ABSTRACT
The effects of long-term application of sewage sludge (i.e., at least 10 years in duration) on metal distribution in the soil profile, the response of crop yields, and the bioavailability of metals were reviewed using results from field trials mostly located in the European Community and the U.S. In almost all of the studies, sludge-borne metals appeared to remain in the zone of sludge incorpo ration (e.g., 0-15 cm depth). The metal recoveries resulting from mass balances of metals added into the soil ranged from 30 to 90%. Lateral soil movement was the main explanation of the progressive “disappearence” of metals from experi mental plots.
