[6] From 1982 to 1988, Santschi served as the head of the Isotope Geochemistry and Radiology Section at the Swiss Federal Institute of Aquatic Science and Technology (EAWAG).
[7] Santschi's research interests span Environmental Chemistry, Biogeochemistry, and Radiochemistry, with emphasis on the role of colloidally sized macromolecular organic matter, especially microbially derived Exopolymeric Substances (EPS).
The study found that early diagenetic transformations driven by organic carbon and electron acceptors significantly influence elemental cycling and fluxes, with physical transport mechanisms and three-dimensional interactions playing crucial roles.
[13] Furthermore, his collaborative 1998[14] and 2004 studies revealed that polymer gel particles, showed recent radiocarbon ages for carbohydrate enriched fractions, were abundant and crucial in marine ecosystems, significantly impacting carbon cycling sedimentation, and microbial habitats, and highlighted the need for further interdisciplinary research to understand their roles and dynamics.
[15] Moreover, through his 2008 research, in collaboration with W.C. Chin, he examined the environmental impact of engineered nanoparticles (ENPs), finding that their surface properties, interactions with organic matter, and effects on biological cell walls significantly influence their behavior, bioavailability, uptake, and toxicity in algae, plants, and fungi.
[18] More recently, he documented the widespread observation that when algae and bacteria are exposed to pollutants, in particular nanoparticles such as nano- and microplastics, they respond with secreting more hydrophobic and protein-rich EPS.
The study found significantly higher uranium concentrations in the rhizosphere, attributed to enhanced binding with reactive iron (III) oxides formed by plant roots.