Cadmium Uptake for Swiss Chard Grown on Composted Sewage Sludge Treated Field Plots: Plateau or Time Bomb?

Two hypotheses have been proposed to describe the phytoavailability of potentially toxic metals in sewage sludge treated soils. The plateau theory argues that the metal adsorption capacity added with sludge will persist as long as the metals of concern persist in the soil and the metals would remain in chemical forms not readily available for plant uptake. Therefore, the metal concentrations of plant tissue will reach a plateau as sewage sludge...