Heavy metal concentrations in Squilla mantis (L.) (Crustacea, Stomatopoda) from the Gulf of Ca ´diz Evaluation of the impact of the Aznalcollar mining spill J. Blasco*, A.M. Arias, V. Sa ´enz Departamento Oceanografia, Instituto de Ciencias Marinas de Andalucı ´a (CSIC), Campus Universitario Rı ´o San Pedro, 11510 Puerto Real, Ca ´diz, Spain Received 30 June 2001; accepted 7 February 2002 Abstract After the Aznalco ´ llar mining spill (25th April 1998), considerable social concern arose amongst the inhabitants of the SW Iberian Peninsula concerning the consumption of local seafood. Squilla mantis was collected in four regions of the Gulf of Ca ´diz with a dual objective: to analyze the heavy metal levels for human consumption and as part of biomonitoring program. Heavy metal concentrations (Fe, Mn, Zn, Cu, Cd and Pb) were analyzed in soft tissues and cuticle. The highest values were found in the soft tissues for zinc, copper and cadmium and in the cuticle for iron, manganese and lead. The mean copper concentration in the soft tissue, corresponding to the edible part, was 27.1 mgÁg À1 wet weight. Approximately 80% of stations showed values higher than 20 mgÁg À1 wet weight of copper, the Spanish legal limit for the concentration of this metal in the crustacean for human consumption. For Zn and Cu no significant differences were found between regions, probably related with the capacity for regulation of S. mantis. The highest values found for copper in the Gulf of Ca ´diz compared to other areas is likely to be related with contamination from terrestrial mining activities (copper and pyrites) in the region, dating back to the times of Tartessians and Romans, rather than the effects of mining spill which was shown not to create any significant increases in heavy metal concentrations of organisms of the Guadalquivir River or the adjacent coastal area. D 2002 Elsevier Science Ltd. All rights reserved. Keywords: Heavy metals; Mining spill; Crustacean; Squilla mantis; The Gulf of Ca ´diz 1. Introduction The use of aquatic organisms to establish geographical and temporal variations in the bioavailabilities of heavy metals in coastal and estuarine waters is well established (Phillips, 1980; Phillips and Rainbow, 1993). Some crusta- ceans (particularly decapods) are large and easily identified and, from this point of view, could be considered as suitable candidates to be used as biomonitors. Nevertheless, their use has been criticised because they regulate the tissue concen- trations of trace elements such as copper, manganese and zinc to approximately constant concentrations over a wide range of metal availabilities (Rainbow and Phillips, 1993). Besides their potential employment as biomonitors, sev- eral species of crustaceans are included in the diet of coastal inhabitants and the concentrations of heavy metals consid- ered safe for human consumption in such seafood are regulated by legislation (BOE, 1991). After the Aznalco ´llar mining spill in southern Spain, considerable social concern arose amongst the inhabitants of the SW Iberian Peninsula concerning the consumption of local seafood. For this reason, an intensive biomonitoring program was carried out at several sampling stations in the estuary of the river Guadalquivir (Blasco et al., 1999; Sun ˜er et al., 1999) and in the Gulf of Ca ´diz. One species collected in the Gulf of Ca ´diz was a benthic crustacean, the mantis shrimp Squilla mantis (Stomatopoda). This species is com- mon in the diet of local inhabitants and its fishery has considerable economic importance. The Gulf of Ca ´diz receives effluent from the Guadiana and the Guadalquivir Rivers, with the Tinto and Odiel Rivers also representing significant sources of heavy metals. Important mines and relatively big cities and industries are situated in the drainage basin of these fluvial systems, and are responsible for metal loadings in the continental shelf waters of the Gulf of Ca ´diz (Elbaz-Poulichet and Leblanc, 1996). 0160-4120/02/$ – see front matter D 2002 Elsevier Science Ltd. All rights reserved. PII:S0160-4120(02)00014-4 * Corresponding author. Tel.: +34-9568-32612; fax: +34-9568-34701. E-mail address: julian.blasco@icman.csic.es (J. Blasco). www.elsevier.com/locate/envint Environment International 28 (2002) 111 –116