Pollution biomarkers in two estuarine invertebrates, Nereis diversicolor and Scrobicularia plana, from a Marsh ecosystem in SW Spain Montserrat Solé a,b, ⁎, Justyna Kopecka-Pilarczyk c,d , Julián Blasco a a Instituto de Ciencias Marinas de Andalucía (CSIC), Av. República Saharaui,11510 Puerto Real, Cádiz, Spain b Institut de Ciencies del Mar (CSIC), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain c Polish Academy of Sciences, Institute of Oceanology, ul. Powstańców Warszawy 55, 81-712 Sopot, Poland d Centro Interdisciplinar de Investigaçăo Marinha e Ambiental (CIIMAR), Rua dos Bragas 289, 4050-123 Porto, Portugal abstract article info Article history: Received 18 June 2008 Accepted 24 September 2008 Available online 17 November 2008 Keywords: Nereis diversicolor Scrobicularia plana Biomarkers Marsh areas The polychaete worm Nereis diversicolor and the clam Scrobicularia plana were collected from several sites, affected by different types of contamination, in a littoral enclosure in the SW Spain (Caño Sancti-Petri and Rio San Pedro). N. diversicolor was present in 6 sampling sites whereas S. plana in 4 of them. The aim of our study was to relate several pollution biomarkers to chemical sources (metals and organic pollutants e.g. PCB, PAH) in these species, thereby confirming their adequacy as sentinels for this habitat. The biomarkers surveyed in the two invertebrates were the activities of the antioxidant enzyme catalase (CAT), the phase II detoxifying enzyme glutathione S-transferase (GST) and the neurotoxicity marker acetylcholinesterase (AChE). Metallothionein (MT) levels were measured as a biomarker of exposure to metals. The results suggested a different response in the two sediment-dwelling organisms, the sediment-eating polychaete and the water- filtering clam, probably as a consequence of different contamination exposures. The results also sug- gested that samples from the “Caño Sancti-Petri” were exposed to biologically active compounds that altered some of their biochemical responses. Of all the biomarkers tested, AChE was the most sensitive one and N. diversicolor the potentially most robust sentinel in this ecosystem. In this low to moderately polluted environment, the biochemical approach better reflected temporal trends than site-related differences although it was also able to detect punctual chemical insults. © 2008 Elsevier Ltd. All rights reserved. 1. Introduction Littoral ecosystems are constantly threatened by pollution due to their proximity to human settlements with their associated agricul- tural and industrial activities. Our study site, “Caño Sancti-Petri”, is a salt marsh situated in the SW of Spain. It is a highly productive area where aquaculture and fishing activities have traditionally taken place. It is also important from an ecological point of view, which justified its qualification as a Natural Park in 1996. Despite this qualification, untreated domestic waste waters from a city with a population of 88,000 discharged directly into its core and, not until February 2002, did most of this load discharge cease thanks to the construction of a Sewage Treatment Plant (STP). The choice of a suite of biomarkers, rather than the chemical analysis alone, has been proposed as a more appropriate approach to monitor effects of pollutants in aquatic ecosystems (Cajaraville et al., 2000). Several field studies have proved to be successful using a multibiomarker approach in invertebrates (Porte et al., 2001; Kopecka et al., 2006; Durou et al., 2007; Lima et al., 2007; Martín-Díaz et al., 2008) and nowadays this is a recommended tool for pollution monitoring studies within many governmental institutions such as MAFF, IFREMER, UNEP, OECD, EU projects (e.g. BEEP), and it has been adopted by international conventions OSPAR, ICES. The suite of parameters selected were biomarkers of exposure aiming to detect specific-site contamination, or temporal trends, in the general stress condition of the two sentinels selected for the study. The biomarkers chosen were: the protein yield (PY), metallothionein (MT) levels, catalase (CAT), glutathione S-transferase (GST) and the acetylcholinesterase (AChE) activities. PY is a general marker of hepatic/digestive gland protein synthesis and, despite its unspecifi- city, it is usually enhanced under xenobiotic exposure. MT is a cystein- rich protein that binds to essential and non-essential metals facilitating either their transport (essentials) or inactivation (non- essential). Demonstration of increased synthesis under metal expo- sure has been given under field and laboratory studies (Viarengo et al., 2000). CAT is an antioxidant enzyme that eliminates H 2 O 2 thus preventing cell damage by reactive oxygen species (ROS), although its inducibility under field conditions is more controversial (Livingstone, 2001). GST is a phase II enzyme involved in the metabolism of Environment International 35 (2009) 523–531 ⁎ Corresponding author. Instituto de Ciencias Marinas de Andalucía (CSIC), Av. República Saharaui, 11510 Puerto Real, Cádiz, Spain. Tel.: + 34 93 230 95 00; fax: +34 93 230 95 55. E-mail address: msole@icm.csic.es (M. Solé). 0160-4120/$ – see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.envint.2008.09.013 Contents lists available at ScienceDirect Environment International journal homepage: www.elsevier.com/locate/envint