We studied the temporal variation of polycyclic aromatic hydrocarbons (PAH) levels in the wild mussel Mytilus galloprovincialis, water and sediment from 3 sampling sites on the Galician coast of Spain between the rias of Arousa and Muros, which were dramatically affected by the large oil spill from the oil tanker 'Prestige'. The samples were collected periodically, from November 22, 2002, 3 d after the tanker sank, until December 23, 2003. The total hydrocarbon content in the water and sediment samples was determined by fluorescence and expressed as concentration of chrysene. In addition, individual PAHs -analytes recommended by the US Environmental Protection Agency -were analysed in the mussel samples by HPLC using fluorimetric detection. A maximum concentration of 2.07 × 10 3 µg equiv. of chrysene l -1 was found in the water column at the sampling site of Furnas on November 29, 2002 which decreased to 0.21 µg l -1 by October 2003. Likewise, the concentrations of the sum of the 16 PAHs determined in the mussel samples collected at the sampling points were between 2.5 × 10 3 and 5.9 × 10 3 µg kg -1 dry weight in the days immediately following the oil spill and then decreased to 0.13 × 10 3 µg kg -1 in October 2003. However, no relevant information could be obtained from the PAH content of the sediment samples. A relation between parent PAHs accumulated in the mussels and their molecular weight (MW) has been found to provide an indication of hydrocarbon pollution. A good approximation was obtained when the total PAH content (ΣPAH) was represented versus the ratio of low MW PAHs to high MW PAHs (ΣLPAH:ΣHPAH). When the depuration rate r of individual PAHs by the mussels was fitted to an exponential model, 2 different values of r were found depending on the PAH concentration. The change from a slow to fast depuration rate was produced when the logarithm of the concentration was 1.0. KEY WORDS: 'Prestige' oil spill · PAH analysis · Mytilus · Mussels · Temporal variation Resale or republication not permitted without written consent of the publisher

Pollution of metal origin constitutes one of the major risks in the world today. The metal elements can be very dangerous to human health when they are present in the environment at high concentrations. Thus, the evaluation of the metal contamination in marine organisms, especially fish, makes it possible to predict a possible contamination of humans. This paper focuses on studying the metal contamination of the beach of Soumbédioune, located at the western frontage of the area of Dakar. This site, where fish products are offloaded, is the home to Canal IV (West Canal), which drains urban wastewater. In this study, we evaluated the concentrations of the metal elements (Fe, Zn 2+ , Cr 6+) in the bodies of Brama brama using a visible spectrophotometry UV. The results obtained show a strong concentration of chromium plates of 24,5 µg/g which is obtained at the level of the liver. Zinc presents a content of 16,7 µg/g at the level of the skin, but it was not detected at the level of the liver and the flesh. The maximum iron content was recorded at the level of the liver with a value of 77,5 µg/g. However, the values obtained were definitely higher than the standards established by FAO and the CEE.

Algae samples from Dakar coast (Senegal) and Galician Rias (Spain) were analyzed by cold vapor atomic absorption spectrometry (CV-AAS) to assess the bioaccumulation of mercury in the two aquatic systems. In this work, the contents of inorganic mercury and total mercury were determined. Simplified analytical procedures (microwave digestion and ultrasonic assisted extraction) were used for sample preparation. A reference material (BCR-60) was used to validate the analytical procedures used for sample preparation. The results of the analysis show that the total mercury contents found in algae samples from the Galician Rias are relatively similar to those found in algae samples from the Dakar coast. However, the inorganic mercury content of the algae from Pontevedra Ria was considerably higher than that found in the algae samples from Vigo Ria. The distribution was observed for inorganic mercury and total mercury, indicating that inorganic mercury is the major mercury species that bioaccumulates in marine algae. The inorganic mercury contents were always approximately equal to those of total mercury in the algae samples and a satisfactory correlation (p <0.0001; r = 0.9997) was obtained between them. Finally, the ANOVA analysis indicates that no significant difference (F = 0.165; p = 0.809) was found between the algae of the two aquatic systems (Dakar coast and Galician Rias).

Mussel samples from the Dakar coast (Senegal) were analysed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Microwave acid digestion was also employed for metals (Mn, Pb, Cd, As) determination. Dakar coast usually receives numerous domestic and industrial discharges without prior treatment. The contents of Arsenic were, in all cases, higher than other metals. However, the bivalve molluscs present themselves as effective bio-monitors when assessing marine aquatic pollution by contaminants in the Dakar coast. The ANOVA analysis allows concluding that significant differences were found between mussels from different sampling points. In all cases, the February samples have in all cases a higher content than those collected in October.