Elemental content of vegetables and apple trees grown on syracuse sludge-amended soils

Two successive crops of peppers, kohlrabi, lettuce, peas, spinach, sweet potatoes, and turnips were grown in pots of control and municipal sludge-amended acid and neutral soils. Two commercial apple cultivars were also cultured. Cadmium, copper, nickel, and zinc were higher in the sludge-grown crops. Cadmium, nickel, and zinc were usually higher in vegetable crops grown on the sludge-fortified acid soil. Copper was higher in the vegetables grown on the neutral soil-sludge mixture. Nickel and zinc generally decreased in concentration in sludge-grown vegetable crops and apple trees during the second year of growth. There was not a consistent varietal or soil pH effect as regards heavy metals in apple trees. Copper and zinc tended to concentrate in apple twigs while nickel and lead concentrated in apple leaves. Metal residues in apple fruit were comparatively low.