Dual-continuum analysis of a cadmium tracer field experiment

Cadmium penetration into a sandy–loam soil during the field ponded infiltration at Kralovska luka site in Southern Slovakia was observed in a controlled experiment. Adsorption of cadmium was examined using the radioactive tracer techniques in laboratory batch tests. Quite deep 115mCd penetration during the field experiment (65 cm beneath the soil surface) gives evidence of the particle-facilitated transport of cadmium through preferential pathways. More than 40% of the applied cadmium moved deeper than 10 cm. The field experiment was analyzed using both conventional single-continuum approach (based on Richards' equation for water flow and advection–dispersion equation for Cd transport) and dual-continuum approach. The latter approach allowed us to simulate more adequately the observed movement of cadmium.