An experiment was carried out to evaluate the effects of the application of urban waste compost on production and contents of heavy metals in lettuce and different soils in pots of 9 dm³. The experimental treatments resulted from a 3 x 4 factorial arrangement of a Red Yellow Latosol (sandy clay loam), a Red Yellow Latosol (loamy sand) and a Quartzarenic Neosol (sandy loam) combined with the urban waste compost doses of 0, 30, 60 and 90 t ha-1, on dry weight basis. The experimental design was a randomized complete block with 3 replicates. Soil pH, fresh and dry matter weight and Zn, Cu, Cd, Pb and Ni concentrations were determined in the soil and the leaf tissue. The application levels of urban waste compost increased dry and fresh matter of lettuce and the heavy metal concentrations in the soil. In plant, the levels of Zn in clay soil and of Cu, increased with increasing doses of waste compost, while the Zn and Cd in sandy soil decreased with increasing doses of this waste. The Pb levels in leaf tissue surpassed the phytotoxic level recommended for the human and animal consumption. The Zn and Cd elements showed low and high leaching percentage respectively.
Lactuca sativa L.; organic waste; soil pollution
