Oceanological and Hydrobiological Studies International Journal of Oceanography and Hydrobiology Vol. XXXIII, No.2 Institute of Oceanography ISSN 1730-413X (77-93) 2004 University of Gdańsk eISSN 1897-3191 Copyright© by Institute of Oceanography, University of Gdańsk, Poland www.oandhs.org Water quality study of the Condor and Capivara Streams, Porto Alegre Municipal District, RS, Brazil, using epilithic diatom biocenoses as bioindicators a Eduardo A. Lobo 1,b , Vera Lúcia M. Callegaro 2,c , Carlos E. Wetzel 1 , Guilherme Hermany 3,d , Daniela Bes 1 1 Laboratory of Limnology, University of Santa Cruz do Sul (UNISC) Av. Independência, 2293 – Santa Cruz do Sul – RS - Brazil 2 Natural Sciences Museum, Zoobotanical Foundation of Rio Grande do Sul Av. Salvador França, 1427 – Porto Alegre – RS - Brazil 3 Graduate Course on Ecology, Federal University of Rio Grande do Sul Av. Bento Gonçalves, 9500, Campus do Vale – Porto Alegre – RS – Brazil Key words: water quality evaluation; urban streams; Porto Alegre, RS, Brazil; organic pollution; eutrophication; diatoms Abstract The aim of this work was to evaluate the water quality of two urban streams, Condor and Capivara, in the Municipal District of Porto Alegre, RS, Brazil, by measuring physical, chemical and biological variables. Between May 1999 and August 2000, six field trips were taken to sample five sites distributed along the streams. Multivariate canonical correspondence analysis (CCA) was applied for the complete evaluation of physical, chemical and biological data. It was confirmed that phosphate had the largest impact on ordination and exhibited an evident a Results of this paper were presented on an 5 th International Symposium “Use of Algae for Monitoring Rivers” Cracow, 2-6 September 2003, Poland b lobo@unisc.br c algas@fzb.br d guilherme.hermany@terra.com.br Original research paper