Monitoring water quality in reservoirs for human supply through multi-biomarker evaluation in tropical fish Izabella de Andrade Brito, a Carolina Arruda Freire, b Fl avia Yoshie Yamamoto, a Helena Cristina Silva de Assis, c Luciana Rodrigues Souza-Bastos, b Marta Margarete Cestari, d N edia de Castilhos Ghisi, d Viviane Prodocimo, b Francisco Filipak Neto a and Ciro Alberto de Oliveira Ribeiro * a Received 10th June 2011, Accepted 21st November 2011 DOI: 10.1039/c2em10461j Para  ıba do Sul River is located at a very densely inhabited region of Brazil crossing the three most industrialized states of the country (Sa ˜o Paulo, Minas Gerais and Rio de Janeiro states). As a result, industrial and farming residues as well as urban sewage are frequently disposed without appropriate treatment. The current study aimed at investigating the water quality in three reservoirs along the Para  ıba do Sul River (Ilha dos Pombos, Santa Cec  ılia and Santa Branca), through physiological, morphological, biochemical, and genetic biomarkers. The bioindicator chosen was the catfish Pimelodus maculatus, sampled during the dry (June 2008) and rainy (February 2009) seasons. Also, some water physicochemical parameters were analyzed from the sampling sites, but displayed no alterations according to the Brazilian Agency for Water Quality Legislation. Branchial carbonic anhydrase activity was inhibited in the dry season, while renal carbonic anhydrase activity was inhibited in the rainy season in the Santa Branca reservoir, indicating disturbance of osmoregulatory and acid–base regulation processes. Histopathological alterations were observed in the gills (neoplasic and tissue hyperplasia processes) and liver (necrosis), indicating serious damage to the functional integrity of these organs. A high incidence of melanomacrophage centers was observed in the liver, suggesting an intense immune response in all reservoirs. Acetylcholinesterase and catalase activity showed also differences corroborating some morphological results. Likewise, the induction of the micronucleus and DNA damage indicate genotoxicity, but mainly in the Santa Branca reservoir. Thus, the health status of P. maculatus warrants caution in the use of the water from the 3 reservoirs for direct human consumption, particularly after the accidental spill of endosulfan in November 2008, three months before the rainy season sampling. Introduction Brazil has an extensive fluvial system corresponding to approxi- mately 18% of the available surface freshwater in the planet, and 90% of these areas are located in regions of low population density. 1 However, the highest urban concentration is in the south- eastern and southern regions of the country, which leads to serious environmental problems and restriction of access to potable water. 2 Para ıba do Sul basin is located in one of the most populated and developed areas of Brazil, where there are potential conflicts regarding the use of water resources. The high human occupation a Departamento de Biologia Celular, Universidade Federal do Paran a—Setor de Ci^ encias Biol  ogicas, Centro Polit ecnico, PO Box 19031, Curitiba, PR, Brazil 81531990. E-mail: ciro@ufpr.br; Fax: +55- 41-3361-1756 b Departamento de Fisiologia, Setor de Ci^ encias Biol  ogicas, Universidade Federal do Paran a, Caixa Postal 19031, CEP 81531-970 Curitiba, PR, Brazil c Departamento de Farmacologia, Setor de Ci ^ encias Biol  ogicas, Universidade Federal do Paran a, Caixa Postal 19031, CEP 81531-970 Curitiba, PR, Brazil d Departamento de Gen etica, Setor de Ci^ encias Biol  ogicas, Universidade Federal do Paran a, Caixa Postal 19031, CEP 81531-970 Curitiba, PR, Brazil Environmental impact The current study is the first one developed in these reservoirs using multi-parameter biomarkers to evaluate the water quality. The results showed an impact of human activities in all studied sites, including the drastic situation in the Santa Cec  ılia reservoir from the Rio de Janeiro City (10 million people) that depends on it for water supply. The results represent strong data for the establishment of politics of water quality control and a basis of arguments to develop new studies. The scientific divulgation of the present data is imperative to show the relevance of this study in water management politics. This journal is ª The Royal Society of Chemistry 2012 J. Environ. Monit., 2012, 14, 615–625 | 615 Dynamic Article Links C < Journal of Environmental Monitoring Cite this: J. Environ. Monit., 2012, 14, 615 www.rsc.org/jem PAPER