Sewage sludge has a great potential for agricultural use, however, this form of disposal is of concern since there is possibility of heavy metals insertion in food chain. The objective of this study was to evaluate the contents of heavy metals in soil and sunflower plant in response to fertilization with sewage sludge under different stabilization processes. The experiment was conducted in Haplic Cambisol, with the treatments: control (without fertilization), fertilization with solarized sewage sludge, fertilization with composted sewage sludge, fertilization with vermicomposted sewage sludge, fertilization with limed sewage sludge and chemical fertilizer recommended for the crop. A randomized block design with four repetitions was used. Independent of stabilization method, the application of sewage sludge did not affect the Cu, Cr, Cd and Ni concentrations in the soil, but increased Zn levels. Also, the application of solarized sewage sludge and of the limed sewage sludge increased Pb content in soil. In general the contents of heavy metals in sunflower leaf and petiole were not influenced by sewage sludge application.
Helianthus annuus; biosolids; composting; vermicomposting; limed sludge
