Einfluss von Tonmineralen und Fe-Oxiden auf die Mobilität von Schwermetallen und deren Aufnahme durch Weizen

The capacity of some additives to soil originated from sewage sludge to fix Cd, Zn, and Cu, was evaluated using a pot experiment. Following substances were applied: two natural clay minerals (Na-bentonite and zeolite) at 1% and 2%, and iron oxide (goethite) at 1%. Metal content of wheat shoots and heavy metals available in the soil were determined after 45 days. The largest effects to reduce the mobility and phytoavailability of heavy metals occurred after addition of Na-bentonite at 2%. Compared to the untreated soil, the mobility of all heavy metals was significandy reduced by 36% and 16% for Cd, by 25% and 9% for Zn, and by 33% and 14% for Cu using Na-bentonite and zeolite at 2%, respectively. However, the addition of goethite reduced significandy the mobility of Zn and Cu by 9% and 7%, respectively. The highest reduction in shoot uptake of all heavy metals was occurred after addition of Na-bentonite at 2%. Among tested additives, Na-bentonite exhibited a most promising potential to reduce bioavailability of Cd, Zn and Cu to wheat plant.