O uso de fosfatos associado à fitorremediação em solos de Santo Amaro (BA) contaminados por metais tóxicos

• Autor(a) principal: Kede, Maria Luiza Félix Marques
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/14293
• topic: Toxic metals; Remediation; Phosphates; Phytoremediation; Bioavailability; Metais tóxicos; Remediação; Fosfatos; Fitorremediação; Biodisponibilidade; Solos - Remediação; Solos - Poluição; Fitorremediação; CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIA::GEOQUIMICA

The soil contamination by toxic metals in Santo Amaro municipality (BA) by the industry Plumbum Mining has caused impacts on the environment and human health, as well as economic and social impacts due to the high levels of lead (Pb) and cadmium (Cd) in the air, soil and water. The aim of this research was to access the feasibility of remediating this soil using different sources of phosphates associated to the phytoremediation by vetiver grass [Vetiveria zizanioides (L.)]. Soil samples were treated in PVC columns with the application of dihydrogen potassium phosphate (KH2PO4) (T1), reactive natural phosphate fertilizer (RNP) (T2) and a mixture of KH2PO4 and RNP fertilizer (T3). Untreated contaminated soil samples (T0) were used as control. Soil samples were taken from the columns for analysis after 60, 120 and 180 days of treatment. At the end of each time period, vetiver grass [(Vetiveria zizanioides (L.)] was planted in pots in triplicate with soil taken from the columns T0, T1, T2 and T3. To determine the concentration of Pb and Cd an ICP - OES was used. Based on the physical and chemical analyzes was found that the soil has clayey and high cation exchange capacity (CEC) that are found in Vertisols. Extractions with DTPA and TCLP showed that the most effective treatment to immobilize Pb and Cd was T1 followed by T3, however, exceeded the regulatory limit established by the USEPA and is therefore considered toxic. In the sequencial extractions with BCR method after remediation and phytoremediation has been verified that all three treatments were effective in restraining Pb and Cd in the less soluble forms, however, the Cd is more soluble and has higher mobility than the Pb. Lethality tests using earthworms Eisenia andrei showed mortality was higher in the treatments 60 days, reducing registration of deaths at 120 and 180 days. The loss of biomass was reduced according to the treatment time. The germination tests with lettuce (Lactuca sativa L.) indicated that samples of treated soil still was toxic, although they have reduced the availability of Pb and Cd as seen in the results of the TCLP and BCR. The ecological potential risk assessment indicated that the treatment of the soil with phosphates and more phytoremediation reduced mobility of Pb, especially for T1 and T3. For Cd the ecological potential risk considerably increased compared with the element Pb demonstrating that despite therapy with phytoremediation more phosphates remains quite soluble. KH2PO4 Treatment with (T1) was the most effective in reducing mobility, availability and toxicity the metals followed by T3 and T2 to Pb and T3 followed by T1 and T3 to Cd.