Column- and catchment-scale transport of cadmium: effect of dissolved organic matter

摘要: Abstract In the Ellen catchment on Pinjarra Plain, NE of Perth in Western Australia, cadmium from fertilisers is starting to leach soils. About 70% surface soils are sandy and often top a shallow ephemeral water table. Adsorption Cd was studied by batch adsorption leaching small columns soil. increases linearly with increasing soil organic matter content exponentially pH. Cadmium significantly mobilised dissolved matter. The capacity most adsorb phosphate fertiliser has been saturated. Resulting concentrations Brook average ∼ 500 μg L −1 P. adsorbed more strongly than just into Brook. From comparison Cd/P ratios water, fertiliser, estimated be at 10–30% their maximum for complete breakthrough Present 0.1 approach 100 yr. Maximum could range 0.6 2 , depending rates input future agricultural land use catchment. Breakthrough curves, resulting through soil, indicate that effective hydrodynamic dispersion Cd. Longitudinal dispersivities, measured pore-water velocities 0.7–14 m day were 5 cm 0.1–0.2 chloride. much greater chloride shown not caused non-equilibrium adsorption.