INTRODUCTION

1. 2011 SSSA-CSSA-ASA Annual Meetings - Oct. 16-19, 2011 San Antonio, TX. HEAVY METAL CONCENTRATION IN A DEGRADED SOIL AFTER SEWAGE SLUDGE APPLICATION. IRAÊ AMARAL GUERRINI(1); THALITA FERNANDA SAMPAIO; JULIO CESAR BOGIANI; CLARICE BACKES; NAYARA CRISTINA DE CARVALHO. (1)Universidade Estadual Paulista/UNESP, Campus de Botucatu - SP, CEP: 18610-307, iguerrini@fca.unesp.br RESULTS E DISCUSSION INTRODUCTION The recovery time of degraded areas is slow and related to the physical, chemical and biological restoration of soil capacity. The application of organic materials, such as sewage sludge, improves such capacity in the long term, and this practice decreases the use of mineral fertilizers and contributes to save energy and natural resources. Despite the benefits of sewage sludge application to soils, the presence of several pollutants in sludge, such as heavy metals and pathogenic organisms, become a problem to people and environment. OBJETIVES The objective of this study was to assess possible contamination by heavy metals in a degraded area of sandy soil after application of increasing doses of sewage sludge in order to recover it. FIGURE 1. Total teor of Cd and Hg in the soil 6 months after sludge application. FIGURE 2. Total teor of Cd e Hg in the soil 12 months after sludge application. MATERIALS E METHODS The experiment was conducted at “Entre Rios” Farm from Suzano Bahia Sul Company, in Itatinga, São Paulo State, Brazil. The treatments were: doses of sewage sludge on a dry basis (2.5, 5, 10, 15 and 20 Mg ha-1 + K supplementation), conventional fertilization (NPK) and control. Nine species of the Atlantic Forest were tested: Croton floribundus, Schinus terebinthifolius, Peltophorum dubium, Cedrella fissilis, Guazuma ulmifolia, Anadenanthera macrocarpa, Copaifera langsdorffii, Hymenaea courbaril and Cariniana estrellensis. Figure 3 shows the methodology of soil preparation and sludge application. CONCLUSIONS Higher doses of sludge increased the total and available heavy metals in soil. However, until the dose of 20 Mg ha-1, the presence of metals was not detected in foliar analysis carried out up to 18 months after sludge application. The levels of heavy metals available in the soil remained below the limit allowed by Brazilian and international laws. Figura 3.Soil preparation and sludge application. ACKNOWLEDGEMENTS: