Evaluation of waterborne exposure to oil spill 5 years after an accident in Southern Brazil $ C.A. Silva a , C.A. Oliveira Ribeiro b , A. Katsumiti b , M.L.P. Arau ´ jo b , E.M. Zandona ´ c , G.P. Costa Silva c , J. Maschio b , H. Roche d , H.C. Silva de Assis c, a Programa de Po ´s-Graduac - a ˜o em Ecologia e Conservac - a ˜o, Caixa Postal 19031, CEP 81531-970, Curitiba-PR, Brazil b Departamento de Biologia Celular, Caixa Postal 19031, CEP 81531-970, Curitiba-PR, Brazil c Departamento de Farmacologia, Universidade Federal do Parana ´, Caixa Postal 19031, CEP 81531-970, Curitiba-PR, Brazil d Universite´ Paris-Sud XI, ESE UMR 8079 Ecologie Syste´matique et Evolution, Ba ˆtiment 362 F91405 Orsay Cedex, France article info Article history: Received 9 June 2007 Received in revised form 17 March 2008 Accepted 23 March 2008 Available online 13 May 2008 Keywords: Oil spill Biomarkers Astyanax sp. Bile Bioassay abstract Fish (Astyanax sp.) were exposed to water samples from the Arroio Saldanha, locality of an oil spill, and the Barigui River (upstream and downstream of the confluence of the river and Arroio Saldanha), Brazil. Histopathological and biochemical biomarkers, as acetylcholinesterase (AchE), ethoxyresorufin-O- deethylase (EROD), catalase (CAT), glutathione-S-transferase (GST) activities, lipid peroxidation (LPO) levels, and amounts of polynuclear aromatic hydrocarbon residues (PAHs) in bile were evaluated. PAHs, metals, and surfactants were investigated in the water samples. CAT and GST activities increased in the Arroio Saldanha sample, whereas CAT activity and LPO levels were increased in the upstream and downstream sites. The results suggested a toxic action of the free radicals and disturbance of the antioxidant defense mechanisms. However, the EROD and AchE activities were not affected. Histopathology studies showed severe lesions. The oil is still bioavailable to biota, moreover, other pollution sources continue to affect the water in the Barigui River. & 2008 Elsevier Inc. All rights reserved. 1. Introduction Due to human urban and industrial activities, rivers are dumped with different kinds of chemicals such as polynuclear aromatic hydrocarbons (PAHs), affecting the inhabiting aquatic organisms individually and thereby potentially harming the ecosystem. Environmental accidents, such as oil spills, aggravate this problem, and biomonitoring studies associated with new methods to evaluate the detrimental effects on biota have been increasing in number over the past few decades. The pollution resulting from the release of oil into the aquatic environment due to recent accidents has become a global concern because of its effects on aquatic ecosystems. The accident in the Arroio Saldanha stream in 2000 caused the spillage of approximately 4 million liters of oil from the PETROBRAS Refinery (REPAR), located in the Parana ´ State of Southern Brazil; this accident, due to a scraper rupture, affected an area of 2.5 km 2 that included many small streams plus the important Barigui and Iguac - u rivers; the affected region within the rivers extended to an approximately 50-km- wide expanse. In general, crude oil constitutes 75% of liposoluble hydro- carbons, most of which possess potential carcinogenic properties (Neff, 1978; Brauner et al., 1999; Pedrozo et al., 2002). The biomarkers, which have been used by various researchers (Walker et al., 1996; Regoli et al., 2005; Rocher et al., 2006), showed measurable response at all levels of biological organization and have been used as important tools to evaluate the exposure to environmental pollutants. In biomonitoring programs, histo- pathological findings, when analyzed together with biochemical endpoints, facilitate the observation of the physiological response in individuals, thereby establishing a more realistic diagnosis for evaluating environmental health (Akaishi et al., 2004). The induction of cytochrome P450 (CYP 450) has been used to assess the effects of petroleum, crude oil, or harmful metabolites on various aquatic organisms, especially fishes, which have shown a sensible biological response to PAHs (Rocher et al., 2006). The induction mechanism begins with the stimulation of the tran- scription of the CYP1A gene, resulting in the specific increase of ARTICLE IN PRESS Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/ecoenv Ecotoxicology and Environmental Safety 0147-6513/$ - see front matter & 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.ecoenv.2008.03.009 $ This research was partially supported by the Brazilian government (CNPq). The Parana ´ Environmental Institute (IAP) provided support for the chemical analysis of water.All the procedures of this study were carried out in accordance with the Guide for the Care and Use of Laboratory Animals (Canadian Council on Animal Care) and the animal protocol approved by Parana ´ Federal University’s ethical committee for animal experimentation. Corresponding author at: Departamento de Farmacologia, Universidade Federal do Parana ´, C.P.19031, CEP: 81.531-990, Curitiba – PR, Brazil. Fax: +55 413266 2042. E-mail address: helassis@ufpr.br (H.C. Silva de Assis). Ecotoxicology and Environmental Safety 72 (2009) 400– 409