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| Author(s): |
Maria Julia de Lima Brossi
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Centro de Energia Nuclear na Agricultura (CENA/STB) |
| Defense date: | 2008-08-29 |
| Examining board members: |
Cassio Hamilton Abreu Junior;
Cassiana Maria Reganhan Coneglian;
Maria Emilia Mattiazzo Prezotto
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| Advisor: | Cassio Hamilton Abreu Junior |
| Abstract | |
The application of sewage sludge in forest systems quests the improvement of the production, favoring the physical, chemistries and biological characteristics of the soil and of the plants. However, the sludge can contain pathogen and, organic and inorganic toxics elements, and the effect of these pollutants in the soil and in the plant is still unknown. It was established the hypothesis that the sewage sludge, when applied to the soil, according to the norm P4.230 of CETESB, doesn\'t cause toxics effects to the soil-eucalyptus system. To test the hypothesis above, it was established as objective, the determination of the concentration of the potentially toxics elements, the evaluation of the toxicity and genotoxicity of the sewage sludge treated soil, and the verification of the correlation among those variables. The field experiment was conducted in December of 2004, when seedlings of Eucalyptus grandis were planted and treated with sewage sludge, in the doses of 0; 7,7; 15,4 and 23,1 tha 1, dry base, in commercial area of eucalyptus cultivation of the Suzano Bahia Sul Papel and Celulose S.A company, in Itatinga, SP. Soil samples were collected to the 18, 21, 24, 27 and 34 months after the application of the sludge. They were established the concentrations of Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb in the soil, extracted for DTPA, Mehlich-1 and with concentrated HNO3+HCl, and quantified by ICP-MS. The toxicity of the soil was evaluated through the tests with D. magna (lethal concentration -LC50), with Pseudokcrichirella subcaptata (growth inhibition - IC50), with Lactuca sativa (root growth) and with Allium cepa (mitotic index, cromossomic aberration and micronucleus). The results showed an increase in the concentrations of Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb in the soil in agreement with the doses. An increase of the toxicity was observed for D. magna, P. subcaptata and an increase of the genotoxicity and mutagenicity for A. cepa in agreement with the doses. The applied sewage sludge to the soil in the dose of 15,1t ha-1, recommended by CETESB, doesn\'t cause toxic, genotoxic or mutagenic effect in the system soilplant, in agreement with the accomplished tests. There is correlation among the toxicity tests with P. subcaptata, of mutagenicity with A. cepa (micronucleus) with the concentrations of Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb in the soil. The test with D. magna is an important tool in the toxicological evaluation of the sludge applied to the soil, however it wasnt correlated with the concentration of potentially toxics elements in the soil, indicating that the toxicity of the sludge can also be related to the other toxic organic compound or pathogen agents. The L.sativa toxicity test is inadequate in the toxicological evaluation of the sludge application, according to the doses, for reflecting effects of the nutrients and it doesnt reflect the toxic components of the sludge, however it reflects the toxicity in agreement with the time of residue application (AU) | |