Bioaccumulation of Mercury in Marine Algae from Dakar Coast (Senegal) and Galician Rias (Spain)

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).