S128 Abstracts / Toxicology Letters 196S (2010) S37–S351 range of pyrene and survival, biochemical responses (metabolism, neurotransmission, biotransformation and oxidative stress) as well as behaviour endpoints (swimming resistance and distance cov- ered when swimming against the water flow) were assessed. The results showed that several biochemical parameters were altered after fish exposure to sub-lethal concentrations of pyrene. Possible associations between biochemical parameters and alterations on fish behaviour were also established. Globally, the results suggest that pyrene may affect the trophic webs highlighting the need of more studies on the subject. Acknowledgements: This study was conducted in the scope of the project RAMOCS – Implementation of Risk Assessment Methodologies for Oil and Chemical Spills in the European Marine Environment (ERA-AMPERA/0001/2007). doi:10.1016/j.toxlet.2010.03.446 P108-046 Effects of Pb exposure on oxidative stress biomarkers and plasma biochemistry in waterbirds from medina lagoon (Southern Spain) M. Martínez Haro 1 , A.J. Green 2 , J. Rodríguez-Estival 3 , P. Camarero 3 , R. Mateo 3 1 Instituto de Investigación en Recursos Cinegéticos/Estación Biológica de Do˜ nana, Spain, 2 Estación Biológica de Do˜ nana, Spain, 3 Instituto de Investigación en Recursos Cinegéticos, Spain Lead (Pb) shot pellet spent in hunting activities may be ingested by birds, that confused it with grit or seeds. In North America and Europe has been reported estimated mortalities for Pb shot ingestion for wintering waterfowl populations of 3% and 9%, respec- tively. Medina lagoon (Southern Spain) has the highest density of Pb shot in sediment of Europe (399 shot/m 2 , in the top 30 cm). In order to study Pb shot exposure for waterbirds in Medina lagoon, non-destructive monitoring was carried out by bit trapping during the wintering season 2006–2007, and post-breeding season 2007, 2008. Lead concentration in blood (PbB), ratio of ä-aminolevulinic acid dehydratase (ALAD) activity as specific biomarker for Pb expo- sure, parameters of oxidative stress in red blood cell (RBC) and plasma biochemistry were analyzed in blood samples. PbB in the four common pochard and 19% (n = 59) of mallard captured was higher to background level (200 ng/ml). Further, 50% and 5% of these pochard and mallard, respectively, showed PbB into severe clinical poisoning level (1000 ng/ml). In contrast, PbB of captured coot (n = 37) and moorhen (n = 12) were into background level. ALAD ratios decreased significantly with PbB in mallard and coot. In mallard, an inhibition of glutathione peroxidase (GPx) activity in RBC and an increase of oxidized glutathione (GSSH) were associ- ated with PbB into severe clinical poisoning level. In coot, PbB was negatively related to the levels of uric acid, retinol and carotenoids in plasma and glutathione (GSH) in RBC; but it was positively asso- ciated with increases of superoxide dismutase and GPx activities and GSSG/GSH ratio in RBC. Waterbirds exposed to Pb in an envi- ronment with a high Pb shot density have shown several adverse biochemical effects reflected by the inhibition of heme biosynthesis pathway and an increase in oxidative stress in blood. doi:10.1016/j.toxlet.2010.03.447 P108-047 Glutathione S-transferase activity, glutathione and lipid peroxidation levels in mallard (Anas platyrhynchos) erythrocytes exposed to lead and cadmium in vitro A. Hernández García 1 , D. Romero 1 , C.A. Tagliati 2 , C. Gravato 3 , L. Guilhermino 3 , A.J. García Fernández 1 1 University of Murcia, Area of Toxicology, Spain, 2 Universidade Federal de Minas Gerais, Belo Horizonte, Brazil, 3 CIMAR-LA/CIIMAR & ICBAS, Universidade do Porto, Portugal In birds, lead induces oxidative stress in several tissues such as liver, kidney and brain. However, little is known about its effect on birds’ erythrocytes. Similar information for cadmium is also scarce. In the present study, mallard (Anas platyrhynchos) erythrocytes were in vitro exposed to lead, to cadmium and to a cadmium–lead mixture in a proportion to those previously detected in blood of wild birds (1:10). Different concentrations were selected in order to evaluate glutathione (GSH) levels, glutathione S-transferase (GST) activity, and lipid peroxidation (LPO) through malondialdehyde (MDA) levels in haemolysates. In lead-exposure, GST activity was similar to control, except at EC 50 where the activity decreased. In both cadmium exposure and cadmium:lead mixture exposure, a decrease was detected for all the concentrations. GSH content of erythrocytes exposed to lead did not show statistically significant differences in relation to the control. However, cadmium and the mixture produced a statistically significant decrease of GSH con- tent. The increase of LPO was evident in all treatments, except for the highest cadmium concentration where the lipoperoxide lev- els were similar to control. In conclusion, the changes observed in these parameters in avian erythrocytes suggest that they may have potential for use as environmental biomarkers. Acknowledgements: This work has been supported by the Spanish Government (CGL2004-5959/BOS, CGL-2008- 4318/BOS, NOVEDAR-CSD00C-07-22204) and Seneca Foundation (08758/PI/08). Special thanks to P. María-Mojica for his help in sampling. doi:10.1016/j.toxlet.2010.03.448 P108-048 Effects on enzymatic antioxidant system of mallard (Anas platyrhynchos) erythrocytes exposed in vitro to lead and cadmium A. Hernández-García 1 , D. Romero 1 , C. Gravato 2 , L. Guilhermino 2 , A.J. García-Fernández 1 1 University of Mucia, Area of Toxicology, Spain, 2 CIMAR-LA/CIIMAR & ICBAS, Universidade do Porto, Portugal It has been suggested that heavy metal ions such as cadmium and lead have a prooxidant catalytic activity and can initiate membrane peroxidation by generating Reactive Oxygen Species and thereby interfering with the antioxidant system in tissues and erythrocytes, this fact is commonly known as oxidative stress. Erythrocytes have an efficient antioxidant mechanism to scavenge ROS and main- tain their integrity. This detoxifying system includes enzymatic and nonenzymatic antioxidant systems, and within enzymatic sys- tems, catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) are included. In birds, literature about oxidative stress in erythrocytes induced by lead and cadmium is scarce. In the present study, mallard (Anas platyrhynchos) erythrocytes were exposed to lead, cadmium and cadmium–lead combination