Uses of As, Ba, B, Cd, Cr, Co, Cu, Bp, Mn, Hg, Mo, Ni, Se, Ag, Sn, V, and Zn are reviewed. Total concentrations of trace elements in sewage sludges vary videly. Ranges are reported for sludges from approximately 300 treatment plants from different regions in the U.S.A., Canada, Sweden, England, and Wales. No apparent relationship exists between the total concentration of trace elements in sludge and the amount dissolved by organic acids or water. Field and greenhouse studies have demonstrated that yields and trace element concentrations of higher plants grown on sludge-amended soils are dependent upon the amount of sludge applied, trace element composition of the sludge, soil pH, and plant species.