Arsenic (As) is an abundant metal in the earth's crust, occurring in various environmental compartments, as well it can be available by anthropogenic activities. In the last years, high concentrations of arsenic (up to 4 mg L-1) were detected in saline-alkaline lakes from Nhecolândia, located in Pantanal wetlands. This region is characterized by a rich biodiversity, and by the occurrence of many lakes with very specific characteristics, such as high pH (8 - 11) and salinity. Moreover, saline-alkaline lakes occur along with freshwater lakes. The biogeochemical cycle of As, as well its bioavailability and speciation, are poorly known in this region. Thus, this work aims to contribute on the knowledge of the environmental behavior of arsenic in alkaline-saline lakes from Nhecolândia, since one of the main objectives is to evaluate de bioavailability and speciation in the sediment/water interface (SWI) where relatively low concentrations (up to 20 mg / kg) have already been determined, unlike in the water column and subsurface waters around lagoons, where As concentrations can reach up to ~ 4 mg/L. The use of the passive sampling technique Diffusive Gradients in Thin Films (DGT) is a central point in this work. Applying this passive sampler aims to minimize problems associated to the sampling, as well as giving valuable information regarding bioavailability, mobility and fluxes of arsenic in sediment/water interface, among others potentialities that will be explored. Moreover, other features of DGT sampler would be explored during the sandwich period in the Prof. Paul N. Williams's laboratory at Queen's University (Irlande). Therefore, at the end of this work, a reliable status of contamination, mobility and bioavailability of arsenic in the sediment/water interface of saline-alkaline lakes from Nhecolândia is expected.
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