration redox mechanisms coupled to water flow in natural porous media may introduce a bias in the characterization of affected environments leading to misevaluation of ecotoxicity. Therefore, predicting mobility of parents and daughter compounds in groundwater and subsurface environments is crucial for assessing potential genotoxic effects and human health risks. To tackle this issue, we have recently started a collaboration with microbiologists to investigate the effect of antibiotics and their transformation products on the bacterial growth and denitrifying activity in natural systems.