Evidence for contrasting accumulation pattern of cadmium in relation to other elements in Senilia senilis and Tagelus adansoni from the Bijags archipelago, Guinea-Bissau


Shellfish harvesting in intertidal areas is a widespread and economically important activity in many countries across West Africa. However, in some areas, there is virtually no information concerning the levels of contaminants (and other elements related to nutritional aspects) in the harvested species. We collected sediments and several individuals of the West African bloody cockle Senilia senilis and of the razor clam Tagelus adansoni during the dry season of 2015 nearby three islands in the Bijags archipelago, Guinea-Bissau. Aluminium, Ca, Fe, Mg, As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn were determined in sediments and whole soft tissues of the two bivalves. Sediments showed uniformly low trace element concentrations, pointing to an ecosystem with low levels of trace element contamination. T. adansoni presented higher concentrations of most elements than S. senilis, with the exception of Cd that showed up to 40 times higher values in S. senilis than in T. adansoni from the same sites. Furthermore, Cd concentrations (25 +/- 8.7 mg kg(-1), dw) in S. senilis are clearly above the maximum level established for human consumption. Future studies should clarify whether biological factors are the major responsible for this unusual situation.




Environmental Sciences & Ecology


Catry, T; Figueira, P; Carvalho, L; Monteiro, R; Coelho, P; Lourenco, PM; Catry, P; Tchantchalam, Q; Catry, I; Botelho, MJ; Pereira, E; Granadeiro, JP; Vale, C

nossos autores


This research was partially supported by the Strategic Funding UID/AMB/50017 (CESAM), UID/CTM/50011/2013 (CICECO), UID/Multi/04423/2013 (CIIMAR) and UID/MAR/04292/2013 (MARE) through national funds provided by FCT-Foundation for Science and Technology and European Regional Development Fund (ERDF), in the framework of the program PT2020. Further funds were provided by the MAVA Foundation through a project granted to IBAP (Guinea-Bissau) - 11-070 Evaluation et conservation de la biodiversite dans le Parc National Marin de Joao Vieira e Poilao. We thank IBAP sailors for important help during fieldwork. Thanks are also due to Alfredo da Silva, Aissa Regalla, Castro Barbosa and Justino Biai for granting permissions for work in the protected areas and for all facilities and logistical support. Rui Monteiro (SFRH/BD/108535/2015), Pedro Coelho (BPD/102870/2014), Pedro M. Lourenco (SFRH/BPD/84237/2012) and Ines Catry (SFRH/BPD/102637/2014) were supported by national funds through doctoral and post-doctoral grants from FCT.

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