the marine environment may be of ecotoxicological concern due to modulation of fish biotransformation enzymes and crucial steroido- genic proteins. doi:10.1016/j.cbpa.2008.05.093 POSTER PRESENTATIONS 21. Extraction, separation and detection of Benzo(a)pyrene and the impact on the photosynthetic parameters of Gracilaria birdiae J.V. Almeida, D. Oliveira-Silva, R.L. Romano, E.M. Plastino, P. Colepicolo (University of São Paulo, Brazil); E. Marinho-Soriano (Federal University of Rio Grande do Norte, Brazil) Benzo(a)pyrene (BaP) is a five-ring polycyclic aromatic hydro- carbon and one of the priority pollutants listed by the protection agencies. There is a lack of knowledge about the BaP impacts on the marine environment. Marine algae play a central role as bioindicator of water pollution. It is well established that the presence of BaP induces oxidative stress in different organisms. In addition it is well known that reactive oxygen species (ROS) are involved in BaP biotransformation by monoxygenases, like cytochrome P450. An HPLC method was developed in order to detect BaP in marine algae cultures. BaP was analyzed in a HPLC system using a C18 column. The flow-rate was 1 mL/min with a gradient elution of acetonitrile/water (80/20 to 95/05). The calibration curve was linear within the range 0.25–50 ng/mL (r N 0.98). Due to the low levels of BaP and to achieve the fluorescent detection limit, concentration procedures were carried out on solid phase extractions (SPE). The effects of BaP on the electron transport rate in the photosynthetic process and the activity of other biomarkers of oxidative stress have been evaluated. This work was supported by FAPESP and CNPq. doi:10.1016/j.cbpa.2008.05.094 22. An ecotoxicological protocol with European eel, Anguilla anguilla, to assess the quality of marine sediments M. Benedetti, S. Gorbi, A. Notti, D. Fattorini, R. Bocchetti, E. Burioli, F. Regoli (Istituto di Biologia e Genetica, Università Politecnica delle Marche, Ancona, Italy); F. Sarti (Capitaneria di Porto di Ancona, Ancona, Italy) An ecotoxicological protocol was applied, in both field and labora- tory conditions, using the European eel Anguilla anguilla as model species to assess the quality and toxicological risks of marine sediments. Juveniles specimens were caged in different sites of the Ancona harbour, or exposed under semi-static laboratory conditions to contaminated sediments. Bioavailability of trace metals and polycyclic aromatic hydrocarbons was evaluated by comparing concentrations of these chemicals in sediments with those accumulated in tissues of exposed organisms. Potentially harmful effects of sediments were investigated integrating chemical data with a wide battery of cellular biomarkers including levels of metallothioneins, activity of biotrans- formation enzymes, aromatic metabolites in bile, activity of acet- ylcholinesterase, efficiency of antioxidant defences, total oxyradical scavenging capacity (TOSC) toward peroxyl and hydroxyl radicals, and loss of DNA integrity (strand breaks and frequency of micronuclei). Obtained results revealed the capability of eels to accumulate contaminants in hepatic tissues, thus offering the possibility to characterize the bioavailability of chemicals associated to sediments. Biological reactivity of sediments was confirmed by the induction cytochrome P450 biotransformation pathway and variations of several antioxidant responses; DNA alterations were observed only in laboratory conditions where more contaminated sediments were used. The overall results confirmed that the measurement of bioaccu- mulation and biological responses in the European eel can represent a valuable tool to assess the quality and toxicological risks of sediments. A similar approach can be particularly important to evaluate the impact of dredging activities when remobilization of pollutants from sediments can greatly affect their mobility, bioavailability and effects on organisms. doi:10.1016/j.cbpa.2008.05.095 23. Impact of the seasonal changes of the mussel digestive gland mass on the cytosolic metal and metallothionein concentrations Z. Dragun, M. Erk, B. Raspor, D. Ivanković, J. Pavičić (Ruđer Bošković Institute, Croatia) Mediterranean mussels (Mytilus galloprovincialis) are abundant sentinel species commonly used for the assessment of the metal contamination of the coastal marine areas. Digestive gland, as a main metabolic and storage tissue, is often selected for metal and metallothionein (MT) determination. Although the induction of MT is regarded as a biochemical response to metal exposure, it is often reported that biotic and abiotic factors (e.g. food abundance, reproductive status, temperature, salinity) additionally influence MT levels. The aim of our study was to estimate exposure of mussels to metals by means of MT level, using the caged mussels deployed over 12 months in the “hot spot” area of the Kaštela Bay (Dalmatia, Croatia). The results were evaluated following the recommendations of the MED POL Programme. Observed spring increase of the digestive gland mass caused the “biological dilution” of metal and MT concentrations, as the consequence of the growth of the gonadal tissue through the digestive gland. Thus, low concentrations of metal and MTs were observed during the gonad development stage. In order to assess MT and metal levels as the indicators of the metal exposure, additional parameters should be considered, e.g. the phase of the reproductive cycle and the digestive gland mass. doi:10.1016/j.cbpa.2008.05.096 24. Combined effects of abiotic and biotic variables on the energy metabolism and metallothionein level of Mytilus galloprovincialis M. Erk, D. Ivanković, J. Pavičić (Ruđer Bošković Institute, Division for Marine and Environmental Research, Zagreb, Croatia) Estuaries represent particularly variable environments charac- terised by large temporal and spatial fluctuations in abiotic factors such as salinity, temperature and dissolved oxygen (natural stress). Mussels (Mytilus galloprovincialis) living in these areas are generally able to cope with these changes owing to their ability to adapt to a S25 Abstracts / Comparative Biochemistry and Physiology, Part A 151 (2008) S19–S30