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Land use impacts on stream water quality in the Brazilian Cerrado

José Salomão Silva, UnB, (Presenting)
Daniel Markewitz, University of Georgia,
Mercedes Bustamante, UnB,
Roger Burke, Environmental Environmenta Protection Agency,

The Brazilian Cerrados are one of the main vegetable formations of the country, being second bigger national bioma. Some studies point that the quality of fluvial waters is influenced by the climate, geology, physiography, ground and biological activity in the basin. The Cerrados do not count on studies that show the geochemistry of surface water and ground waters. The goal of this work is to investigate the effect of the land use in the biogeochemistry and processes that occur in gallery forests. First-order streams had been selected in basins that drain natural, agricultural and urban areas in the adjacencies of the Brasilia City. During dry and rainy season water samples of streams had been collected for the determination of potassium, magnesium, calcium, sodium, ammonium, chloride, sulphate, nitrite and nitrate. The results had shown that the smaller average annual concentrations, in mg L-1, had been found in natural areas (K - 0,08 ± 0,13; Ca - 0,09 ± 0,11; Mg - 0,04 ± 0,02; Na - 0,14 ± 0,07; NO2 - 0,07 ± 0,05; NO3 - 0,12 ± 0,03 and NH4 - 0,05 ± 0,05). The urban areas had presented the bigger concentrations in this study (K - 0,54 ± 0,55; Ca - 1,03 ± 0,72; Mg - 0,25 ± 0,16; Na - 1,10 ± 0,65; NO2 - 0,20 ± 0,09; NO3 - 0,98 ± 0,78 and NH4 - 0.11 ± 0,15). The seasonality of the urban areas had not presented differences between the two seasons, except to NO2, which was bigger during the dry season. The agricultural areas had shown differences only for K, Mg and Ca, which had been bigger during the rainy season, whereas natural areas K, Ca, Cl and NO3 also had shown different between the stations, being K and Ca bigger in the dry season and the two last ones during the rainy season. The results show that the anthropic alterations had created a trend differentiation in the water quality of the studied streams, therefore the agricultural and urban areas were more enriched than the natural ones.

Science Theme:  LC (Land Use and Land Cover Change)

Presentation Type:  Poster

Abstract ID: 13

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