Bottom and suspended sediments characterization transported by the Guamium river, Piracicaba river basin, SP taking into account the sazonality.

Abstract

In the Guamium river basin, a branch of the Piracicaba river, which is at high deterioration degree due both to the lack of riparian zone, forested area surround and wrong land usage, it will be selected ecological units like bottom and suspended sediments, to demonstrate the disordered land development in a seasonal approch, during 01 year. The suspended matter will only be sampled at the final third part of the basin. Bottom sediment s will be sampled at 10 sample sites along the main river channel, at the dry period and wet one.Taking into account the landscape and soil usage, inorganic chemical species were selected to be investigated, such as Ca, Mg and K, which are the soils exchange bases, N and P the main nutrients for euthrofisation and C. C and N will be also evaluated regarding it total concentrations, in order to establish the C?N ratio, as good indication related to the anthropogenic influence on the biogeochemical cycles of both elements. In addition due the environmental importance of these elements, it will be determinated the isotopic abundance, determining the C13 and N15. In this sense it will be possible to asses for the different sources of the organic matter in the basin and the stage of mineralization of the organic matter. Samples will also be analysed for total As, considering the large use of arsenic herbicides employed in the sugar cane agriculture. All analytes will be analysed for total and bioavailable concentrations by using hot acid digestion and 1 mol/L HCl cold extraction respectively. Suspended matter will be sampled monthly, with exception at the rainy season in which sampling will follow each rain event, due to low water residence time in small basin, which could lead to mistakes in the river hydrographyc curves. In this situation a uncertain estimation should be achieved both for the total suspended material and to solid discharge of the chemical elements. River discharge will be calculated by using a current meter. The approch will be carried out at at every suspended mater sampling. It is also planned to evaluated the toxicity of sediments to planctonic organisms