Preface: Special section on emerging particles and biocolloids in terrestrial and aquatic systemsPreface: Special section on emerging particles and biocolloids in terrestrial and aquatic systems Εισαγωγή Επιμελητή Editorial 2024-02-272023enEmerging contaminants such as engineered nanoparticles and microplastics, as well as colloids and biocolloids, enter subsurface environments after accidental or intentional release. Once released, these particles represent another mobile solid phase in the subsurface. Colloid transport is substantially different than solute transport. Furthermore, transport of nanoparticles and microplastic in porous media differs substantially from conventional colloid and biocolloid transport, because the transport properties of these particles change more significantly due to aggregation (homo- and heteroaggregation) and interactions with dissolved substances in soil. The formation of larger particles with different physical and chemical characteristics or the breakdown of larger particles due to biodegradation are visible changes. Although the fate and transport of emerging particulate contaminants have been examined extensively in the past few years, their behavior in the subsurface is not fully understood. This special section was motivated by a series of interdisciplinary sessions entitled “Emerging particles and biocolloids in terrestrial and aquatic systems,” organized by the guest editors at the European Geosciences Union Annual Meeting in Vienna, Austria.http://creativecommons.org/licenses/by-nc-nd/4.0/Vadose Zone Journal221Chrysikopoulos_et_al_Vadose Zone J._22(1)_2023 p.pdfChania [Greece]Library of TUC2024-02-27application/pdf139.1 kBfree Chrysikopoulos Constantinos Χρυσικοπουλος Κωνσταντινος Baumann Thomas Tong Meiping Darnault Christophe Wiley Engineered nanoparticles Microplastics Colloids Biocolloids