Comparing the response of biochemical indicators (biomarkers) and biological indices to diagnose the ecological impact of an oil spillage in a Mediterranean river (NE Catalunya, Spain) Joana B. Dama ´sio a , Carlos Barata a, * , Antoni Munne ´ b , Antoni Ginebreda b , Helena Guasch c , Sergi Sabater c , Josep Caixach d , Cinta Porte e a Laboratorio de Toxicologı ´ a Ambiental, UPC, CN150 Km 14.5, Terrassa 08220, Spain b Agencia Catalana de l’Aigua, c/Provenc ¸a, 204-208, Barcelona 08036, Spain c Institute of Aquatic Ecology, University of Girona, Campus Montilivi, 17071 Girona, Spain d Departament d’Ecotecnologies, IIQAB-CSIC, Jordi Girona 18, Barcelona 08034, Spain e Department of Environmental Chemistry, IIQAB-CSIC, Jordi Girona 18, Barcelona 08034, Spain Received 3 April 2006; received in revised form 10 July 2006; accepted 14 July 2006 Available online 7 September 2006 Abstract Three biomarkers of hydrocarbon exposure, liver 7-ethoxyresourfin-O-deethylase activity (EROD), fluorescent hydrocarbon com- pounds (FACs) in bilis, and the liver antioxidant enzyme catalase (CAT) were examined in the autochthonous fish species Barbus merid- ionalis collected in the river Fluvia ` (NE Catalunya, Spain) after an oil spillage. Four different locations were sampled, including the impacted site, upstream and downstream sites and a reference site. Biomarker responses were compared with diatom and macroinverte- brate community assemblage metrics (Specific Pollution Sensitivity index – IPS, and Iberian Biological Monitoring Working Party – IBMWP, respectively). Chemical analyses denoted that polycyclic aromatic hydrocarbon levels in sediment were much higher at the impacted site than in downstream reaches. Four fold increase of EROD activity together with increased levels of biliary FACs in barbs collected at the spilled site indicated exposure of inhabiting fish to the oil. Additionally, CAT activity was significantly depressed (four fold) when compared to other stations, thus suggesting that fish collected from the impacted sites could be more susceptible to suffer oxidative stress. Biological indices (particularly that of the diatom community IPS) showed slight significant effects between control and impacted sites, indicating that more tolerant taxa were favoured because of the oil spillage. These results support the need to include biochemical responses measured in local species in monitoring programmes aimed to diagnose specific pollution effects in stressed river ecosystems. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Mediterranean river; Biomarkers; Biological indicators; Water Framework Directive; Oil spill 1. Introduction Chemical and ecological assessment of water quality is fundamental to the management of surface waters and the protection of aquatic ecosystems. Chemical quality of the aquatic media is largely based on the presence of so called organic micropollutants. Due to the great variety of the potential compounds available, their control is based on the specific surveillance of certain groups or ‘‘priority lists’’ of substances that only include a limited number of com- pounds. Furthermore, because their different physico-chem- ical properties, an adequate control requires monitoring of the ‘‘environmental compartments’’ involved, i.e., water, sediments and biota. Due to those drawbacks, the chemical approach, while still valid, is expensive and cumbersome, and thus, other indicators showing more integration capac- ity are desirable. Traditionally, in Europe and other indus- trialized regions, biomonitoring of fresh waters has been based on measures of community structure, focussing on 0045-6535/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2006.07.055 * Corresponding author. Tel.: +34 93 7398396; fax: +34 93 7398392. E-mail address: barata@intexter.upc.edu (C. Barata). www.elsevier.com/locate/chemosphere Chemosphere 66 (2007) 1206–1216