Trace-Elements Concentration in Soils from Wetlands in the Brazilian Savanna Biome.

Trace-elements like As, Cd and Pb depending on their concentration and bioavailability may be dangerous for plant, animal and human health. These elements can be introduced into the soil due to human activities. From 1970’s, the Savanna Biome in Brazil has been gradually converted to areas for crop production. In this biome is common the occurrence of wetlands, called in Brazil as “Veredas”, surround by intense agricultural activities. The wetlands play an important environmental function in Brazilian Savanna, mainly as spring. Six wetlands located in Uberlândia region, Minas Gerais State, Brazil, were selected for evaluate the concentration of Cd, Pb, As, Zn and also Fe (major element). In each wetland were collected topsoil samples (0-20 cm depth), distanced each other in ~ 50 m at different positions in the wetland: upper, middle and lower. The soil samples were air-dried, ground and sieved. After that, the soil digestion procedure was performed according to USEPA 3051A protocol, and determination by FAAS. The Cd, Pb, As and Zn concentrations are below the threshold values established by Brazilian guidelines. Except for As, the elements concentration increased from the upper to lower position in the wetland, suggesting the movement at the soil surface by runoff and accumulation in organic rich topsoil (lowest position in the wetland). Acknowledgments: CNPq (475922/2013-01), CAPES and FAPEMIG.