Cadmium phytoavailability in soils and evaluation of extractant effectiveness using an isotope technique

Autor(es)

Guerra, Fernando ; Trevizam, Anderson Ricardo ; Fior, Rafael Carvalho ; Muraoka, Takashi

• Tipo de documento: Artigo Científico
• Fonte: CIENTIA AGRICOL; v. 71, n. 5, p. 6-pg., 2014-09-01.

Resumo

Large areas of land are nowadays contaminated by heavy metals and, it is therefore, important to monitor their levels in soils. Vegetables act as transfer mechanisms of such contaminants from soils to higher levels in the food chain. In this study, we aimed to evaluate the effectiveness of chemical extractants by the L-value method for Cd phytoavailability using the Cd-109 radionuclide. In a greenhouse experiment, rocket plants (Eruca sativa L.) were cultivated in pots with samples from Typic Hapludox and Typic Quartzipsamment soils. Cadmium concentrations ranging from 0 to 16 mg kg(-1) were added to a 200 mL solution containing 148 kBq Cd-109. The available Cd in the soil was extracted by DTPA, Mehlich-1, Mehlich-3, and a mixture of organic acids (acetic, citric, lactic, and oxalic acids). Cd concentrations were determined by atomic absorption spectrophotometry, and Cd-109 radionuclide activity was measured by low-level beta-counting. The dry matter yield was not influenced by Cd rates, but the Cd content and accumulation in shoots had a positive linear correlation. Generally, Cd was extracted in higher quantities by Mehlich-1 followed by DTPA, Mehlich-3, and organic acids. A linear correlation was found between the chemical extractants and Cd accumulation in shoots for both soils. According to the L Ratio, the extractants based on strong acids and chelating agents presented low efficiency regarding Cd phytoavailability. The organic acids, which presented values close to the L-value, may provide a promising method for evaluating environmental contaminants. (AU)

• Processo FAPESP: 09/03777-0 - Cádmio na cadeia alimentar: proveniente de vegetais e avaliação da sua disponibilidade no solo com auxílio do 109Cd
• Beneficiário: Fernando Guerra
• Modalidade de apoio: Bolsas no Brasil - Mestrado