“…(Keswick et al, 1982, Becker et al 2003 Microspheres / nanoparticles) Aq. Hydraulic connection, groundwater drift, mixing None, (adsorption, coagulation, size exclusion) Fluorescently labeled polystyrene or latex microspheres (Becker et al, 1999;2003), artificial DNA labeled microspheres (Sharma et al, 2012), fluorescent silica nanobeads (Agenet et al, 2011) Partitioning tracers (equilibrium tracers) Cation exchange, (anion exchange) Inorganic (Dean et al, 2012) and organic cations (bases) (Leecaster et al, 2012;Reimus et al, 2012) Ionic molecules, low log D, high pKa…”