The geochemical behavior of natural radionuclides in coastal waters: A modeling study for the Huelva estuary

► Transport of metals simulated in a tidal estuary affected by AMD. ► Model simulates hydrodynamics, uptake/release reactions between water and sediments. ► Effects of pH and salinity on kinetic coefficients included. ► Computed metal concentrations compared with measurements in 4 seasonal campaigns. ► Sensitivity tests to study the effects of water circulation and metal sources.