Total reflection X-ray fluorescence (TXRF) was used to evaluate the availability and contamination of inorganic elements in
sediment samples from Atibaia River, located at Piracicaba Basin, near the Campinas region, São Paulo State, Brazil. The total
contents (geological matrix) and the concentration of elements weakly linked to the sediment (available fraction) were determined.
The availability of these elements was evaluated through the ratios between available fractions and total contents. The results
showed that the elements Mn, Ni, Cu and Zn are easily available in the aquatic environment.