Aspects of anthropogenic influence in Piracicaba (SP) river dissolved load

The anthropogenic influence in Piracicaba river dissolved load were studied for major inorganic chemical species and characterized in terms of total loads. The concentration distribution curves, in function of time, were compared with respective theoretical dilution, what allowed the identification of punctual and diffuse contributions in the drainage basin. The dissolved chemical loads transported in these surface waters were calculated by stochastic method, and they were more significant for HCO3-, Na+and SO42-. Nitrogen species (NH4+ and NO3-) were the most significant rainwater contribution. The punctual contributions were mainly associated to raw urban sewage released without treatment, considering Na+, Cl-, PO43-, SO42- and part of HCO3- species. The diffuse contributions were related to rainwater, soil cultivation and rocks weathering contributions.