Avaliação da qualidade de sedimentos dos rios Tietê e Piracicaba nos seus compartimentos de entrada no reservatório de Barra Bonita, SP / Sediments quality evaluation of Tietê and Piracicaba rivers in the entrance compartments of Barra Bonita reservoirs




Along the last decades, Barra Bonita reservoir has been suffering with its water quality degradation, once its majors tributaries (Piracicaba and Tietê rivers) are inserted in high anthropic development regions. The monitoring of the water quality has suffered substancial changes, when considering the sediment as an integrator site of the processes ocurred in the water column and as a continued form of polution, since in some conditions there may be polutents and/or contaminents ressuspension. In this way, the work had as an objective the sediments qualitative evaluation of the major initial compartments (Piracicaba and Tietê rivers), under physical, chemical and biological aspects, considering the destination of the water public supply and the electrical energy production and these compartments insertion into the reservoirs ecosystem. Samples were colected along each tributary from the begining of the restraining area until the confluence region, and analysed the total and bioavailable metals, nutrients, organic matter, granulating metry, toxicant effect over test-organisms, public interest microrganisms density and recognization of the basin soils use and occupation, since 1960. It was found, that due to the reservoir implantation, intense changes in the urban scenery, resulting from rural exodus, with accelerated industrialization process in the reservoir influence regions. The results indicate river Tietê as being the most intensively affected by these activities, presenting high nutrients concentration, high density of fecal origem contaminators indicators, high polution by metals (Mn, Cd, Pb, Ni), being in the greater part of high mobility ones, so, weakly adhered to sediment particles, representing toxicity to the test-organisms used (Daphnia similis and Chironomus xanthus). This way, the sediments represent a continuous source of the system water quality degradation, causing damage to social, economical and enviromental orders.


sediments quality barra bonita reservoir rio piracicaba reservatório de barra bonita tietê river rio tietê qualidade de sedimentos piracicaba river

Documentos Relacionados